libpng: Update to 1.6.19.

author: Jose Fonseca <jfonseca@vmware.com> 2015-11-23 22:18:54 +0000
committer: Jose Fonseca <jfonseca@vmware.com> 2015-11-23 22:19:57 +0000
commit: ce651a7711042301cbc9c6866be0eeb9e1ceab66 (patch)
tree: c92185c5b69d0fef7c81d9c5a719ee60bdc29466
parent: c4cf34616e7fcf726438ae69a4415338430ebd02 (diff)
25 files changed, 1795 insertions, 2168 deletions
diff --git a/thirdparty/libpng/ANNOUNCE b/thirdparty/libpng/ANNOUNCE
index c514daf4..9f1b6658 100644
--- a/thirdparty/libpng/ANNOUNCE
+++ b/thirdparty/libpng/ANNOUNCE
@@ -1,4 +1,4 @@
-Libpng 1.6.16 - December 22, 2014
+Libpng 1.6.19 - November 12, 2015
 
 This is a public release of libpng, intended for use in production codes.
 
@@ -7,30 +7,104 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script
 
-   libpng-1.6.16.tar.xz (LZMA-compressed, recommended)
-   libpng-1.6.16.tar.gz
+   libpng-1.6.19.tar.xz (LZMA-compressed, recommended)
+   libpng-1.6.19.tar.gz
 
 Source files with CRLF line endings (for Windows), without the
 "configure" script
 
-   lpng1616.7z  (LZMA-compressed, recommended)
-   lpng1616.zip
+   lpng1619.7z  (LZMA-compressed, recommended)
+   lpng1619.zip
 
 Other information:
 
-   libpng-1.6.16-README.txt
-   libpng-1.6.16-LICENSE.txt
-   libpng-1.6.16-*.asc (armored detached GPG signatures)
-
-Changes since the last public release (1.6.15):
-  Added ".align 2" to arm/filter_neon.S to support old GAS assemblers that
-    don't do alignment correctly.
-  Revised Makefile.am and scripts/*.dfn to work with MinGW/MSYS;
-    renamed scripts/*.dfn to scripts/*.c (Bob Friesenhahn and John Bowler).
-  Quiet a "comparison always true" warning in pngstest.c (John Bowler).
-  Restored a test on width that was removed from png.c at libpng-1.6.9
-    (Bug report by Alex Eubanks).
-  Fixed an overflow in png_combine_row with very wide interlaced images.
+   libpng-1.6.19-README.txt
+   libpng-1.6.19-LICENSE.txt
+   libpng-1.6.19-*.asc (armored detached GPG signatures)
+
+Changes since the last public release (1.6.18):
+
+  Updated obsolete information about the simplified API macros in the
+    manual pages (Bug report by Arc Riley).
+  Avoid potentially dereferencing NULL info_ptr in png_info_init_3().
+  Rearranged png.h to put the major sections in the same order as
+    in libpng17.
+  Eliminated unused PNG_COST_SHIFT, PNG_WEIGHT_SHIFT, PNG_COST_FACTOR, and
+    PNG_WEIGHT_FACTOR macros.
+  Suppressed some warnings from the Borland C++ 5.5.1/5.82 compiler
+    (Bug report by Viktor Szakats).  Several warnings remain and are
+    unavoidable, where we test for overflow.
+  Fixed potential leak of png_pixels in contrib/pngminus/pnm2png.c
+  Fixed uninitialized variable in contrib/gregbook/rpng2-x.c
+  Moved config.h.in~ from the "libpng_autotools_files" list to the
+    "libpng_autotools_extra" list in autogen.sh because it was causing a
+    false positive for missing files (bug report by Robert C. Seacord).
+  Removed unreachable "break" statements in png.c, pngread.c, and pngrtran.c
+    to suppress clang warnings (Bug report by Viktor Szakats).
+  Fixed some bad links in the man page.
+  Changed "n bit" to "n-bit" in comments.
+  Added signed/unsigned 16-bit safety net. This removes the dubious
+    0x8000 flag definitions on 16-bit systems. They aren't supported
+    yet the defs *probably* work, however it seems much safer to do this
+    and be advised if anyone, contrary to advice, is building libpng 1.6
+    on a 16-bit system. It also adds back various switch default clauses
+    for GCC; GCC errors out if they are not present (with an appropriately
+    high level of warnings).
+  Safely convert num_bytes to a png_byte in png_set_sig_bytes() (Robert
+    Seacord).
+  Fixed the recently reported 1's complement security issue by replacing
+    the value that is illegal in the PNG spec, in both signed and unsigned
+    values, with 0. Illegal unsigned values (anything greater than or equal
+    to  0x80000000) can still pass through, but since these are not illegal
+    in ANSI-C (unlike 0x80000000 in the signed case) the checking that
+    occurs later can catch them (John Bowler).
+  Fixed png_save_int_32 when int is not 2's complement (John Bowler).
+  Updated libpng16 with all the recent test changes from libpng17,
+    including changes to pngvalid.c to ensure that the original,
+    distributed, version of contrib/visupng/cexcept.h can be used
+    (John Bowler).
+  pngvalid contains the correction to the use of SAVE/STORE_
+    UNKNOWN_CHUNKS; a bug revealed by changes in libpng 1.7. More
+    tests contain the --strict option to detect warnings and the
+    pngvalid-standard test has been corrected so that it does not
+    turn on progressive-read. There is a separate test which does
+    that. (John Bowler)
+  Also made some signed/unsigned fixes.
+  Make pngstest error limits version specific. Splitting the machine
+    generated error structs out to a file allows the values to be updated
+    without changing pngstest.c itself. Since libpng 1.6 and 1.7 have
+    slightly different error limits this simplifies maintenance. The
+    makepngs.sh script has also been updated to more accurately reflect
+    current problems in libpng 1.7 (John Bowler).
+  Incorporated new test PNG files into make check.  tests/pngstest-*
+    are changed so that the new test files are divided into 8 groups by
+    gamma and alpha channel.  These tests have considerably better code
+    and pixel-value coverage than contrib/pngsuite; however,coverage is
+    still incomplete (John Bowler).
+  Removed the '--strict' in 1.6 because of the double-gamma-correction
+    warning, updated pngstest-errors.h for the errors detected with the
+    new contrib/testspngs PNG test files (John Bowler).
+  Worked around rgb-to-gray issues in libpng 1.6.  The previous
+    attempts to ignore the errors in the code aren't quite enough to
+    deal with the 'channel selection' encoding added to libpng 1.7; abort.
+  Fixed 'pow' macros in pngvalid.c. It is legal for 'pow' to be a
+    macro, therefore the argument list cannot contain preprocessing
+    directives.  Make sure pow is a function where this happens. This is
+    a minimal safe fix, the issue only arises in non-performance-critical
+    code (bug report by Curtis Leach, fix by John Bowler).
+  Added sPLT support to pngtest.c
+  Prevent setting or writing over-length PLTE chunk (Cosmin Truta).
+  Silently truncate over-length PLTE chunk while reading.
+  Libpng incorrectly calculated the output rowbytes when the application
+    decreased either the number of channels or the bit depth (or both) in
+    a user transform.  This was safe; libpng overallocated buffer space
+   (potentially by quite a lot; up to 4 times the amount required) but,
+   from 1.5.4 on, resulted in a png_error (John Bowler).
+  Fixed some inconsequential cut-and-paste typos in png_set_cHRM_XYZ_fixed().
+  Clarified COPYRIGHT information to state explicitly that versions
+    are derived from previous versions.
+  Removed much of the long list of previous versions from png.h and
+    libpng.3.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/thirdparty/libpng/CHANGES b/thirdparty/libpng/CHANGES
index 68a80a58..2e4d2bb2 100644
--- a/thirdparty/libpng/CHANGES
+++ b/thirdparty/libpng/CHANGES
@@ -1,11 +1,14 @@
-
+#if 0
 CHANGES - changes for libpng
 
-Version 0.2
+version 0.1 [March 29, 1995]
+  initial work-in-progress release
+
+version 0.2 [April 1, 1995]
   added reader into png.h
   fixed small problems in stub file
 
-Version 0.3
+version 0.3 [April 8, 1995]
   added pull reader
   split up pngwrite.c to several files
   added pnglib.txt
@@ -14,9 +17,9 @@ Version 0.3
   fixed some bugs in writer
   interfaced with zlib 0.5
   added K&R support
-  added check for 64 KB blocks for 16-bit machines
+  added check for 64 KB blocks for 16 bit machines
 
-Version 0.4
+version 0.4 [April 26, 1995]
   cleaned up code and commented code
   simplified time handling into png_time
   created png_color_16 and png_color_8 to handle color needs
@@ -27,28 +30,29 @@ Version 0.4
   cleaned up zTXt reader and writer (using zlib's Reset functions)
   split transformations into pngrtran.c and pngwtran.c
 
-Version 0.5
+version 0.5 [April 30, 1995]
   interfaced with zlib 0.8
   fixed many reading and writing bugs
   saved using 3 spaces instead of tabs
 
-Version 0.6
+version 0.6 [May 1, 1995]
+  first beta release
   added png_large_malloc() and png_large_free()
   added png_size_t
   cleaned up some compiler warnings
   added png_start_read_image()
 
-Version 0.7
+version 0.7 [June 24, 1995]
   cleaned up lots of bugs
   finished dithering and other stuff
   added test program
   changed name from pnglib to libpng
 
-Version 0.71 [June, 1995]
+version 0.71 [June 26, 1995]
   changed pngtest.png for zlib 0.93
   fixed error in libpng.txt and example.c
 
-Version 0.8
+version 0.8 [August 20, 1995]
   cleaned up some bugs
   added png_set_filler()
   split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
@@ -91,7 +95,7 @@ Version 0.88 [January, 1996]
   cleaned up documentation
   added callbacks for read/write and warning/error functions
 
-Version 0.89 [July, 1996]
+Version 0.89 [June 5, 1996]
   Added new initialization API to make libpng work better with shared libs
     we now have png_create_read_struct(), png_create_write_struct(),
     png_create_info_struct(), png_destroy_read_struct(), and
@@ -118,6 +122,9 @@ Version 0.89 [July, 1996]
   New pngtest image also has interlacing and zTXt
   Updated documentation to reflect new API
 
+Version 0.89c [June 17, 1996]
+  Bug fixes.
+
 Version 0.90 [January, 1997]
   Made CRC errors/warnings on critical and ancillary chunks configurable
   libpng will use the zlib CRC routines by (compile-time) default
@@ -158,7 +165,7 @@ Version 0.95 [March, 1997]
   Added new pCAL chunk read/write support
   Added experimental filter selection weighting (Greg Roelofs)
   Removed old png_set_rgbx() and png_set_xrgb() functions that have been
-     obsolete for about 2 years now (use png_set_filler() instead)
+    obsolete for about 2 years now (use png_set_filler() instead)
   Added macros to read 16- and 32-bit ints directly from buffer, to be
     used only on those systems that support it (namely PowerPC and 680x0)
     With some testing, this may become the default for MACOS/PPC systems.
@@ -440,7 +447,7 @@ Version 1.0.3 [January 14, 1999]
 
 Version 1.0.3a [August 12, 1999]
   Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
-     if an attempt is made to read an interlaced image when it's not supported.
+    if an attempt is made to read an interlaced image when it's not supported.
   Added check if png_ptr->trans is defined before freeing it in pngread.c
   Modified the Y2K statement to include versions back to version 0.71
   Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
@@ -448,7 +455,7 @@ Version 1.0.3a [August 12, 1999]
   Replaced leading blanks with tab characters in makefile.hux
   Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
   Changed (float)red and (float)green to (double)red, (double)green
-     in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
+    in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
   Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
   Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
   Updated documentation to refer to the PNG-1.2 specification.
@@ -491,7 +498,7 @@ Version 1.0.3d [September 4, 1999]
   Added new png_expand functions to scripts/pngdef.pas and pngos2.def
   Added a demo read_user_transform_fn that examines the row filters in pngtest.c
 
-Version 1.0.4 [September 24, 1999]
+Version 1.0.4 [September 24, 1999, not distributed publicly]
   Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
   Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
   Made several minor corrections to pngtest.c
@@ -518,6 +525,7 @@ Version 1.0.4c [October 1, 1999]
   Added a "png_check_version" function in png.c and pngtest.c that will generate
     a helpful compiler error if an old png.h is found in the search path.
   Changed type of png_user_transform_depth|channels from int to png_byte.
+  Added "Libpng is OSI Certified Open Source Software" statement to png.h
 
 Version 1.0.4d [October 6, 1999]
   Changed 0.45 to 0.45455 in png_set_sRGB()
@@ -904,7 +912,7 @@ Version 1.0.7 [July 1, 2000]
 Version 1.0.8beta1 [July 8, 2000]
   Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks.
   Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and
-     pngwutil.c.
+    pngwutil.c.
   Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h.
   Removed unused "#include <assert.h>" from png.c
   Added WindowsCE support.
@@ -912,12 +920,12 @@ Version 1.0.8beta1 [July 8, 2000]
 
 Version 1.0.8beta2 [July 10, 2000]
   Added project files to the wince directory and made further revisions
-     of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
+    of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
 
 Version 1.0.8beta3 [July 11, 2000]
   Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS()
-     for indexed-color input files to avoid potential double-freeing trans array
-     under some unusual conditions; problem was introduced in version 1.0.6f.
+    for indexed-color input files to avoid potential double-freeing trans array
+    under some unusual conditions; problem was introduced in version 1.0.6f.
   Further revisions to pngtest.c and files in the wince subdirectory.
 
 Version 1.0.8beta4 [July 14, 2000]
@@ -1089,16 +1097,16 @@ Version 1.2.0beta3 [May 17, 2001]
 
 Version 1.2.0beta4 [June 23, 2001]
   Check for missing profile length field in iCCP chunk and free chunk_data
-     in case of truncated iCCP chunk.
+    in case of truncated iCCP chunk.
   Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc
   Bumped dll-number from 2 to 3 in makefile.cygwin
   Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
-     if user attempts to run it on an 8-bit display.
+    if user attempts to run it on an 8-bit display.
   Updated contrib/gregbook
   Use png_malloc instead of png_zalloc to allocate palette in pngset.c
   Updated makefile.ibmc
   Added some typecasts to eliminate gcc 3.0 warnings.  Changed prototypes
-     of png_write_oFFS width and height from png_uint_32 to png_int_32.
+    of png_write_oFFS width and height from png_uint_32 to png_int_32.
   Updated example.c
   Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c
 
@@ -1106,9 +1114,9 @@ Version 1.2.0beta5 [August 8, 2001]
   Revised contrib/gregbook
   Revised makefile.gcmmx
   Revised pnggccrd.c to conditionally compile some thread-unsafe code only
-     when PNG_THREAD_UNSAFE_OK is defined.
+    when PNG_THREAD_UNSAFE_OK is defined.
   Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with
-     value exceeding 2^bit_depth-1
+    value exceeding 2^bit_depth-1
   Revised makefile.sgi and makefile.sggcc
   Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c
   Removed restriction that do_invert_mono only operate on 1-bit opaque files
@@ -1449,8 +1457,9 @@ Version 1.2.6beta4 [July 28, 2004]
   Use png_malloc instead of png_zalloc to allocate the pallete.
 
 Version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004]
-  Fixed buffer overflow vulnerability in png_handle_tRNS()
-  Fixed integer arithmetic overflow vulnerability in png_read_png().
+  Fixed buffer overflow vulnerability (CVE-2004-0597) in png_handle_tRNS().
+  Fixed NULL dereference vulnerability (CVE-2004-0598) in png_handle_iCCP().
+  Fixed integer overflow vulnerability (CVE-2004-0599) in png_read_png().
   Fixed some harmless bugs in png_handle_sBIT, etc, that would cause
     duplicate chunk types to go undetected.
   Fixed some timestamps in the -config version
@@ -1493,7 +1502,7 @@ Version 1.0.16rc4 and 1.2.6rc4 [August 10, 2004]
 
 Version 1.0.16rc5 and 1.2.6rc5 [August 10, 2004]
   Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_ASSEMBLER_CODE_SUPPORTED
-     section of png.h where they were inadvertently placed in version rc3.
+    section of png.h where they were inadvertently placed in version rc3.
 
 Version 1.2.6 and 1.0.16 [August 15, 2004]
   Revised pngtest so memory allocation testing is only done when PNG_DEBUG==1.
@@ -2102,7 +2111,7 @@ Version 1.4.0beta24 [July 25, 2008]
     png_decompress_chunk(), and remove "chunkdata" from parameter list.
   Put a call to png_check_chunk_name() in png_read_chunk_header().
   Revised png_check_chunk_name() to reject a name with a lowercase 3rd byte.
-  Removed two calls to png_check_chunk_name() occuring later in the process.
+  Removed two calls to png_check_chunk_name() occurring later in the process.
   Define PNG_NO_ERROR_NUMBERS by default in pngconf.h
 
 Version 1.4.0beta25 [July 30, 2008]
@@ -2325,7 +2334,7 @@ Version 1.4.0beta63 [June 15, 2009]
 Version 1.4.0beta64 [June 24, 2009]
   Eliminated PNG_LEGACY_SUPPORTED code.
   Moved the various unknown chunk macro definitions outside of the
-     PNG_READ|WRITE_ANCILLARY_CHUNK_SUPPORTED blocks.
+    PNG_READ|WRITE_ANCILLARY_CHUNK_SUPPORTED blocks.
 
 Version 1.4.0beta65 [June 26, 2009]
   Added a reference to the libpng license in each file.
@@ -3747,8 +3756,9 @@ Version 1.5.7beta04 [November 17, 2011]
 
 Version 1.5.7beta05 [November 25, 2011]
   Removed "zTXt" from warning in generic chunk decompression function.
-  Validate time settings passed to pngset() and png_convert_to_rfc1123()
-    (Frank Busse).
+  Validate time settings passed to png_set_tIME() and png_convert_to_rfc1123()
+    (Frank Busse). Note: This prevented CVE-2015-7981 from affecting
+    libpng-1.5.7 and later.
   Added MINGW support to CMakeLists.txt
   Reject invalid compression flag or method when reading the iTXt chunk.
   Backed out 'simplified' API changes. The API seems too complex and there
@@ -3794,12 +3804,13 @@ Version 1.6.0beta01 [December 15, 2011]
     (the other two required headers aren't used).  Non-ANSI systems that don't
     have stddef.h or limits.h will have to provide an appropriate fake
     containing the relevant types and #defines.
-  The use of FAR/far has been eliminated and the definition of png_alloc_size_t
-    is now controlled by a flag so that 'small size_t' systems can select it
-    if necessary.  Libpng 1.6 may not currently work on such systems -- it
-    seems likely that it will ask 'malloc' for more than 65535 bytes with any
-    image that has a sufficiently large row size (rather than simply failing
-    to read such images).
+  Dropped support for 16-bit platforms. The use of FAR/far has been eliminated
+    and the definition of png_alloc_size_t is now controlled by a flag so
+    that 'small size_t' systems can select it if necessary.  Libpng 1.6 may
+    not currently work on such systems -- it seems likely that it will
+    ask 'malloc' for more than 65535 bytes with any image that has a
+    sufficiently large row size (rather than simply failing to read such
+    images).
   New tools directory containing tools used to generate libpng code.
   Fixed race conditions in parallel make builds. With higher degrees of
     parallelism during 'make' the use of the same temporary file names such
@@ -4411,7 +4422,7 @@ Version 1.6.1beta02 [February 19, 2013]
 
 Version 1.6.1beta03 [February 22, 2013]
   Fixed ALIGNED_MEMORY support.
-  Allow run-time ARM NEON checking to be disabled. A new configure option:
+  Added a new configure option:
     --enable-arm-neon=always will stop the run-time checks. New checks
     within arm/arm_init.c will cause the code not to be compiled unless
     __ARM_NEON__ is set. This should make it fail safe (if someone asks
@@ -4430,10 +4441,10 @@ Version 1.6.1beta05 [March 1, 2013]
 Version 1.6.1beta06 [March 4, 2013]
   Better documentation of unknown handling API interactions.
   Corrected Android builds and corrected libpng.vers with symbol
-    prefixing. This adds an API to set optimization options externally,
+    prefixing.  It also makes those tests compile and link on Android.
+  Added an API png_set_option() to set optimization options externally,
     providing an alternative and general solution for the non-portable
-    run-time tests used by the ARM Neon code.  It also makes those tests
-    compile and link on Android.
+    run-time tests used by the ARM Neon code, using the PNG_ARM_NEON option.
   The order of settings vs options in pnglibconf.h is reversed to allow
     settings to depend on options and options can now set (or override) the
     defaults for settings.
@@ -4525,13 +4536,14 @@ Version 1.6.3beta03 [April 30, 2013]
   Expanded manual paragraph about writing private chunks, particularly
     the need to call png_set_keep_unknown_chunks() when writing them.
   Avoid dereferencing NULL pointer possibly returned from
-     png_create_write_struct() (Andrew Church).
+    png_create_write_struct() (Andrew Church).
 
 Version 1.6.3beta05 [May 9, 2013]
   Calculate our own zlib windowBits when decoding rather than trusting the
     CMF bytes in the PNG datastream.
   Added an option to force maximum window size for inflating, which was
-    the behavior of libpng15 and earlier.
+    the behavior of libpng15 and earlier, via a new PNG_MAXIMUM_INFLATE_WINDOW
+    option for png_set_options().
   Added png-fix-itxt and png-fix-too-far-back to the built programs and
     removed warnings from the source code and timepng that are revealed as
     a result.
@@ -5114,17 +5126,294 @@ Version 1.6.16beta03 [December 21, 2014]
 
 Version 1.6.16rc01 [December 21, 2014]
   Restored a test on width that was removed from png.c at libpng-1.6.9
-    (Bug report by Alex Eubanks).
+    (Bug report by Alex Eubanks, CVE-2015-0973).
 
 Version 1.6.16rc02 [December 21, 2014]
   Undid the update to pngrutil.c in 1.6.16rc01.
 
 Version 1.6.16rc03 [December 21, 2014]
-  Fixed an overflow in png_combine_row with very wide interlaced images.
+  Fixed an overflow in png_combine_row() with very wide interlaced images
+    (Bug report and fix by John Bowler, CVE-2014-9495).
 
 Version 1.6.16 [December 22, 2014]
   No changes.
 
+Version 1.6.17beta01 [January 29, 2015]
+  Removed duplicate PNG_SAFE_LIMITS_SUPPORTED handling from pngconf.h
+  Corrected the width limit calculation in png_check_IHDR().
+  Removed user limits from pngfix. Also pass NULL pointers to
+    png_read_row to skip the unnecessary row de-interlace stuff.
+  Added testing of png_set_packing() to pngvalid.c
+  Regenerated configure scripts in the *.tar distributions with libtool-2.4.4
+  Implement previously untested cases of libpng transforms in pngvalid.c
+  Fixed byte order in png_do_read_filler() with 16-bit input. Previously
+    the high and low bytes of the filler, from png_set_filler() or from
+    png_set_add_alpha(), were read in the wrong order.
+  Made the check for out-of-range values in png_set_tRNS() detect
+    values that are exactly 2^bit_depth, and work on 16-bit platforms.
+  Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
+  Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
+    pngset.c to avoid warnings about dead code.
+  Added "& 0xff" to many instances of expressions that are typecast
+    to (png_byte), to avoid Coverity warnings.
+
+Version 1.6.17beta02 [February 7, 2015]
+  Work around one more Coverity-scan dead-code warning.
+  Do not build png_product2() when it is unused.
+
+Version 1.6.17beta03 [February 17, 2015]
+  Display user limits in the output from pngtest.
+  Eliminated the PNG_SAFE_LIMITS macro and restored the 1-million-column
+    and 1-million-row default limits in pnglibconf.dfa, that can be reset
+    by the user at build time or run time.  This provides a more robust
+    defense against DOS and as-yet undiscovered overflows.
+
+Version 1.6.17beta04 [February 21, 2015]
+  Added PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED macro, on by default.
+  Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
+  Rebuilt configure scripts with automake-1.15 and libtool-2.4.6
+
+Version 1.6.17beta05 [February 25, 2015]
+  Restored compiling of png_reciprocal2 with PNG_NO_16BIT.
+
+Version 1.6.17beta06 [February 27, 2015]
+  Moved png_set_filter() prototype into a PNG_WRITE_SUPPORTED block
+    of png.h.
+  Avoid runtime checks when converting integer to png_byte with
+    Visual Studio (Sergey Kosarevsky)
+
+Version 1.6.17rc01 [March 4, 2015]
+  No changes.
+
+Version 1.6.17rc02 [March 9, 2015]
+  Removed some comments that the configure script did not handle
+    properly from scripts/pnglibconf.dfa and pnglibconf.h.prebuilt.
+  Free the unknown_chunks structure even when it contains no data.
+
+Version 1.6.17rc03 [March 12, 2015]
+  Updated CMakeLists.txt to add OSX framework, change YES/NO to ON/OFF
+    for consistency, and remove some useless tests (Alexey Petruchik).
+
+Version 1.6.17rc04 [March 16, 2015]
+  Remove pnglibconf.h, pnglibconf.c, and pnglibconf.out instead of
+    pnglibconf.* in "make clean" (Cosmin).
+  Fix bug in calculation of maxbits, in png_write_sBIT, introduced
+    in libpng-1.6.17beta01 (John Bowler).
+
+Version 1.6.17rc05 [March 21, 2015]
+  Define PNG_FILTER_* and PNG_FILTER_VALUE_* in png.h even when WRITE
+    is not supported (John Bowler).  This fixes an error introduced in
+    libpng-1.6.17beta06.
+  Reverted "& 0xff" additions of version 1.6.17beta01. Libpng passes
+    the Coverity scan without them.
+
+Version 1.6.17rc06 [March 23, 2015]
+  Remove pnglibconf.dfn and pnglibconf.pre with "make clean".
+  Reformatted some "&0xff" instances to "& 0xff".
+  Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
+    value was wrong.  It's not clear if this affected the final stored
+    value; in the obvious code path the upper and lower 8-bits of the
+    alpha value were identical and the alpha was truncated to 8-bits
+    rather than dividing by 257 (John Bowler).
+
+Version 1.6.17 [March 26, 2015]
+  No changes.
+
+Version 1.6.18beta01 [April 1, 2015]
+  Removed PNG_SET_CHUNK_[CACHE|MALLOC]_LIMIT_SUPPORTED macros.  They
+    have been combined with PNG_SET_USER_LIMITS_SUPPORTED (resolves
+    bug report by Andrew Church).
+  Fixed rgb_to_gray checks and added tRNS checks to pngvalid.c.  This
+    fixes some arithmetic errors that caused some tests to fail on
+    some 32-bit platforms (Bug reports by Peter Breitenlohner [i686]
+    and Petr Gajdos [i586]).
+
+Version 1.6.18beta02 [April 26, 2015]
+  Suppressed some warnings from the Borland C++ 5.5.1/5.82 compiler
+    (Bug report by Viktor Szakats).
+
+Version 1.6.18beta03 [May 6, 2015]
+  Replaced "unexpected" with an integer (0xabadca11) in pngset.c
+    where a long was expected, to avoid a compiler warning when PNG_DEBUG > 1.
+  Added contrib/examples/simpleover.c, to demonstrate how to handle
+    alpha compositing of multiple images, using the "simplified API"
+    and an example PNG generation tool, contrib/examples/genpng.c
+    (John Bowler).
+
+Version 1.6.18beta04 [May 20, 2015]
+  PNG_RELEASE_BUILD replaces tests where the code depended on the build base
+    type and can be defined on the command line, allowing testing in beta
+    builds (John Bowler).
+  Avoid Coverity issue 80858 (REVERSE NULL) in pngtest.c PNG_DEBUG builds.
+  Avoid a harmless potential integer overflow in png_XYZ_from_xy() (Bug
+    report from Christopher Ferris).
+
+Version 1.6.18beta05 [May 31, 2015]
+  Backport filter selection code from libpng-1.7.0beta51, to combine
+    sub_row, up_row, avg_row, and paeth_row into try_row and tst_row.
+  Changed png_voidcast(), etc., to voidcast(), etc., in contrib/tools/pngfix.c
+    to avoid confusion with the libpng private macros.
+  Fixed old cut&paste bug in the weighted filter selection code in
+    pngwutil.c, introduced in libpng-0.95, March 1997.
+
+Version 1.6.18beta06 [June 1, 2015]
+  Removed WRITE_WEIGHTED_FILTERED code, to save a few kbytes of the
+    compiled library size. It never worked properly and as far as we can
+    tell, no one uses it. The png_set_filter_heuristics() and
+    png_set_filter_heuristics_fixed() APIs are retained but deprecated
+    and do nothing.
+
+Version 1.6.18beta07 [June 6, 2015]
+  Removed non-working progressive reader 'skip' function. This
+    function has apparently never been used. It was implemented
+    to support back-door modification of png_struct in libpng-1.4.x
+    but (because it does nothing and cannot do anything) was apparently
+    never tested (John Bowler).
+  Fixed cexcept.h in which GCC 5 now reports that one of the auto
+    variables in the Try macro needs to be volatile to prevent value
+    being lost over the setjmp (John Bowler).
+  Fixed NO_WRITE_FILTER and -Wconversion build breaks (John Bowler).
+  Fix g++ build breaks (John Bowler).
+  Quieted some Coverity issues in pngfix.c, png-fix-itxt.c, pngvalid.c,
+    pngstest.c, and pngimage.c. Most seem harmless, but png-fix-itxt
+    would only work with iTXt chunks with length 255 or less.
+  Added #ifdef's to contrib/examples programs so people don't try
+    to compile them without the minimum required support enabled
+    (suggested by Flavio Medeiros).
+
+Version 1.6.18beta08 [June 30, 2015]
+  Eliminated the final two Coverity defects (insecure temporary file
+    handling in contrib/libtests/pngstest.c; possible overflow of
+    unsigned char in contrib/tools/png-fix-itxt.c). To use the "secure"
+    file handling, define PNG_USE_MKSTEMP, otherwise "tmpfile()" will
+    be used.
+  Removed some unused WEIGHTED_FILTER macros from png.h and pngstruct.h
+
+Version 1.6.18beta09 [July 5, 2015]
+  Removed some useless typecasts from contrib/tools/png-fix-itxt.c
+  Fixed a new signed-unsigned comparison in pngrtran.c (Max Stepin).
+  Replaced arbitrary use of 'extern' with #define PNG_LINKAGE_*.  To
+    preserve API compatibility, the new defines all default to "extern"
+    (requested by Jan Nijtmans).
+
+Version 1.6.18rc01 [July 9, 2015]
+  Belatedly added Mans Rullgard and James Yu to the list of Contributing
+    Authors.
+
+Version 1.6.18rc02 [July 12, 2015]
+  Restored unused FILTER_HEURISTIC macros removed at libpng-1.6.18beta08
+    to png.h to avoid compatibility warnings.
+
+Version 1.6.18rc03 [July 15, 2015]
+  Minor changes to the man page
+
+Version 1.6.18 [July 23, 2015]
+  No changes.
+
+Version 1.6.19beta01 [July 30, 2015]
+  Updated obsolete information about the simplified API macros in the
+    manual pages (Bug report by Arc Riley).
+  Avoid potentially dereferencing NULL info_ptr in png_info_init_3().
+  Rearranged png.h to put the major sections in the same order as
+    in libpng17.
+  Eliminated unused PNG_COST_SHIFT, PNG_WEIGHT_SHIFT, PNG_COST_FACTOR, and
+    PNG_WEIGHT_FACTOR macros.
+  Suppressed some warnings from the Borland C++ 5.5.1/5.82 compiler
+    (Bug report by Viktor Szakats).  Several warnings remain and are
+    unavoidable, where we test for overflow.
+  Fixed potential leak of png_pixels in contrib/pngminus/pnm2png.c
+  Fixed uninitialized variable in contrib/gregbook/rpng2-x.c
+
+Version 1.6.19beta02 [August 19, 2015]
+  Moved config.h.in~ from the "libpng_autotools_files" list to the
+    "libpng_autotools_extra" list in autogen.sh because it was causing a
+    false positive for missing files (bug report by Robert C. Seacord).
+  Removed unreachable "break" statements in png.c, pngread.c, and pngrtran.c
+    to suppress clang warnings (Bug report by Viktor Szakats).
+  Fixed some bad links in the man page.
+  Changed "n bit" to "n-bit" in comments.
+  Added signed/unsigned 16-bit safety net. This removes the dubious
+    0x8000 flag definitions on 16-bit systems. They aren't supported
+    yet the defs *probably* work, however it seems much safer to do this
+    and be advised if anyone, contrary to advice, is building libpng 1.6
+    on a 16-bit system. It also adds back various switch default clauses
+    for GCC; GCC errors out if they are not present (with an appropriately
+    high level of warnings).
+  Safely convert num_bytes to a png_byte in png_set_sig_bytes() (Robert
+    Seacord).
+  Fixed the recently reported 1's complement security issue by replacing
+    the value that is illegal in the PNG spec, in both signed and unsigned
+    values, with 0. Illegal unsigned values (anything greater than or equal
+    to  0x80000000) can still pass through, but since these are not illegal
+    in ANSI-C (unlike 0x80000000 in the signed case) the checking that
+    occurs later can catch them (John Bowler).
+
+Version 1.6.19beta03 [September 26, 2015]
+  Fixed png_save_int_32 when int is not 2's complement (John Bowler).
+  Updated libpng16 with all the recent test changes from libpng17,
+    including changes to pngvalid.c to ensure that the original,
+    distributed, version of contrib/visupng/cexcept.h can be used
+    (John Bowler).
+  pngvalid contains the correction to the use of SAVE/STORE_
+    UNKNOWN_CHUNKS; a bug revealed by changes in libpng 1.7. More
+    tests contain the --strict option to detect warnings and the
+    pngvalid-standard test has been corrected so that it does not
+    turn on progressive-read. There is a separate test which does
+    that. (John Bowler)
+  Also made some signed/unsigned fixes.
+  Make pngstest error limits version specific. Splitting the machine
+    generated error structs out to a file allows the values to be updated
+    without changing pngstest.c itself. Since libpng 1.6 and 1.7 have
+    slightly different error limits this simplifies maintenance. The
+    makepngs.sh script has also been updated to more accurately reflect
+    current problems in libpng 1.7 (John Bowler).
+  Incorporated new test PNG files into make check.  tests/pngstest-*
+    are changed so that the new test files are divided into 8 groups by
+    gamma and alpha channel.  These tests have considerably better code
+    and pixel-value coverage than contrib/pngsuite; however,coverage is
+    still incomplete (John Bowler).
+  Removed the '--strict' in 1.6 because of the double-gamma-correction
+    warning, updated pngstest-errors.h for the errors detected with the
+    new contrib/testspngs PNG test files (John Bowler).
+
+Version 1.6.19beta04 [October 15, 2015]
+  Worked around rgb-to-gray issues in libpng 1.6.  The previous
+    attempts to ignore the errors in the code aren't quite enough to
+    deal with the 'channel selection' encoding added to libpng 1.7; abort.
+    pngvalid.c is changed to drop this encoding in prior versions.
+  Fixed 'pow' macros in pngvalid.c. It is legal for 'pow' to be a
+    macro, therefore the argument list cannot contain preprocessing
+    directives.  Make sure pow is a function where this happens. This is
+    a minimal safe fix, the issue only arises in non-performance-critical
+    code (bug report by Curtis Leach, fix by John Bowler).
+  Added sPLT support to pngtest.c
+
+Version 1.6.19rc01 [October 23, 2015]
+  No changes.
+
+Version 1.6.19rc02 [October 31, 2015]
+  Prevent setting or writing over-length PLTE chunk (Cosmin Truta).
+  Silently truncate over-length PLTE chunk while reading.
+  Libpng incorrectly calculated the output rowbytes when the application
+    decreased either the number of channels or the bit depth (or both) in
+    a user transform.  This was safe; libpng overallocated buffer space
+   (potentially by quite a lot; up to 4 times the amount required) but,
+   from 1.5.4 on, resulted in a png_error (John Bowler).
+
+Version 1.6.19rc03 [November 3, 2015]
+  Fixed some inconsequential cut-and-paste typos in png_set_cHRM_XYZ_fixed().
+  Clarified COPYRIGHT information to state explicitly that versions
+    are derived from previous versions.
+  Removed much of the long list of previous versions from png.h and
+    libpng.3.
+
+Version 1.6.19rc04 [November 5, 2015]
+  Fixed new bug with CRC error after reading an over-length palette
+    (bug report by Cosmin Truta).
+
+Version 1.6.19 [November 12, 2015]
+  Cleaned up coding style in png_handle_PLTE().
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
@@ -5132,3 +5421,4 @@ to subscribe)
 or to glennrp at users.sourceforge.net
 
 Glenn R-P
+#endif
diff --git a/thirdparty/libpng/LICENSE b/thirdparty/libpng/LICENSE
index f912f6a6..11f6ffe5 100644
--- a/thirdparty/libpng/LICENSE
+++ b/thirdparty/libpng/LICENSE
@@ -10,21 +10,18 @@ this sentence.
 
 This code is released under the libpng license.
 
-libpng versions 1.2.6, August 15, 2004, through 1.6.16, December 22, 2014, are
-Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are
-distributed according to the same disclaimer and license as libpng-1.2.5
-with the following individual added to the list of Contributing Authors
-
-   Cosmin Truta
-
-libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are
-Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
-distributed according to the same disclaimer and license as libpng-1.0.6
-with the following individuals added to the list of Contributing Authors
+libpng versions 1.0.7, July 1, 2000, through 1.6.19, November 12, 2015, are
+Copyright (c) 2000-2002, 2004, 2006-2015 Glenn Randers-Pehrson, are
+derived from libpng-1.0.6, and are distributed according to the same
+disclaimer and license as libpng-1.0.6 with the following individuals
+added to the list of Contributing Authors:
 
    Simon-Pierre Cadieux
    Eric S. Raymond
+   Mans Rullgard
+   Cosmin Truta
    Gilles Vollant
+   James Yu
 
 and with the following additions to the disclaimer:
 
@@ -36,18 +33,20 @@ and with the following additions to the disclaimer:
    the user.
 
 libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
-Copyright (c) 1998, 1999 Glenn Randers-Pehrson, and are
-distributed according to the same disclaimer and license as libpng-0.96,
-with the following individuals added to the list of Contributing Authors:
+Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
+libpng-0.96, and are distributed according to the same disclaimer and
+license as libpng-0.96, with the following individuals added to the list
+of Contributing Authors:
 
    Tom Lane
    Glenn Randers-Pehrson
    Willem van Schaik
 
 libpng versions 0.89, June 1996, through 0.96, May 1997, are
-Copyright (c) 1996, 1997 Andreas Dilger
-Distributed according to the same disclaimer and license as libpng-0.88,
-with the following individuals added to the list of Contributing Authors:
+Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
+and are distributed according to the same disclaimer and license as
+libpng-0.88, with the following individuals added to the list of
+Contributing Authors:
 
    John Bowler
    Kevin Bracey
@@ -57,7 +56,7 @@ with the following individuals added to the list of Contributing Authors:
    Tom Tanner
 
 libpng versions 0.5, May 1995, through 0.88, January 1996, are
-Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
 
 For the purposes of this copyright and license, "Contributing Authors"
 is defined as the following set of individuals:
@@ -80,13 +79,13 @@ Permission is hereby granted to use, copy, modify, and distribute this
 source code, or portions hereof, for any purpose, without fee, subject
 to the following restrictions:
 
-1. The origin of this source code must not be misrepresented.
+  1. The origin of this source code must not be misrepresented.
 
-2. Altered versions must be plainly marked as such and must not
-   be misrepresented as being the original source.
+  2. Altered versions must be plainly marked as such and must not
+     be misrepresented as being the original source.
 
-3. This Copyright notice may not be removed or altered from any
-   source or altered source distribution.
+  3. This Copyright notice may not be removed or altered from any
+     source or altered source distribution.
 
 The Contributing Authors and Group 42, Inc. specifically permit, without
 fee, and encourage the use of this source code as a component to
@@ -94,18 +93,20 @@ supporting the PNG file format in commercial products.  If you use this
 source code in a product, acknowledgment is not required but would be
 appreciated.
 
+END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
 
 A "png_get_copyright" function is available, for convenient use in "about"
 boxes and the like:
 
-   printf("%s",png_get_copyright(NULL));
+   printf("%s", png_get_copyright(NULL));
 
 Also, the PNG logo (in PNG format, of course) is supplied in the
 files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
 
-Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is a
-certification mark of the Open Source Initiative.
+Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is
+a certification mark of the Open Source Initiative. OSI has not addressed
+the additional disclaimers inserted at version 1.0.7.
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-December 22, 2014
+November 12, 2015
diff --git a/thirdparty/libpng/README b/thirdparty/libpng/README
index 8c5b0b2f..17484e0f 100644
--- a/thirdparty/libpng/README
+++ b/thirdparty/libpng/README
@@ -1,4 +1,4 @@
-README for libpng version 1.6.16 - December 22, 2014 (shared library 16.0)
+README for libpng version 1.6.19 - November 12, 2015 (shared library 16.0)
 See the note about version numbers near the top of png.h
 
 See INSTALL for instructions on how to install libpng.
@@ -134,7 +134,7 @@ and ...".  If in doubt, send questions to me.  I'll bounce them
 to others, if necessary.
 
 Please do not send suggestions on how to change PNG.  We have
-been discussing PNG for nineteen years now, and it is official and
+been discussing PNG for twenty years now, and it is official and
 finished.  If you have suggestions for libpng, however, I'll
 gladly listen.  Even if your suggestion is not used immediately,
 it may be used later.
diff --git a/thirdparty/libpng/png.c b/thirdparty/libpng/png.c
index 4d93dfa9..6fcfad72 100644
--- a/thirdparty/libpng/png.c
+++ b/thirdparty/libpng/png.c
@@ -1,8 +1,8 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * Last changed in libpng 1.6.16 [December 22, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.19 [November 12, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -14,7 +14,7 @@
 #include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_16 Your_png_h_is_not_version_1_6_16;
+typedef png_libpng_version_1_6_19 Your_png_h_is_not_version_1_6_19;
 
 /* Tells libpng that we have already handled the first "num_bytes" bytes
  * of the PNG file signature.  If the PNG data is embedded into another
@@ -26,15 +26,20 @@ typedef png_libpng_version_1_6_16 Your_png_h_is_not_version_1_6_16;
 void PNGAPI
 png_set_sig_bytes(png_structrp png_ptr, int num_bytes)
 {
+   unsigned int nb = (unsigned int)num_bytes;
+
    png_debug(1, "in png_set_sig_bytes");
 
    if (png_ptr == NULL)
       return;
 
-   if (num_bytes > 8)
+   if (num_bytes < 0)
+      nb = 0;
+
+   if (nb > 8)
       png_error(png_ptr, "Too many bytes for PNG signature");
 
-   png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
+   png_ptr->sig_bytes = (png_byte)nb;
 }
 
 /* Checks whether the supplied bytes match the PNG signature.  We allow
@@ -101,7 +106,7 @@ png_zfree(voidpf png_ptr, voidpf ptr)
 void /* PRIVATE */
 png_reset_crc(png_structrp png_ptr)
 {
-   /* The cast is safe because the crc is a 32 bit value. */
+   /* The cast is safe because the crc is a 32-bit value. */
    png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
 }
 
@@ -129,7 +134,7 @@ png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length)
    }
 
    /* 'uLong' is defined in zlib.h as unsigned long; this means that on some
-    * systems it is a 64 bit value.  crc32, however, returns 32 bits so the
+    * systems it is a 64-bit value.  crc32, however, returns 32 bits so the
     * following cast is safe.  'uInt' may be no more than 16 bits, so it is
     * necessary to perform a loop here.
     */
@@ -140,8 +145,10 @@ png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length)
       do
       {
          uInt safe_length = (uInt)length;
+#ifndef __COVERITY__
          if (safe_length == 0)
             safe_length = (uInt)-1; /* evil, but safe */
+#endif
 
          crc = crc32(crc, ptr, safe_length);
 
@@ -241,15 +248,15 @@ png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
       create_struct.user_height_max = PNG_USER_HEIGHT_MAX;
 
 #     ifdef PNG_USER_CHUNK_CACHE_MAX
-         /* Added at libpng-1.2.43 and 1.4.0 */
-         create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
+      /* Added at libpng-1.2.43 and 1.4.0 */
+      create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
 #     endif
 
 #     ifdef PNG_USER_CHUNK_MALLOC_MAX
-         /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists
-          * in png_struct regardless.
-          */
-         create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
+      /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists
+       * in png_struct regardless.
+       */
+      create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
 #     endif
 #  endif
 
@@ -273,7 +280,9 @@ png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
 
 #  ifdef PNG_SETJMP_SUPPORTED
       if (!setjmp(create_jmp_buf))
+#  endif
       {
+#  ifdef PNG_SETJMP_SUPPORTED
          /* Temporarily fake out the longjmp information until we have
           * successfully completed this function.  This only works if we have
           * setjmp() support compiled in, but it is safe - this stuff should
@@ -282,8 +291,6 @@ png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
          create_struct.jmp_buf_ptr = &create_jmp_buf;
          create_struct.jmp_buf_size = 0; /*stack allocation*/
          create_struct.longjmp_fn = longjmp;
-#  else
-      {
 #  endif
          /* Call the general version checker (shared with read and write code):
           */
@@ -302,10 +309,10 @@ png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
                create_struct.zstream.opaque = png_ptr;
 
 #              ifdef PNG_SETJMP_SUPPORTED
-                  /* Eliminate the local error handling: */
-                  create_struct.jmp_buf_ptr = NULL;
-                  create_struct.jmp_buf_size = 0;
-                  create_struct.longjmp_fn = 0;
+               /* Eliminate the local error handling: */
+               create_struct.jmp_buf_ptr = NULL;
+               create_struct.jmp_buf_size = 0;
+               create_struct.longjmp_fn = 0;
 #              endif
 
                *png_ptr = create_struct;
@@ -411,6 +418,8 @@ png_info_init_3,(png_infopp ptr_ptr, png_size_t png_info_struct_size),
       free(info_ptr);
       info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL,
          (sizeof *info_ptr)));
+      if (info_ptr == NULL)
+         return;
       *ptr_ptr = info_ptr;
    }
 
@@ -476,9 +485,10 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
    /* Free any tRNS entry */
    if (((mask & PNG_FREE_TRNS) & info_ptr->free_me) != 0)
    {
+      info_ptr->valid &= ~PNG_INFO_tRNS;
       png_free(png_ptr, info_ptr->trans_alpha);
       info_ptr->trans_alpha = NULL;
-      info_ptr->valid &= ~PNG_INFO_tRNS;
+      info_ptr->num_trans = 0;
    }
 #endif
 
@@ -544,20 +554,17 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
 
       else
       {
-         if (info_ptr->splt_palettes_num != 0)
-         {
-            int i;
-
-            for (i = 0; i < info_ptr->splt_palettes_num; i++)
-            {
-               png_free(png_ptr, info_ptr->splt_palettes[i].name);
-               png_free(png_ptr, info_ptr->splt_palettes[i].entries);
-            }
+         int i;
 
-            png_free(png_ptr, info_ptr->splt_palettes);
-            info_ptr->splt_palettes = NULL;
-            info_ptr->splt_palettes_num = 0;
+         for (i = 0; i < info_ptr->splt_palettes_num; i++)
+         {
+            png_free(png_ptr, info_ptr->splt_palettes[i].name);
+            png_free(png_ptr, info_ptr->splt_palettes[i].entries);
          }
+
+         png_free(png_ptr, info_ptr->splt_palettes);
+         info_ptr->splt_palettes = NULL;
+         info_ptr->splt_palettes_num = 0;
          info_ptr->valid &= ~PNG_INFO_sPLT;
       }
    }
@@ -577,15 +584,12 @@ png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
       {
          int i;
 
-         if (info_ptr->unknown_chunks_num != 0)
-         {
-            for (i = 0; i < info_ptr->unknown_chunks_num; i++)
-               png_free(png_ptr, info_ptr->unknown_chunks[i].data);
+         for (i = 0; i < info_ptr->unknown_chunks_num; i++)
+            png_free(png_ptr, info_ptr->unknown_chunks[i].data);
 
-            png_free(png_ptr, info_ptr->unknown_chunks);
-            info_ptr->unknown_chunks = NULL;
-            info_ptr->unknown_chunks_num = 0;
-         }
+         png_free(png_ptr, info_ptr->unknown_chunks);
+         info_ptr->unknown_chunks = NULL;
+         info_ptr->unknown_chunks_num = 0;
       }
    }
 #endif
@@ -666,22 +670,23 @@ png_init_io(png_structrp png_ptr, png_FILE_p fp)
 }
 #  endif
 
-#ifdef PNG_SAVE_INT_32_SUPPORTED
-/* The png_save_int_32 function assumes integers are stored in two's
- * complement format.  If this isn't the case, then this routine needs to
- * be modified to write data in two's complement format.  Note that,
- * the following works correctly even if png_int_32 has more than 32 bits
- * (compare the more complex code required on read for sign extension.)
+#  ifdef PNG_SAVE_INT_32_SUPPORTED
+/* PNG signed integers are saved in 32-bit 2's complement format.  ANSI C-90
+ * defines a cast of a signed integer to an unsigned integer either to preserve
+ * the value, if it is positive, or to calculate:
+ *
+ *     (UNSIGNED_MAX+1) + integer
+ *
+ * Where UNSIGNED_MAX is the appropriate maximum unsigned value, so when the
+ * negative integral value is added the result will be an unsigned value
+ * correspnding to the 2's complement representation.
  */
 void PNGAPI
 png_save_int_32(png_bytep buf, png_int_32 i)
 {
-   buf[0] = (png_byte)((i >> 24) & 0xff);
-   buf[1] = (png_byte)((i >> 16) & 0xff);
-   buf[2] = (png_byte)((i >> 8) & 0xff);
-   buf[3] = (png_byte)(i & 0xff);
+   png_save_uint_32(buf, i);
 }
-#endif
+#  endif
 
 #  ifdef PNG_TIME_RFC1123_SUPPORTED
 /* Convert the supplied time into an RFC 1123 string suitable for use in
@@ -725,6 +730,7 @@ png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime)
       APPEND(':');
       APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
       APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
+      PNG_UNUSED (pos)
 
 #     undef APPEND
 #     undef APPEND_NUMBER
@@ -734,7 +740,7 @@ png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime)
    return 1;
 }
 
-#     if PNG_LIBPNG_VER < 10700
+#    if PNG_LIBPNG_VER < 10700
 /* To do: remove the following from libpng-1.7 */
 /* Original API that uses a private buffer in png_struct.
  * Deprecated because it causes png_struct to carry a spurious temporary
@@ -755,7 +761,7 @@ png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime)
 
    return NULL;
 }
-#     endif
+#    endif /* LIBPNG_VER < 10700 */
 #  endif /* TIME_RFC1123 */
 
 #endif /* READ || WRITE */
@@ -769,14 +775,14 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
    return PNG_STRING_NEWLINE \
-     "libpng version 1.6.16 - December 22, 2014" PNG_STRING_NEWLINE \
-     "Copyright (c) 1998-2014 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
-     "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
-     "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
-     PNG_STRING_NEWLINE;
+      "libpng version 1.6.19 - November 12, 2015" PNG_STRING_NEWLINE \
+      "Copyright (c) 1998-2015 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
+      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
+      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
+      PNG_STRING_NEWLINE;
 #  else
-      return "libpng version 1.6.16 - December 22, 2014\
-      Copyright (c) 1998-2014 Glenn Randers-Pehrson\
+   return "libpng version 1.6.19 - November 12, 2015\
+      Copyright (c) 1998-2015 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
 #  endif
@@ -814,9 +820,9 @@ png_get_header_version(png_const_structrp png_ptr)
 #ifdef __STDC__
    return PNG_HEADER_VERSION_STRING
 #  ifndef PNG_READ_SUPPORTED
-   "     (NO READ SUPPORT)"
+      " (NO READ SUPPORT)"
 #  endif
-   PNG_STRING_NEWLINE;
+      PNG_STRING_NEWLINE;
 #else
    return PNG_HEADER_VERSION_STRING;
 #endif
@@ -872,9 +878,9 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette)
 
    for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
    {
-      palette[i].red = (png_byte)v;
-      palette[i].green = (png_byte)v;
-      palette[i].blue = (png_byte)v;
+      palette[i].red = (png_byte)(v & 0xff);
+      palette[i].green = (png_byte)(v & 0xff);
+      palette[i].blue = (png_byte)(v & 0xff);
    }
 }
 #endif
@@ -947,8 +953,6 @@ png_access_version_number(void)
    return((png_uint_32)PNG_LIBPNG_VER);
 }
 
-
-
 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
 /* Ensure that png_ptr->zstream.msg holds some appropriate error message string.
  * If it doesn't 'ret' is used to set it to something appropriate, even in cases
@@ -1091,10 +1095,10 @@ png_colorspace_set_gamma(png_const_structrp png_ptr,
       errmsg = "gamma value out of range";
 
 #  ifdef PNG_READ_gAMA_SUPPORTED
-      /* Allow the application to set the gamma value more than once */
-      else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
-         (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0)
-         errmsg = "duplicate";
+   /* Allow the application to set the gamma value more than once */
+   else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+      (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0)
+      errmsg = "duplicate";
 #  endif
 
    /* Do nothing if the colorspace is already invalid */
@@ -1135,31 +1139,31 @@ png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr)
          PNG_INFO_iCCP);
 
 #     ifdef PNG_COLORSPACE_SUPPORTED
-         /* Clean up the iCCP profile now if it won't be used. */
-         png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/);
+      /* Clean up the iCCP profile now if it won't be used. */
+      png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/);
 #     else
-         PNG_UNUSED(png_ptr)
+      PNG_UNUSED(png_ptr)
 #     endif
    }
 
    else
    {
 #     ifdef PNG_COLORSPACE_SUPPORTED
-         /* Leave the INFO_iCCP flag set if the pngset.c code has already set
-          * it; this allows a PNG to contain a profile which matches sRGB and
-          * yet still have that profile retrievable by the application.
-          */
-         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) != 0)
-            info_ptr->valid |= PNG_INFO_sRGB;
+      /* Leave the INFO_iCCP flag set if the pngset.c code has already set
+       * it; this allows a PNG to contain a profile which matches sRGB and
+       * yet still have that profile retrievable by the application.
+       */
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) != 0)
+         info_ptr->valid |= PNG_INFO_sRGB;
 
-         else
-            info_ptr->valid &= ~PNG_INFO_sRGB;
+      else
+         info_ptr->valid &= ~PNG_INFO_sRGB;
 
-         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
-            info_ptr->valid |= PNG_INFO_cHRM;
+      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+         info_ptr->valid |= PNG_INFO_cHRM;
 
-         else
-            info_ptr->valid &= ~PNG_INFO_cHRM;
+      else
+         info_ptr->valid &= ~PNG_INFO_cHRM;
 #     endif
 
       if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0)
@@ -1181,7 +1185,7 @@ png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr)
    png_colorspace_sync_info(png_ptr, info_ptr);
 }
 #endif
-#endif
+#endif /* GAMMA */
 
 #ifdef PNG_COLORSPACE_SUPPORTED
 /* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for
@@ -1240,16 +1244,17 @@ png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
 
    /* Check xy and, implicitly, z.  Note that wide gamut color spaces typically
     * have end points with 0 tristimulus values (these are impossible end
-    * points, but they are used to cover the possible colors.)
+    * points, but they are used to cover the possible colors).  We check
+    * xy->whitey against 5, not 0, to avoid a possible integer overflow.
     */
-   if (xy->redx < 0 || xy->redx > PNG_FP_1) return 1;
-   if (xy->redy < 0 || xy->redy > PNG_FP_1-xy->redx) return 1;
+   if (xy->redx   < 0 || xy->redx > PNG_FP_1) return 1;
+   if (xy->redy   < 0 || xy->redy > PNG_FP_1-xy->redx) return 1;
    if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1;
    if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1;
-   if (xy->bluex < 0 || xy->bluex > PNG_FP_1) return 1;
-   if (xy->bluey < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1;
+   if (xy->bluex  < 0 || xy->bluex > PNG_FP_1) return 1;
+   if (xy->bluey  < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1;
    if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1;
-   if (xy->whitey < 0 || xy->whitey > PNG_FP_1-xy->whitex) return 1;
+   if (xy->whitey < 5 || xy->whitey > PNG_FP_1-xy->whitex) return 1;
 
    /* The reverse calculation is more difficult because the original tristimulus
     * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8
@@ -1707,7 +1712,6 @@ png_colorspace_set_chromaticities(png_const_structrp png_ptr,
           */
          colorspace->flags |= PNG_COLORSPACE_INVALID;
          png_error(png_ptr, "internal error checking chromaticities");
-         break;
    }
 
    return 0; /* failed */
@@ -1735,7 +1739,6 @@ png_colorspace_set_endpoints(png_const_structrp png_ptr,
       default:
          colorspace->flags |= PNG_COLORSPACE_INVALID;
          png_error(png_ptr, "internal error checking chromaticities");
-         break;
    }
 
    return 0; /* failed */
@@ -2061,8 +2064,8 @@ png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
    temp = png_get_uint_32(profile+12); /* profile/device class */
    switch (temp)
    {
-      case 0x73636E72: /* 'scnr' */
-      case 0x6D6E7472: /* 'mntr' */
+      case 0x73636e72: /* 'scnr' */
+      case 0x6d6e7472: /* 'mntr' */
       case 0x70727472: /* 'prtr' */
       case 0x73706163: /* 'spac' */
          /* All supported */
@@ -2073,7 +2076,7 @@ png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
          return png_icc_profile_error(png_ptr, colorspace, name, temp,
             "invalid embedded Abstract ICC profile");
 
-      case 0x6C696E6B: /* 'link' */
+      case 0x6c696e6b: /* 'link' */
          /* DeviceLink profiles cannot be interpreted in a non-device specific
           * fashion, if an app uses the AToB0Tag in the profile the results are
           * undefined unless the result is sent to the intended device,
@@ -2083,7 +2086,7 @@ png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
          return png_icc_profile_error(png_ptr, colorspace, name, temp,
             "unexpected DeviceLink ICC profile class");
 
-      case 0x6E6D636C: /* 'nmcl' */
+      case 0x6e6d636c: /* 'nmcl' */
          /* A NamedColor profile is also device specific, however it doesn't
           * contain an AToB0 tag that is open to misinterpretation.  Almost
           * certainly it will fail the tests below.
@@ -2109,8 +2112,8 @@ png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
    temp = png_get_uint_32(profile+20);
    switch (temp)
    {
-      case 0x58595A20: /* 'XYZ ' */
-      case 0x4C616220: /* 'Lab ' */
+      case 0x58595a20: /* 'XYZ ' */
+      case 0x4c616220: /* 'Lab ' */
          break;
 
       default:
@@ -2166,7 +2169,8 @@ png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace,
    return 1; /* success, maybe with warnings */
 }
 
-#if defined(PNG_sRGB_SUPPORTED) && PNG_sRGB_PROFILE_CHECKS >= 0
+#ifdef PNG_sRGB_SUPPORTED
+#if PNG_sRGB_PROFILE_CHECKS >= 0
 /* Information about the known ICC sRGB profiles */
 static const struct
 {
@@ -2279,8 +2283,8 @@ png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
          }
 
          /* Length *and* intent must match */
-         if (length == png_sRGB_checks[i].length &&
-            intent == png_sRGB_checks[i].intent)
+         if (length == (png_uint_32) png_sRGB_checks[i].length &&
+            intent == (png_uint_32) png_sRGB_checks[i].intent)
          {
             /* Now calculate the adler32 if not done already. */
             if (adler == 0)
@@ -2324,8 +2328,8 @@ png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
                    */
                   else if (png_sRGB_checks[i].have_md5 == 0)
                   {
-                     png_chunk_report(png_ptr, "out-of-date sRGB profile with"
-                        " no signature",
+                     png_chunk_report(png_ptr,
+                        "out-of-date sRGB profile with no signature",
                         PNG_CHUNK_WARNING);
                   }
 
@@ -2338,8 +2342,8 @@ png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
           * way.  This probably indicates a data error or uninformed hacking.
           * Fall through to "no match".
           */
-         png_chunk_report(png_ptr, "Not recognizing known sRGB profile that"
-             " has been edited", 
+         png_chunk_report(png_ptr,
+             "Not recognizing known sRGB profile that has been edited", 
              PNG_CHUNK_WARNING);
          break;
 # endif
@@ -2349,9 +2353,8 @@ png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
 
    return 0; /* no match */
 }
-#endif
+#endif /* PNG_sRGB_PROFILE_CHECKS >= 0 */
 
-#ifdef PNG_sRGB_SUPPORTED
 void /* PRIVATE */
 png_icc_set_sRGB(png_const_structrp png_ptr,
    png_colorspacerp colorspace, png_const_bytep profile, uLong adler)
@@ -2365,7 +2368,7 @@ png_icc_set_sRGB(png_const_structrp png_ptr,
       (void)png_colorspace_set_sRGB(png_ptr, colorspace,
          (int)/*already checked*/png_get_uint_32(profile+64));
 }
-#endif /* READ_sRGB */
+#endif /* sRGB */
 
 int /* PRIVATE */
 png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace,
@@ -2457,7 +2460,7 @@ png_colorspace_set_rgb_coefficients(png_structrp png_ptr)
          png_error(png_ptr, "internal error handling cHRM->XYZ");
    }
 }
-#endif
+#endif /* READ_RGB_TO_GRAY */
 
 #endif /* COLORSPACE */
 
@@ -2486,18 +2489,19 @@ png_check_IHDR(png_const_structrp png_ptr,
       png_warning(png_ptr, "Image width is zero in IHDR");
       error = 1;
    }
-   else if (width > PNG_UINT_31_MAX)
+
+   if (width > PNG_UINT_31_MAX)
    {
       png_warning(png_ptr, "Invalid image width in IHDR");
       error = 1;
    }
 
-   else if (png_gt(width,
-                   (PNG_SIZE_MAX >> 3) /* 8-byte RGBA pixels */
-                   - 48                /* big_row_buf hack */
-                   - 1                 /* filter byte */
-                   - 7*8               /* rounding width to multiple of 8 pix */
-                   - 8))               /* extra max_pixel_depth pad */
+   if (png_gt(((width + 7) & (~7)),
+       ((PNG_SIZE_MAX
+           - 48        /* big_row_buf hack */
+           - 1)        /* filter byte */
+           / 8)        /* 8-byte RGBA pixels */
+           - 1))       /* extra max_pixel_depth pad */
    {
       /* The size of the row must be within the limits of this architecture.
        * Because the read code can perform arbitrary transformations the
@@ -2513,17 +2517,15 @@ png_check_IHDR(png_const_structrp png_ptr,
       png_warning(png_ptr, "Image width is too large for this architecture");
       error = 1;
    }
-   else
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (width > png_ptr->user_width_max)
+#else
+   if (width > PNG_USER_WIDTH_MAX)
+#endif
    {
-#     ifdef PNG_SET_USER_LIMITS_SUPPORTED
-      if (width > png_ptr->user_width_max)
-#     else
-      if (width > PNG_USER_WIDTH_MAX)
-#     endif
-      {
-         png_warning(png_ptr, "Image width exceeds user limit in IHDR");
-         error = 1;
-      }
+      png_warning(png_ptr, "Image width exceeds user limit in IHDR");
+      error = 1;
    }
 
    if (height == 0)
@@ -2531,22 +2533,21 @@ png_check_IHDR(png_const_structrp png_ptr,
       png_warning(png_ptr, "Image height is zero in IHDR");
       error = 1;
    }
-   else if (height > PNG_UINT_31_MAX)
+
+   if (height > PNG_UINT_31_MAX)
    {
       png_warning(png_ptr, "Invalid image height in IHDR");
       error = 1;
    }
-   else
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (height > png_ptr->user_height_max)
+#else
+   if (height > PNG_USER_HEIGHT_MAX)
+#endif
    {
-#     ifdef PNG_SET_USER_LIMITS_SUPPORTED
-      if (height > png_ptr->user_height_max)
-#     else
-      if (height > PNG_USER_HEIGHT_MAX)
-#     endif
-      {
-         png_warning(png_ptr, "Image height exceeds user limit in IHDR");
-         error = 1;
-      }
+      png_warning(png_ptr, "Image height exceeds user limit in IHDR");
+      error = 1;
    }
 
    /* Check other values */
@@ -2585,7 +2586,7 @@ png_check_IHDR(png_const_structrp png_ptr,
       error = 1;
    }
 
-#  ifdef PNG_MNG_FEATURES_SUPPORTED
+#ifdef PNG_MNG_FEATURES_SUPPORTED
    /* Accept filter_method 64 (intrapixel differencing) only if
     * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
     * 2. Libpng did not read a PNG signature (this filter_method is only
@@ -2618,13 +2619,13 @@ png_check_IHDR(png_const_structrp png_ptr,
       }
    }
 
-#  else
+#else
    if (filter_type != PNG_FILTER_TYPE_BASE)
    {
       png_warning(png_ptr, "Unknown filter method in IHDR");
       error = 1;
    }
-#  endif
+#endif
 
    if (error == 1)
       png_error(png_ptr, "Invalid IHDR data");
@@ -2850,7 +2851,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
 
       if (fp >= DBL_MIN && fp <= DBL_MAX)
       {
-         int exp_b10;       /* A base 10 exponent */
+         int exp_b10;   /* A base 10 exponent */
          double base;   /* 10^exp_b10 */
 
          /* First extract a base 10 exponent of the number,
@@ -2898,7 +2899,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
           */
 
          {
-            int czero, clead, cdigits;
+            unsigned int czero, clead, cdigits;
             char exponent[10];
 
             /* Allow up to two leading zeros - this will not lengthen
@@ -2928,7 +2929,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
                 * of the loop don't break the number into parts so
                 * that the final digit is rounded.
                 */
-               if (cdigits+czero-clead+1 < (int)precision)
+               if (cdigits+czero+1 < precision+clead)
                   fp = modf(fp, &d);
 
                else
@@ -3034,14 +3035,14 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
                   *ascii++ = (char)(48 + (int)d), ++cdigits;
                }
             }
-            while (cdigits+czero-clead < (int)precision && fp > DBL_MIN);
+            while (cdigits+czero < precision+clead && fp > DBL_MIN);
 
             /* The total output count (max) is now 4+precision */
 
             /* Check for an exponent, if we don't need one we are
              * done and just need to terminate the string.  At
              * this point exp_b10==(-1) is effectively if flag - it got
-             * to '-1' because of the decrement after outputing
+             * to '-1' because of the decrement after outputting
              * the decimal point above (the exponent required is
              * *not* -1!)
              */
@@ -3049,7 +3050,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
             {
                /* The following only happens if we didn't output the
                 * leading zeros above for negative exponent, so this
-                * doest add to the digit requirement.  Note that the
+                * doesn't add to the digit requirement.  Note that the
                 * two zeros here can only be output if the two leading
                 * zeros were *not* output, so this doesn't increase
                 * the output count.
@@ -3102,7 +3103,7 @@ png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
             /* Need another size check here for the exponent digits, so
              * this need not be considered above.
              */
-            if ((int)size > cdigits)
+            if (size > cdigits)
             {
                while (cdigits > 0) *ascii++ = exponent[--cdigits];
 
@@ -3150,7 +3151,7 @@ png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,
 
       /* Avoid overflow here on the minimum integer. */
       if (fp < 0)
-         *ascii++ = 45, --size, num = -fp;
+         *ascii++ = 45, num = -fp;
       else
          num = fp;
 
@@ -3206,7 +3207,7 @@ png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,
    png_error(png_ptr, "ASCII conversion buffer too small");
 }
 #   endif /* FIXED_POINT */
-#endif /* READ_SCAL */
+#endif /* SCAL */
 
 #if defined(PNG_FLOATING_POINT_SUPPORTED) && \
    !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
@@ -3224,7 +3225,7 @@ png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text)
       png_fixed_error(png_ptr, text);
 
 #  ifndef PNG_ERROR_TEXT_SUPPORTED
-      PNG_UNUSED(text)
+   PNG_UNUSED(text)
 #  endif
 
    return (png_fixed_point)r;
@@ -3405,29 +3406,29 @@ png_gamma_significant(png_fixed_point gamma_val)
 #endif
 
 #ifdef PNG_READ_GAMMA_SUPPORTED
-#if defined(PNG_16BIT_SUPPORTED) || !defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+#ifdef PNG_16BIT_SUPPORTED
 /* A local convenience routine. */
 static png_fixed_point
 png_product2(png_fixed_point a, png_fixed_point b)
 {
    /* The required result is 1/a * 1/b; the following preserves accuracy. */
-#    ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
    double r = a * 1E-5;
    r *= b;
    r = floor(r+.5);
 
    if (r <= 2147483647. && r >= -2147483648.)
       return (png_fixed_point)r;
-#    else
+#else
    png_fixed_point res;
 
    if (png_muldiv(&res, a, b, 100000) != 0)
       return res;
-#    endif
+#endif
 
    return 0; /* overflow */
 }
-#endif /* 16BIT || !FLOATING_ARITHMETIC */
+#endif /* 16BIT */
 
 /* The inverse of the above. */
 png_fixed_point
@@ -3435,12 +3436,15 @@ png_reciprocal2(png_fixed_point a, png_fixed_point b)
 {
    /* The required result is 1/a * 1/b; the following preserves accuracy. */
 #ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
-   double r = 1E15/a;
-   r /= b;
-   r = floor(r+.5);
+   if (a != 0 && b != 0)
+   {
+      double r = 1E15/a;
+      r /= b;
+      r = floor(r+.5);
 
-   if (r <= 2147483647. && r >= -2147483648.)
-      return (png_fixed_point)r;
+      if (r <= 2147483647. && r >= -2147483648.)
+         return (png_fixed_point)r;
+   }
 #else
    /* This may overflow because the range of png_fixed_point isn't symmetric,
     * but this API is only used for the product of file and screen gamma so it
@@ -3678,7 +3682,7 @@ png_exp(png_fixed_point x)
    if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
    {
       /* Obtain a 4-bit approximation */
-      png_uint_32 e = png_32bit_exp[(x >> 12) & 0xf];
+      png_uint_32 e = png_32bit_exp[(x >> 12) & 0x0f];
 
       /* Incorporate the low 12 bits - these decrease the returned value by
        * multiplying by a number less than 1 if the bit is set.  The multiplier
@@ -3731,7 +3735,7 @@ png_exp8bit(png_fixed_point lg2)
     * step.
     */
    x -= x >> 8;
-   return (png_byte)((x + 0x7fffffU) >> 24);
+   return (png_byte)(((x + 0x7fffffU) >> 24) & 0xff);
 }
 
 #ifdef PNG_16BIT_SUPPORTED
@@ -3792,7 +3796,7 @@ png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val)
 #     endif
    }
 
-   return (png_byte)value;
+   return (png_byte)(value & 0xff);
 }
 
 #ifdef PNG_16BIT_SUPPORTED
@@ -4014,7 +4018,7 @@ png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable,
 
    else
       for (i=0; i<256; ++i)
-         table[i] = (png_byte)i;
+         table[i] = (png_byte)(i & 0xff);
 }
 
 /* Used from png_read_destroy and below to release the memory used by the gamma
@@ -4154,7 +4158,8 @@ png_build_gamma_table(png_structrp png_ptr, int bit_depth)
       *
       */
      if (sig_bit > 0 && sig_bit < 16U)
-        shift = (png_byte)(16U - sig_bit); /* shift == insignificant bits */
+        /* shift == insignificant bits */
+        shift = (png_byte)((16U - sig_bit) & 0xff);
 
      else
         shift = 0; /* keep all 16 bits */
@@ -4223,7 +4228,7 @@ png_set_option(png_structrp png_ptr, int option, int onoff)
       int setting = (2 + (onoff != 0)) << option;
       int current = png_ptr->options;
 
-      png_ptr->options = (png_byte)((current & ~mask) | setting);
+      png_ptr->options = (png_byte)(((current & ~mask) | setting) & 0xff);
 
       return (current & mask) >> option;
    }
@@ -4239,7 +4244,7 @@ png_set_option(png_structrp png_ptr, int option, int onoff)
  * contrib/tools/makesRGB.c.  The actual sRGB transfer curve defined in the
  * specification (see the article at http://en.wikipedia.org/wiki/SRGB)
  * is used, not the gamma=1/2.2 approximation use elsewhere in libpng.
- * The sRGB to linear table is exact (to the nearest 16 bit linear fraction).
+ * The sRGB to linear table is exact (to the nearest 16-bit linear fraction).
  * The inverse (linear to sRGB) table has accuracies as follows:
  *
  * For all possible (255*65535+1) input values:
diff --git a/thirdparty/libpng/png.h b/thirdparty/libpng/png.h
index 997130d3..c83051b1 100644
--- a/thirdparty/libpng/png.h
+++ b/thirdparty/libpng/png.h
@@ -1,8 +1,9 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.6.16, December 22, 2014
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * libpng version 1.6.19, November 12, 2015
+ *
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -10,229 +11,9 @@
  *
  * Authors and maintainers:
  *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
- *   libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.6.16, December 22, 2014: Glenn
+ *   libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
+ *   libpng versions 0.97, January 1998, through 1.6.19, November 12, 2015: Glenn
  *   See also "Contributing Authors", below.
- *
- * Note about libpng version numbers:
- *
- *   Due to various miscommunications, unforeseen code incompatibilities
- *   and occasional factors outside the authors' control, version numbering
- *   on the library has not always been consistent and straightforward.
- *   The following table summarizes matters since version 0.89c, which was
- *   the first widely used release:
- *
- *    source                 png.h  png.h  shared-lib
- *    version                string   int  version
- *    -------                ------ -----  ----------
- *    0.89c "1.0 beta 3"     0.89      89  1.0.89
- *    0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
- *    0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
- *    0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
- *    0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
- *    0.97c                  0.97      97  2.0.97
- *    0.98                   0.98      98  2.0.98
- *    0.99                   0.99      98  2.0.99
- *    0.99a-m                0.99      99  2.0.99
- *    1.00                   1.00     100  2.1.0 [100 should be 10000]
- *    1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
- *    1.0.1       png.h string is   10001  2.1.0
- *    1.0.1a-e    identical to the  10002  from here on, the shared library
- *    1.0.2       source version)   10002  is 2.V where V is the source code
- *    1.0.2a-b                      10003  version, except as noted.
- *    1.0.3                         10003
- *    1.0.3a-d                      10004
- *    1.0.4                         10004
- *    1.0.4a-f                      10005
- *    1.0.5 (+ 2 patches)           10005
- *    1.0.5a-d                      10006
- *    1.0.5e-r                      10100 (not source compatible)
- *    1.0.5s-v                      10006 (not binary compatible)
- *    1.0.6 (+ 3 patches)           10006 (still binary incompatible)
- *    1.0.6d-f                      10007 (still binary incompatible)
- *    1.0.6g                        10007
- *    1.0.6h                        10007  10.6h (testing xy.z so-numbering)
- *    1.0.6i                        10007  10.6i
- *    1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
- *    1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
- *    1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
- *    1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
- *    1.0.7                    1    10007  (still compatible)
- *    1.0.8beta1-4             1    10008  2.1.0.8beta1-4
- *    1.0.8rc1                 1    10008  2.1.0.8rc1
- *    1.0.8                    1    10008  2.1.0.8
- *    1.0.9beta1-6             1    10009  2.1.0.9beta1-6
- *    1.0.9rc1                 1    10009  2.1.0.9rc1
- *    1.0.9beta7-10            1    10009  2.1.0.9beta7-10
- *    1.0.9rc2                 1    10009  2.1.0.9rc2
- *    1.0.9                    1    10009  2.1.0.9
- *    1.0.10beta1              1    10010  2.1.0.10beta1
- *    1.0.10rc1                1    10010  2.1.0.10rc1
- *    1.0.10                   1    10010  2.1.0.10
- *    1.0.11beta1-3            1    10011  2.1.0.11beta1-3
- *    1.0.11rc1                1    10011  2.1.0.11rc1
- *    1.0.11                   1    10011  2.1.0.11
- *    1.0.12beta1-2            2    10012  2.1.0.12beta1-2
- *    1.0.12rc1                2    10012  2.1.0.12rc1
- *    1.0.12                   2    10012  2.1.0.12
- *    1.1.0a-f                 -    10100  2.1.1.0a-f (branch abandoned)
- *    1.2.0beta1-2             2    10200  2.1.2.0beta1-2
- *    1.2.0beta3-5             3    10200  3.1.2.0beta3-5
- *    1.2.0rc1                 3    10200  3.1.2.0rc1
- *    1.2.0                    3    10200  3.1.2.0
- *    1.2.1beta1-4             3    10201  3.1.2.1beta1-4
- *    1.2.1rc1-2               3    10201  3.1.2.1rc1-2
- *    1.2.1                    3    10201  3.1.2.1
- *    1.2.2beta1-6            12    10202  12.so.0.1.2.2beta1-6
- *    1.0.13beta1             10    10013  10.so.0.1.0.13beta1
- *    1.0.13rc1               10    10013  10.so.0.1.0.13rc1
- *    1.2.2rc1                12    10202  12.so.0.1.2.2rc1
- *    1.0.13                  10    10013  10.so.0.1.0.13
- *    1.2.2                   12    10202  12.so.0.1.2.2
- *    1.2.3rc1-6              12    10203  12.so.0.1.2.3rc1-6
- *    1.2.3                   12    10203  12.so.0.1.2.3
- *    1.2.4beta1-3            13    10204  12.so.0.1.2.4beta1-3
- *    1.0.14rc1               13    10014  10.so.0.1.0.14rc1
- *    1.2.4rc1                13    10204  12.so.0.1.2.4rc1
- *    1.0.14                  10    10014  10.so.0.1.0.14
- *    1.2.4                   13    10204  12.so.0.1.2.4
- *    1.2.5beta1-2            13    10205  12.so.0.1.2.5beta1-2
- *    1.0.15rc1-3             10    10015  10.so.0.1.0.15rc1-3
- *    1.2.5rc1-3              13    10205  12.so.0.1.2.5rc1-3
- *    1.0.15                  10    10015  10.so.0.1.0.15
- *    1.2.5                   13    10205  12.so.0.1.2.5
- *    1.2.6beta1-4            13    10206  12.so.0.1.2.6beta1-4
- *    1.0.16                  10    10016  10.so.0.1.0.16
- *    1.2.6                   13    10206  12.so.0.1.2.6
- *    1.2.7beta1-2            13    10207  12.so.0.1.2.7beta1-2
- *    1.0.17rc1               10    10017  12.so.0.1.0.17rc1
- *    1.2.7rc1                13    10207  12.so.0.1.2.7rc1
- *    1.0.17                  10    10017  12.so.0.1.0.17
- *    1.2.7                   13    10207  12.so.0.1.2.7
- *    1.2.8beta1-5            13    10208  12.so.0.1.2.8beta1-5
- *    1.0.18rc1-5             10    10018  12.so.0.1.0.18rc1-5
- *    1.2.8rc1-5              13    10208  12.so.0.1.2.8rc1-5
- *    1.0.18                  10    10018  12.so.0.1.0.18
- *    1.2.8                   13    10208  12.so.0.1.2.8
- *    1.2.9beta1-3            13    10209  12.so.0.1.2.9beta1-3
- *    1.2.9beta4-11           13    10209  12.so.0.9[.0]
- *    1.2.9rc1                13    10209  12.so.0.9[.0]
- *    1.2.9                   13    10209  12.so.0.9[.0]
- *    1.2.10beta1-7           13    10210  12.so.0.10[.0]
- *    1.2.10rc1-2             13    10210  12.so.0.10[.0]
- *    1.2.10                  13    10210  12.so.0.10[.0]
- *    1.4.0beta1-5            14    10400  14.so.0.0[.0]
- *    1.2.11beta1-4           13    10211  12.so.0.11[.0]
- *    1.4.0beta7-8            14    10400  14.so.0.0[.0]
- *    1.2.11                  13    10211  12.so.0.11[.0]
- *    1.2.12                  13    10212  12.so.0.12[.0]
- *    1.4.0beta9-14           14    10400  14.so.0.0[.0]
- *    1.2.13                  13    10213  12.so.0.13[.0]
- *    1.4.0beta15-36          14    10400  14.so.0.0[.0]
- *    1.4.0beta37-87          14    10400  14.so.14.0[.0]
- *    1.4.0rc01               14    10400  14.so.14.0[.0]
- *    1.4.0beta88-109         14    10400  14.so.14.0[.0]
- *    1.4.0rc02-08            14    10400  14.so.14.0[.0]
- *    1.4.0                   14    10400  14.so.14.0[.0]
- *    1.4.1beta01-03          14    10401  14.so.14.1[.0]
- *    1.4.1rc01               14    10401  14.so.14.1[.0]
- *    1.4.1beta04-12          14    10401  14.so.14.1[.0]
- *    1.4.1                   14    10401  14.so.14.1[.0]
- *    1.4.2                   14    10402  14.so.14.2[.0]
- *    1.4.3                   14    10403  14.so.14.3[.0]
- *    1.4.4                   14    10404  14.so.14.4[.0]
- *    1.5.0beta01-58          15    10500  15.so.15.0[.0]
- *    1.5.0rc01-07            15    10500  15.so.15.0[.0]
- *    1.5.0                   15    10500  15.so.15.0[.0]
- *    1.5.1beta01-11          15    10501  15.so.15.1[.0]
- *    1.5.1rc01-02            15    10501  15.so.15.1[.0]
- *    1.5.1                   15    10501  15.so.15.1[.0]
- *    1.5.2beta01-03          15    10502  15.so.15.2[.0]
- *    1.5.2rc01-03            15    10502  15.so.15.2[.0]
- *    1.5.2                   15    10502  15.so.15.2[.0]
- *    1.5.3beta01-10          15    10503  15.so.15.3[.0]
- *    1.5.3rc01-02            15    10503  15.so.15.3[.0]
- *    1.5.3beta11             15    10503  15.so.15.3[.0]
- *    1.5.3 [omitted]
- *    1.5.4beta01-08          15    10504  15.so.15.4[.0]
- *    1.5.4rc01               15    10504  15.so.15.4[.0]
- *    1.5.4                   15    10504  15.so.15.4[.0]
- *    1.5.5beta01-08          15    10505  15.so.15.5[.0]
- *    1.5.5rc01               15    10505  15.so.15.5[.0]
- *    1.5.5                   15    10505  15.so.15.5[.0]
- *    1.5.6beta01-07          15    10506  15.so.15.6[.0]
- *    1.5.6rc01-03            15    10506  15.so.15.6[.0]
- *    1.5.6                   15    10506  15.so.15.6[.0]
- *    1.5.7beta01-05          15    10507  15.so.15.7[.0]
- *    1.5.7rc01-03            15    10507  15.so.15.7[.0]
- *    1.5.7                   15    10507  15.so.15.7[.0]
- *    1.6.0beta01-40          16    10600  16.so.16.0[.0]
- *    1.6.0rc01-08            16    10600  16.so.16.0[.0]
- *    1.6.0                   16    10600  16.so.16.0[.0]
- *    1.6.1beta01-09          16    10601  16.so.16.1[.0]
- *    1.6.1rc01               16    10601  16.so.16.1[.0]
- *    1.6.1                   16    10601  16.so.16.1[.0]
- *    1.6.2beta01             16    10602  16.so.16.2[.0]
- *    1.6.2rc01-06            16    10602  16.so.16.2[.0]
- *    1.6.2                   16    10602  16.so.16.2[.0]
- *    1.6.3beta01-11          16    10603  16.so.16.3[.0]
- *    1.6.3rc01               16    10603  16.so.16.3[.0]
- *    1.6.3                   16    10603  16.so.16.3[.0]
- *    1.6.4beta01-02          16    10604  16.so.16.4[.0]
- *    1.6.4rc01               16    10604  16.so.16.4[.0]
- *    1.6.4                   16    10604  16.so.16.4[.0]
- *    1.6.5                   16    10605  16.so.16.5[.0]
- *    1.6.6                   16    10606  16.so.16.6[.0]
- *    1.6.7beta01-04          16    10607  16.so.16.7[.0]
- *    1.6.7rc01-03            16    10607  16.so.16.7[.0]
- *    1.6.7                   16    10607  16.so.16.7[.0]
- *    1.6.8beta01-02          16    10608  16.so.16.8[.0]
- *    1.6.8rc01-02            16    10608  16.so.16.8[.0]
- *    1.6.8                   16    10608  16.so.16.8[.0]
- *    1.6.9beta01-04          16    10609  16.so.16.9[.0]
- *    1.6.9rc01-02            16    10609  16.so.16.9[.0]
- *    1.6.9                   16    10609  16.so.16.9[.0]
- *    1.6.10beta01-03         16    10610  16.so.16.10[.0]
- *    1.6.10rc01-03           16    10610  16.so.16.10[.0]
- *    1.6.10                  16    10610  16.so.16.10[.0]
- *    1.6.11beta01-06         16    10611  16.so.16.11[.0]
- *    1.6.11rc01-02           16    10611  16.so.16.11[.0]
- *    1.6.11                  16    10611  16.so.16.11[.0]
- *    1.6.12rc01-03           16    10612  16.so.16.12[.0]
- *    1.6.12                  16    10612  16.so.16.12[.0]
- *    1.6.13beta01-04         16    10613  16.so.16.13[.0]
- *    1.6.13rc01-02           16    10613  16.so.16.13[.0]
- *    1.6.13                  16    10613  16.so.16.13[.0]
- *    1.6.14beta01-07         16    10614  16.so.16.14[.0]
- *    1.6.14rc01-02           16    10614  16.so.16.14[.0]
- *    1.6.14                  16    10614  16.so.16.14[.0]
- *    1.6.15beta01-08         16    10615  16.so.16.15[.0]
- *    1.6.15rc01-03           16    10615  16.so.16.15[.0]
- *    1.6.15                  16    10615  16.so.16.15[.0]
- *    1.6.16beta01-03         16    10616  16.so.16.16[.0]
- *    1.6.16rc01-02           16    10616  16.so.16.16[.0]
- *    1.6.16                  16    10616  16.so.16.16[.0]
- *
- *   Henceforth the source version will match the shared-library major
- *   and minor numbers; the shared-library major version number will be
- *   used for changes in backward compatibility, as it is intended.  The
- *   PNG_LIBPNG_VER macro, which is not used within libpng but is available
- *   for applications, is an unsigned integer of the form xyyzz corresponding
- *   to the source version x.y.z (leading zeros in y and z).  Beta versions
- *   were given the previous public release number plus a letter, until
- *   version 1.0.6j; from then on they were given the upcoming public
- *   release number plus "betaNN" or "rcNN".
- *
- *   Binary incompatibility exists only when applications make direct access
- *   to the info_ptr or png_ptr members through png.h, and the compiled
- *   application is loaded with a different version of the library.
- *
- *   DLLNUM will change each time there are forward or backward changes
- *   in binary compatibility (e.g., when a new feature is added).
- *
- * See libpng-manual.txt or libpng.3 for more information.  The PNG
- * specification is available as a W3C Recommendation and as an ISO
- * Specification, <http://www.w3.org/TR/2003/REC-PNG-20031110/
  */
 
 /*
@@ -243,21 +24,18 @@
  *
  * This code is released under the libpng license.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.6.16, December 22, 2014, are
- * Copyright (c) 2004, 2006-2014 Glenn Randers-Pehrson, and are
- * distributed according to the same disclaimer and license as libpng-1.2.5
- * with the following individual added to the list of Contributing Authors:
- *
- *    Cosmin Truta
- *
- * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
- * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
- * distributed according to the same disclaimer and license as libpng-1.0.6
- * with the following individuals added to the list of Contributing Authors:
+ * libpng versions 1.0.7, July 1, 2000, through 1.6.19, November 12, 2015, are
+ * Copyright (c) 2000-2002, 2004, 2006-2015 Glenn Randers-Pehrson, are
+ * derived from libpng-1.0.6, and are distributed according to the same
+ * disclaimer and license as libpng-1.0.6 with the following individuals
+ * added to the list of Contributing Authors:
  *
  *    Simon-Pierre Cadieux
  *    Eric S. Raymond
+ *    Mans Rullgard
+ *    Cosmin Truta
  *    Gilles Vollant
+ *    James Yu
  *
  * and with the following additions to the disclaimer:
  *
@@ -269,18 +47,20 @@
  *    the user.
  *
  * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
- * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
- * distributed according to the same disclaimer and license as libpng-0.96,
- * with the following individuals added to the list of Contributing Authors:
+ * Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
+ * libpng-0.96, and are distributed according to the same disclaimer and
+ * license as libpng-0.96, with the following individuals added to the list
+ * of Contributing Authors:
  *
  *    Tom Lane
  *    Glenn Randers-Pehrson
  *    Willem van Schaik
  *
  * libpng versions 0.89, June 1996, through 0.96, May 1997, are
- * Copyright (c) 1996, 1997 Andreas Dilger
- * Distributed according to the same disclaimer and license as libpng-0.88,
- * with the following individuals added to the list of Contributing Authors:
+ * Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
+ * and are distributed according to the same disclaimer and license as
+ * libpng-0.88, with the following individuals added to the list of
+ * Contributing Authors:
  *
  *    John Bowler
  *    Kevin Bracey
@@ -290,7 +70,7 @@
  *    Tom Tanner
  *
  * libpng versions 0.5, May 1995, through 0.88, January 1996, are
- * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
  *
  * For the purposes of this copyright and license, "Contributing Authors"
  * is defined as the following set of individuals:
@@ -318,29 +98,32 @@
  *   2. Altered versions must be plainly marked as such and must not
  *      be misrepresented as being the original source.
  *
- *   3. This Copyright notice may not be removed or altered from
- *      any source or altered source distribution.
+ *   3. This Copyright notice may not be removed or altered from any
+ *      source or altered source distribution.
  *
  * The Contributing Authors and Group 42, Inc. specifically permit, without
  * fee, and encourage the use of this source code as a component to
  * supporting the PNG file format in commercial products.  If you use this
  * source code in a product, acknowledgment is not required but would be
  * appreciated.
+ *
+ * END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
  */
 
 /*
  * A "png_get_copyright" function is available, for convenient use in "about"
  * boxes and the like:
  *
- *     printf("%s", png_get_copyright(NULL));
+ *    printf("%s", png_get_copyright(NULL));
  *
  * Also, the PNG logo (in PNG format, of course) is supplied in the
  * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
  */
 
 /*
- * Libpng is OSI Certified Open Source Software.  OSI Certified is a
- * certification mark of the Open Source Initiative.
+ * Libpng is OSI Certified Open Source Software.  OSI Certified Open Source is
+ * a certification mark of the Open Source Initiative. OSI has not addressed
+ * the additional disclaimers inserted at version 1.0.7.
  */
 
 /*
@@ -351,17 +134,92 @@
  * Thanks to Frank J. T. Wojcik for helping with the documentation.
  */
 
+/* Note about libpng version numbers:
+ *
+ *    Due to various miscommunications, unforeseen code incompatibilities
+ *    and occasional factors outside the authors' control, version numbering
+ *    on the library has not always been consistent and straightforward.
+ *    The following table summarizes matters since version 0.89c, which was
+ *    the first widely used release:
+ *
+ *    source                 png.h  png.h  shared-lib
+ *    version                string   int  version
+ *    -------                ------ -----  ----------
+ *    0.89c "1.0 beta 3"     0.89      89  1.0.89
+ *    0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
+ *    0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
+ *    0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
+ *    0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
+ *    0.97c                  0.97      97  2.0.97
+ *    0.98                   0.98      98  2.0.98
+ *    0.99                   0.99      98  2.0.99
+ *    0.99a-m                0.99      99  2.0.99
+ *    1.00                   1.00     100  2.1.0 [100 should be 10000]
+ *    1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
+ *    1.0.1       png.h string is   10001  2.1.0
+ *    1.0.1a-e    identical to the  10002  from here on, the shared library
+ *    1.0.2       source version)   10002  is 2.V where V is the source code
+ *    1.0.2a-b                      10003  version, except as noted.
+ *    1.0.3                         10003
+ *    1.0.3a-d                      10004
+ *    1.0.4                         10004
+ *    1.0.4a-f                      10005
+ *    1.0.5 (+ 2 patches)           10005
+ *    1.0.5a-d                      10006
+ *    1.0.5e-r                      10100 (not source compatible)
+ *    1.0.5s-v                      10006 (not binary compatible)
+ *    1.0.6 (+ 3 patches)           10006 (still binary incompatible)
+ *    1.0.6d-f                      10007 (still binary incompatible)
+ *    1.0.6g                        10007
+ *    1.0.6h                        10007  10.6h (testing xy.z so-numbering)
+ *    1.0.6i                        10007  10.6i
+ *    1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
+ *    1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
+ *    1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
+ *    1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
+ *    1.0.7                    1    10007  (still compatible)
+ *    ...
+ *    1.0.19                  10    10019  10.so.0.19[.0]
+ *    ...
+ *    1.2.53                  13    10253  12.so.0.53[.0]
+ *    ...
+ *    1.5.23                  15    10523  15.so.15.23[.0]
+ *    ...
+ *    1.6.19                  16    10619  16.so.16.19[.0]
+ *
+ *    Henceforth the source version will match the shared-library major
+ *    and minor numbers; the shared-library major version number will be
+ *    used for changes in backward compatibility, as it is intended.  The
+ *    PNG_LIBPNG_VER macro, which is not used within libpng but is available
+ *    for applications, is an unsigned integer of the form xyyzz corresponding
+ *    to the source version x.y.z (leading zeros in y and z).  Beta versions
+ *    were given the previous public release number plus a letter, until
+ *    version 1.0.6j; from then on they were given the upcoming public
+ *    release number plus "betaNN" or "rcNN".
+ *
+ *    Binary incompatibility exists only when applications make direct access
+ *    to the info_ptr or png_ptr members through png.h, and the compiled
+ *    application is loaded with a different version of the library.
+ *
+ *    DLLNUM will change each time there are forward or backward changes
+ *    in binary compatibility (e.g., when a new feature is added).
+ *
+ * See libpng.txt or libpng.3 for more information.  The PNG specification
+ * is available as a W3C Recommendation and as an ISO Specification,
+ * <http://www.w3.org/TR/2003/REC-PNG-20031110/
+ */
+
 /*
  * Y2K compliance in libpng:
  * =========================
  *
- *    December 22, 2014
+ *    November 12, 2015
  *
  *    Since the PNG Development group is an ad-hoc body, we can't make
  *    an official declaration.
  *
  *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.6.16 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.19 are Y2K compliant.  It is my belief that
  *    earlier versions were also Y2K compliant.
  *
  *    Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -423,9 +281,9 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.6.16"
+#define PNG_LIBPNG_VER_STRING "1.6.19"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.6.16 - December 22, 2014\n"
+     " libpng version 1.6.19 - November 12, 2015\n"
 
 #define PNG_LIBPNG_VER_SONUM   16
 #define PNG_LIBPNG_VER_DLLNUM  16
@@ -433,7 +291,7 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   6
-#define PNG_LIBPNG_VER_RELEASE 16
+#define PNG_LIBPNG_VER_RELEASE 19
 
 /* This should match the numeric part of the final component of
  * PNG_LIBPNG_VER_STRING, omitting any leading zero:
@@ -464,7 +322,7 @@
  * version 1.0.0 was mis-numbered 100 instead of 10000).  From
  * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release
  */
-#define PNG_LIBPNG_VER 10616 /* 1.6.16 */
+#define PNG_LIBPNG_VER 10619 /* 1.6.19 */
 
 /* Library configuration: these options cannot be changed after
  * the library has been built.
@@ -521,17 +379,22 @@ extern "C" {
 
 /* This file is arranged in several sections:
  *
- * 1. Any configuration options that can be specified by for the application
+ * 1. [omitted]
+ * 2. Any configuration options that can be specified by for the application
  *    code when it is built.  (Build time configuration is in pnglibconf.h)
- * 2. Type definitions (base types are defined in pngconf.h), structure
+ * 3. Type definitions (base types are defined in pngconf.h), structure
  *    definitions.
- * 3. Exported library functions.
- * 4. Simplified API.
+ * 4. Exported library functions.
+ * 5. Simplified API.
+ * 6. Implementation options.
  *
  * The library source code has additional files (principally pngpriv.h) that
  * allow configuration of the library.
  */
-/* Section 1: run time configuration
+
+/* Section 1: [omitted] */
+
+/* Section 2: run time configuration
  * See pnglibconf.h for build time configuration
  *
  * Run time configuration allows the application to choose between
@@ -561,7 +424,7 @@ extern "C" {
  * Otherwise the calls are mapped to png_error.
  */
 
-/* Section 2: type definitions, including structures and compile time
+/* Section 3: type definitions, including structures and compile time
  * constants.
  * See pngconf.h for base types that vary by machine/system
  */
@@ -569,7 +432,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef char* png_libpng_version_1_6_16;
+typedef char* png_libpng_version_1_6_19;
 
 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
  *
@@ -885,7 +748,9 @@ typedef png_unknown_chunk * * png_unknown_chunkpp;
 #define PNG_INFO_iCCP 0x1000   /* ESR, 1.0.6 */
 #define PNG_INFO_sPLT 0x2000   /* ESR, 1.0.6 */
 #define PNG_INFO_sCAL 0x4000   /* ESR, 1.0.6 */
+#if INT_MAX >= 0x8000 /* else this might break */
 #define PNG_INFO_IDAT 0x8000   /* ESR, 1.0.6 */
+#endif
 
 /* This is used for the transformation routines, as some of them
  * change these values for the row.  It also should enable using
@@ -989,7 +854,9 @@ PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
 #define PNG_TRANSFORM_GRAY_TO_RGB   0x2000      /* read only */
 /* Added to libpng-1.5.4 */
 #define PNG_TRANSFORM_EXPAND_16     0x4000      /* read only */
+#if INT_MAX >= 0x8000 /* else this might break */
 #define PNG_TRANSFORM_SCALE_16      0x8000      /* read only */
+#endif
 
 /* Flags for MNG supported features */
 #define PNG_FLAG_MNG_EMPTY_PLTE     0x01
@@ -1006,7 +873,7 @@ typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
     png_alloc_size_t));
 typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
 
-/* Section 3: exported functions
+/* Section 4: exported functions
  * Here are the function definitions most commonly used.  This is not
  * the place to find out how to use libpng.  See libpng-manual.txt for the
  * full explanation, see example.c for the summary.  This just provides
@@ -1379,13 +1246,13 @@ PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
 #endif
 
 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
-/* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
+/* Add a filler byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
 PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
     int flags));
 /* The values of the PNG_FILLER_ defines should NOT be changed */
 #  define PNG_FILLER_BEFORE 0
 #  define PNG_FILLER_AFTER 1
-/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
+/* Add an alpha byte to 8-bit or 16-bit Gray or 24-bit or 48-bit RGB images. */
 PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
     png_uint_32 filler, int flags));
 #endif /* READ_FILLER || WRITE_FILLER */
@@ -1578,6 +1445,7 @@ PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
 #define PNG_CRC_QUIET_USE     4  /* quiet/use data      quiet/use data    */
 #define PNG_CRC_NO_CHANGE     5  /* use current value   use current value */
 
+#ifdef PNG_WRITE_SUPPORTED
 /* These functions give the user control over the scan-line filtering in
  * libpng and the compression methods used by zlib.  These functions are
  * mainly useful for testing, as the defaults should work with most users.
@@ -1591,6 +1459,7 @@ PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
  */
 PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
     int filters));
+#endif /* WRITE */
 
 /* Flags for png_set_filter() to say which filters to use.  The flags
  * are chosen so that they don't conflict with real filter types
@@ -1616,35 +1485,8 @@ PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
 #define PNG_FILTER_VALUE_PAETH 4
 #define PNG_FILTER_VALUE_LAST  5
 
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
-/* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
- * defines, either the default (minimum-sum-of-absolute-differences), or
- * the experimental method (weighted-minimum-sum-of-absolute-differences).
- *
- * Weights are factors >= 1.0, indicating how important it is to keep the
- * filter type consistent between rows.  Larger numbers mean the current
- * filter is that many times as likely to be the same as the "num_weights"
- * previous filters.  This is cumulative for each previous row with a weight.
- * There needs to be "num_weights" values in "filter_weights", or it can be
- * NULL if the weights aren't being specified.  Weights have no influence on
- * the selection of the first row filter.  Well chosen weights can (in theory)
- * improve the compression for a given image.
- *
- * Costs are factors >= 1.0 indicating the relative decoding costs of a
- * filter type.  Higher costs indicate more decoding expense, and are
- * therefore less likely to be selected over a filter with lower computational
- * costs.  There needs to be a value in "filter_costs" for each valid filter
- * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
- * setting the costs.  Costs try to improve the speed of decompression without
- * unduly increasing the compressed image size.
- *
- * A negative weight or cost indicates the default value is to be used, and
- * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
- * The default values for both weights and costs are currently 1.0, but may
- * change if good general weighting/cost heuristics can be found.  If both
- * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
- * to the UNWEIGHTED method, but with added encoding time/computation.
- */
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
 PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
     int heuristic_method, int num_weights, png_const_doublep filter_weights,
     png_const_doublep filter_costs))
@@ -1654,15 +1496,12 @@ PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
     png_const_fixed_point_p filter_costs))
 #endif /* WRITE_WEIGHTED_FILTER */
 
-/* Heuristic used for row filter selection.  These defines should NOT be
- * changed.
- */
+/* The following are no longer used and will be removed from libpng-1.7: */
 #define PNG_FILTER_HEURISTIC_DEFAULT    0  /* Currently "UNWEIGHTED" */
 #define PNG_FILTER_HEURISTIC_UNWEIGHTED 1  /* Used by libpng < 0.95 */
 #define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */
 #define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */
 
-#ifdef PNG_WRITE_SUPPORTED
 /* Set the library compression level.  Currently, valid values range from
  * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
  * (0 - no compression, 9 - "maximal" compression).  Note that tests have
@@ -1670,6 +1509,7 @@ PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
  * for PNG images, and do considerably fewer caclulations.  In the future,
  * these values may not correspond directly to the zlib compression levels.
  */
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
 PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
     int level));
 
@@ -1687,7 +1527,7 @@ PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
 
 PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
     int method));
-#endif
+#endif /* WRITE_CUSTOMIZE_COMPRESSION */
 
 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
 /* Also set zlib parameters for compressing non-IDAT chunks */
@@ -1709,6 +1549,7 @@ PNG_EXPORT(225, void, png_set_text_compression_window_bits,
 PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
     int method));
 #endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+#endif /* WRITE */
 
 /* These next functions are called for input/output, memory, and error
  * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
@@ -1819,7 +1660,7 @@ PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
  *
  * The integer return from the callback function is interpreted thus:
  *
- * negative: An error occured, png_chunk_error will be called.
+ * negative: An error occurred; png_chunk_error will be called.
  *     zero: The chunk was not handled, the chunk will be saved. A critical
  *           chunk will cause an error at this point unless it is to be saved.
  * positive: The chunk was handled, libpng will ignore/discard it.
@@ -2664,26 +2505,28 @@ PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
            * (png_uint_16)(alpha)                         \
            + (png_uint_16)(bg)*(png_uint_16)(255          \
            - (png_uint_16)(alpha)) + 128);                \
-       (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
+       (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); }
 
 #  define png_composite_16(composite, fg, alpha, bg)       \
      { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg)  \
            * (png_uint_32)(alpha)                          \
            + (png_uint_32)(bg)*(65535                      \
            - (png_uint_32)(alpha)) + 32768);               \
-       (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
+       (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); }
 
 #else  /* Standard method using integer division */
 
-#  define png_composite(composite, fg, alpha, bg)                          \
-     (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) +  \
-     (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) +       \
-     127) / 255)
+#  define png_composite(composite, fg, alpha, bg)                        \
+     (composite) =                                                       \
+         (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) +  \
+         (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
+         127) / 255))
 
 #  define png_composite_16(composite, fg, alpha, bg)                         \
-     (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
-     (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) +         \
-     32767) / 65535)
+     (composite) =                                                           \
+         (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
+         (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) +     \
+         32767) / 65535))
 #endif /* READ_COMPOSITE_NODIV */
 
 #ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
@@ -2734,7 +2577,7 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
 
 #  define PNG_get_int_32(buf) \
      ((png_int_32)((*(buf) & 0x80) \
-      ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \
+      ? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
       : (png_int_32)png_get_uint_32(buf)))
 
    /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
@@ -2754,10 +2597,17 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
 #  endif
 #endif
 
-#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
-    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+PNG_EXPORT(242, void, png_set_check_for_invalid_index,
+    (png_structrp png_ptr, int allowed));
+#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
+    png_const_infop info_ptr));
+#  endif
+#endif /* CHECK_FOR_INVALID_INDEX */
+
 /*******************************************************************************
- *  SIMPLIFIED API
+ * Section 5: SIMPLIFIED API
  *******************************************************************************
  *
  * Please read the documentation in libpng-manual.txt (TODO: write said
@@ -2773,8 +2623,9 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
  *
  * To read a PNG file using the simplified API:
  *
- * 1) Declare a 'png_image' structure (see below) on the stack and set the
- *    version field to PNG_IMAGE_VERSION.
+ * 1) Declare a 'png_image' structure (see below) on the stack, set the
+ *    version field to PNG_IMAGE_VERSION and the 'opaque' pointer to NULL
+ *    (this is REQUIRED, your program may crash if you don't do it.)
  * 2) Call the appropriate png_image_begin_read... function.
  * 3) Set the png_image 'format' member to the required sample format.
  * 4) Allocate a buffer for the image and, if required, the color-map.
@@ -2801,6 +2652,9 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
  * when it is being read or defines the in-memory format of an image that you
  * need to write:
  */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
+    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+
 #define PNG_IMAGE_VERSION 1
 
 typedef struct png_control *png_controlp;
@@ -2900,7 +2754,7 @@ typedef struct
  * called to read or write the color-map and set the format correctly for the
  * image data.  Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
  *
- * NOTE: libpng can be built with particular features disabled, if you see
+ * NOTE: libpng can be built with particular features disabled. If you see
  * compiler errors because the definition of one of the following flags has been
  * compiled out it is because libpng does not have the required support.  It is
  * possible, however, for the libpng configuration to enable the format on just
@@ -2912,7 +2766,7 @@ typedef struct
  */
 #define PNG_FORMAT_FLAG_ALPHA    0x01U /* format with an alpha channel */
 #define PNG_FORMAT_FLAG_COLOR    0x02U /* color format: otherwise grayscale */
-#define PNG_FORMAT_FLAG_LINEAR   0x04U /* 2 byte channels else 1 byte */
+#define PNG_FORMAT_FLAG_LINEAR   0x04U /* 2-byte channels else 1-byte */
 #define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
 
 #ifdef PNG_FORMAT_BGR_SUPPORTED
@@ -3199,9 +3053,11 @@ PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
  *
  * With all APIs row_stride is handled as in the read APIs - it is the spacing
  * from one row to the next in component sized units (1 or 2 bytes) and if
- * negative indicates a bottom-up row layout in the buffer.
+ * negative indicates a bottom-up row layout in the buffer.  If row_stride is zero,
+ * libpng will calculate it for you from the image width and number of channels.
  *
- * Note that the write API does not support interlacing or sub-8-bit pixels.
+ * Note that the write API does not support interlacing, sub-8-bit pixels, indexed
+ * PNG (color_type 3) or most ancillary chunks.
  */
 #endif /* STDIO */
 #endif /* SIMPLIFIED_WRITE */
@@ -3210,17 +3066,8 @@ PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
  ******************************************************************************/
 #endif /* SIMPLIFIED_{READ|WRITE} */
 
-#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
-PNG_EXPORT(242, void, png_set_check_for_invalid_index,
-    (png_structrp png_ptr, int allowed));
-#  ifdef PNG_GET_PALETTE_MAX_SUPPORTED
-PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
-    png_const_infop info_ptr));
-#  endif
-#endif /* CHECK_FOR_INVALID_INDEX */
-
 /*******************************************************************************
- *  IMPLEMENTATION OPTIONS
+ * Section 6: IMPLEMENTATION OPTIONS
  *******************************************************************************
  *
  * Support for arbitrary implementation-specific optimizations.  The API allows
diff --git a/thirdparty/libpng/pngconf.h b/thirdparty/libpng/pngconf.h
index 03615f0e..f1b795b4 100644
--- a/thirdparty/libpng/pngconf.h
+++ b/thirdparty/libpng/pngconf.h
@@ -1,9 +1,9 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.6.16,December 22, 2014
+ * libpng version 1.6.19, July 23, 2015
  *
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -11,9 +11,7 @@
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
  *
- */
-
-/* Any machine specific code is near the front of this file, so if you
+ * Any machine specific code is near the front of this file, so if you
  * are configuring libpng for a machine, you may want to read the section
  * starting here down to where it starts to typedef png_color, png_text,
  * and png_info.
@@ -22,26 +20,6 @@
 #ifndef PNGCONF_H
 #define PNGCONF_H
 
-/* To do: Do all of this in scripts/pnglibconf.dfa */
-#ifdef PNG_SAFE_LIMITS_SUPPORTED
-#  ifdef PNG_USER_WIDTH_MAX
-#    undef PNG_USER_WIDTH_MAX
-#    define PNG_USER_WIDTH_MAX 1000000L
-#  endif
-#  ifdef PNG_USER_HEIGHT_MAX
-#    undef PNG_USER_HEIGHT_MAX
-#    define PNG_USER_HEIGHT_MAX 1000000L
-#  endif
-#  ifdef PNG_USER_CHUNK_MALLOC_MAX
-#    undef PNG_USER_CHUNK_MALLOC_MAX
-#    define PNG_USER_CHUNK_MALLOC_MAX 4000000L
-#  endif
-#  ifdef PNG_USER_CHUNK_CACHE_MAX
-#    undef PNG_USER_CHUNK_CACHE_MAX
-#    define PNG_USER_CHUNK_CACHE_MAX 128
-#  endif
-#endif
-
 #ifndef PNG_BUILDING_SYMBOL_TABLE /* else includes may cause problems */
 
 /* From libpng 1.6.0 libpng requires an ANSI X3.159-1989 ("ISOC90") compliant C
@@ -85,7 +63,7 @@
  */
 #define PNG_CONST const /* backward compatibility only */
 
-/* This controls optimization of the reading of 16 and 32 bit values
+/* This controls optimization of the reading of 16-bit and 32-bit values
  * from PNG files.  It can be set on a per-app-file basis - it
  * just changes whether a macro is used when the function is called.
  * The library builder sets the default; if read functions are not
@@ -317,11 +295,11 @@
     * table entries, so we discard it here.  See the .dfn files in the
     * scripts directory.
     */
-#ifndef PNG_EXPORTA
 
-#  define PNG_EXPORTA(ordinal, type, name, args, attributes)\
-      PNG_FUNCTION(PNG_EXPORT_TYPE(type),(PNGAPI name),PNGARG(args), \
-        extern attributes)
+#ifndef PNG_EXPORTA
+#  define PNG_EXPORTA(ordinal, type, name, args, attributes) \
+      PNG_FUNCTION(PNG_EXPORT_TYPE(type), (PNGAPI name), PNGARG(args), \
+      PNG_LINKAGE_API attributes)
 #endif
 
 /* ANSI-C (C90) does not permit a macro to be invoked with an empty argument,
@@ -329,7 +307,7 @@
  */
 #define PNG_EMPTY /*empty list*/
 
-#define PNG_EXPORT(ordinal, type, name, args)\
+#define PNG_EXPORT(ordinal, type, name, args) \
    PNG_EXPORTA(ordinal, type, name, args, PNG_EMPTY)
 
 /* Use PNG_REMOVED to comment out a removed interface. */
@@ -502,7 +480,7 @@
 #if CHAR_BIT == 8 && UCHAR_MAX == 255
    typedef unsigned char png_byte;
 #else
-#  error "libpng requires 8 bit bytes"
+#  error "libpng requires 8-bit bytes"
 #endif
 
 #if INT_MIN == -32768 && INT_MAX == 32767
@@ -510,7 +488,7 @@
 #elif SHRT_MIN == -32768 && SHRT_MAX == 32767
    typedef short png_int_16;
 #else
-#  error "libpng requires a signed 16 bit type"
+#  error "libpng requires a signed 16-bit type"
 #endif
 
 #if UINT_MAX == 65535
@@ -518,7 +496,7 @@
 #elif USHRT_MAX == 65535
    typedef unsigned short png_uint_16;
 #else
-#  error "libpng requires an unsigned 16 bit type"
+#  error "libpng requires an unsigned 16-bit type"
 #endif
 
 #if INT_MIN < -2147483646 && INT_MAX > 2147483646
@@ -526,7 +504,7 @@
 #elif LONG_MIN < -2147483646 && LONG_MAX > 2147483646
    typedef long int png_int_32;
 #else
-#  error "libpng requires a signed 32 bit (or more) type"
+#  error "libpng requires a signed 32-bit (or more) type"
 #endif
 
 #if UINT_MAX > 4294967294
@@ -534,7 +512,7 @@
 #elif ULONG_MAX > 4294967294
    typedef unsigned long int png_uint_32;
 #else
-#  error "libpng requires an unsigned 32 bit (or more) type"
+#  error "libpng requires an unsigned 32-bit (or more) type"
 #endif
 
 /* Prior to 1.6.0 it was possible to disable the use of size_t, 1.6.0, however,
diff --git a/thirdparty/libpng/pngdebug.h b/thirdparty/libpng/pngdebug.h
index b43c59cd..6a01b106 100644
--- a/thirdparty/libpng/pngdebug.h
+++ b/thirdparty/libpng/pngdebug.h
@@ -1,12 +1,11 @@
 
 /* pngdebug.h - Debugging macros for libpng, also used in pngtest.c
  *
+ * Last changed in libpng 1.6.8 [December 19, 2013]
  * Copyright (c) 1998-2013 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
- * Last changed in libpng 1.6.8 [December 19, 2013]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
diff --git a/thirdparty/libpng/pngget.c b/thirdparty/libpng/pngget.c
index fce126cd..743a6a9b 100644
--- a/thirdparty/libpng/pngget.c
+++ b/thirdparty/libpng/pngget.c
@@ -1,8 +1,8 @@
 
 /* pngget.c - retrieval of values from info struct
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -799,14 +799,20 @@ png_get_IHDR(png_const_structrp png_ptr, png_const_inforp info_ptr,
 {
    png_debug1(1, "in %s retrieval function", "IHDR");
 
-   if (png_ptr == NULL || info_ptr == NULL || width == NULL ||
-       height == NULL || bit_depth == NULL || color_type == NULL)
+   if (png_ptr == NULL || info_ptr == NULL)
       return (0);
 
-   *width = info_ptr->width;
-   *height = info_ptr->height;
-   *bit_depth = info_ptr->bit_depth;
-   *color_type = info_ptr->color_type;
+   if (width != NULL)
+       *width = info_ptr->width;
+
+   if (height != NULL)
+       *height = info_ptr->height;
+
+   if (bit_depth != NULL)
+       *bit_depth = info_ptr->bit_depth;
+
+   if (color_type != NULL)
+       *color_type = info_ptr->color_type;
 
    if (compression_type != NULL)
       *compression_type = info_ptr->compression_type;
@@ -1135,21 +1141,21 @@ png_get_compression_buffer_size(png_const_structrp png_ptr)
    if (png_ptr == NULL)
       return 0;
 
-#  ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_SUPPORTED
       if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
-#  endif
+#endif
    {
-#     ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
          return png_ptr->IDAT_read_size;
-#     else
+#else
          return PNG_IDAT_READ_SIZE;
-#     endif
+#endif
    }
 
-#  ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_SUPPORTED
       else
          return png_ptr->zbuffer_size;
-#  endif
+#endif
 }
 
 #ifdef PNG_SET_USER_LIMITS_SUPPORTED
diff --git a/thirdparty/libpng/pnginfo.h b/thirdparty/libpng/pnginfo.h
index 122a90a4..c8c874dd 100644
--- a/thirdparty/libpng/pnginfo.h
+++ b/thirdparty/libpng/pnginfo.h
@@ -1,12 +1,11 @@
 
 /* pnginfo.h - header file for PNG reference library
  *
+ * Last changed in libpng 1.6.1 [March 28, 2013]
  * Copyright (c) 1998-2013 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
- * Last changed in libpng 1.6.1 [March 28, 2013]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
diff --git a/thirdparty/libpng/pnglibconf.h b/thirdparty/libpng/pnglibconf.h
index da3b2292..ff5d156a 100644
--- a/thirdparty/libpng/pnglibconf.h
+++ b/thirdparty/libpng/pnglibconf.h
@@ -1,10 +1,10 @@
-/* libpng 1.6.16 STANDARD API DEFINITION */
+/* libpng 1.6.19 STANDARD API DEFINITION */
 
 /* pnglibconf.h - library build configuration */
 
-/* Libpng version 1.6.16 - December 22, 2014 */
+/* Libpng version 1.6.19 - November 12, 2015 */
 
-/* Copyright (c) 1998-2014 Glenn Randers-Pehrson */
+/* Copyright (c) 1998-2015 Glenn Randers-Pehrson */
 
 /* This code is released under the libpng license. */
 /* For conditions of distribution and use, see the disclaimer */
@@ -97,13 +97,10 @@
 #define PNG_READ_tIME_SUPPORTED
 #define PNG_READ_tRNS_SUPPORTED
 #define PNG_READ_zTXt_SUPPORTED
-/*#undef PNG_SAFE_LIMITS_SUPPORTED*/
 #define PNG_SAVE_INT_32_SUPPORTED
 #define PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
 #define PNG_SEQUENTIAL_READ_SUPPORTED
 #define PNG_SETJMP_SUPPORTED
-#define PNG_SET_CHUNK_CACHE_LIMIT_SUPPORTED
-#define PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
 #define PNG_SET_OPTION_SUPPORTED
 #define PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
 #define PNG_SET_USER_LIMITS_SUPPORTED
@@ -129,6 +126,7 @@
 #define PNG_WRITE_BGR_SUPPORTED
 #define PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
 #define PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+#define PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
 #define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
 #define PNG_WRITE_FILLER_SUPPORTED
 #define PNG_WRITE_FILTER_SUPPORTED
@@ -187,18 +185,24 @@
 /* end of options */
 /* settings */
 #define PNG_API_RULE 0
-#define PNG_COST_SHIFT 3
 #define PNG_DEFAULT_READ_MACROS 1
 #define PNG_GAMMA_THRESHOLD_FIXED 5000
 #define PNG_IDAT_READ_SIZE PNG_ZBUF_SIZE
 #define PNG_INFLATE_BUF_SIZE 1024
+#define PNG_LINKAGE_API extern
+#define PNG_LINKAGE_CALLBACK extern
+#define PNG_LINKAGE_DATA extern
+#define PNG_LINKAGE_FUNCTION extern
 #define PNG_MAX_GAMMA_8 11
 #define PNG_QUANTIZE_BLUE_BITS 5
 #define PNG_QUANTIZE_GREEN_BITS 5
 #define PNG_QUANTIZE_RED_BITS 5
 #define PNG_TEXT_Z_DEFAULT_COMPRESSION (-1)
 #define PNG_TEXT_Z_DEFAULT_STRATEGY 0
-#define PNG_WEIGHT_SHIFT 8
+#define PNG_USER_CHUNK_CACHE_MAX 1000
+#define PNG_USER_CHUNK_MALLOC_MAX 8000000
+#define PNG_USER_HEIGHT_MAX 1000000
+#define PNG_USER_WIDTH_MAX 1000000
 #define PNG_ZBUF_SIZE 8192
 #define PNG_ZLIB_VERNUM 0 /* unknown */
 #define PNG_Z_DEFAULT_COMPRESSION (-1)
diff --git a/thirdparty/libpng/pngmem.c b/thirdparty/libpng/pngmem.c
index d6caf273..45ac5579 100644
--- a/thirdparty/libpng/pngmem.c
+++ b/thirdparty/libpng/pngmem.c
@@ -41,7 +41,7 @@ png_destroy_png_struct(png_structrp png_ptr)
 }
 
 /* Allocate memory.  For reasonable files, size should never exceed
- * 64K.  However, zlib may allocate more then 64K if you don't tell
+ * 64K.  However, zlib may allocate more than 64K if you don't tell
  * it not to.  See zconf.h and png.h for more information.  zlib does
  * need to allocate exactly 64K, so whatever you call here must
  * have the ability to do that.
@@ -77,6 +77,9 @@ png_malloc_base,(png_const_structrp png_ptr, png_alloc_size_t size),
    PNG_UNUSED(png_ptr)
 #endif
 
+   /* Some compilers complain that this is always true.  However, it
+    * can be false when integer overflow happens.
+    */
    if (size > 0 && size <= PNG_SIZE_MAX
 #     ifdef PNG_MAX_MALLOC_64K
          && size <= 65536U
diff --git a/thirdparty/libpng/pngpread.c b/thirdparty/libpng/pngpread.c
index fb40e7db..9f68f990 100644
--- a/thirdparty/libpng/pngpread.c
+++ b/thirdparty/libpng/pngpread.c
@@ -1,8 +1,8 @@
 
 /* pngpread.c - read a png file in push mode
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.18 [July 23, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -19,7 +19,6 @@
 #define PNG_READ_SIG_MODE   0
 #define PNG_READ_CHUNK_MODE 1
 #define PNG_READ_IDAT_MODE  2
-#define PNG_SKIP_MODE       3
 #define PNG_READ_tEXt_MODE  4
 #define PNG_READ_zTXt_MODE  5
 #define PNG_READ_DONE_MODE  6
@@ -78,32 +77,14 @@ png_process_data_pause(png_structrp png_ptr, int save)
 png_uint_32 PNGAPI
 png_process_data_skip(png_structrp png_ptr)
 {
-   png_uint_32 remaining = 0;
-
-   if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE &&
-      png_ptr->skip_length > 0)
-   {
-      /* At the end of png_process_data the buffer size must be 0 (see the loop
-       * above) so we can detect a broken call here:
-       */
-      if (png_ptr->buffer_size != 0)
-         png_error(png_ptr,
-            "png_process_data_skip called inside png_process_data");
-
-      /* If is impossible for there to be a saved buffer at this point -
-       * otherwise we could not be in SKIP mode.  This will also happen if
-       * png_process_skip is called inside png_process_data (but only very
-       * rarely.)
-       */
-      if (png_ptr->save_buffer_size != 0)
-         png_error(png_ptr, "png_process_data_skip called with saved data");
-
-      remaining = png_ptr->skip_length;
-      png_ptr->skip_length = 0;
-      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-   }
-
-   return remaining;
+  /* TODO: Deprecate and remove this API.
+   * Somewhere the implementation of this seems to have been lost,
+   * or abandoned.  It was only to support some internal back-door access
+   * to png_struct) in libpng-1.4.x.
+   */
+   png_app_warning(png_ptr,
+"png_process_data_skip is not implemented in any current version of libpng");
+   return 0;
 }
 
 /* What we do with the incoming data depends on what we were previously
@@ -135,12 +116,6 @@ png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
          break;
       }
 
-      case PNG_SKIP_MODE:
-      {
-         png_push_crc_finish(png_ptr);
-         break;
-      }
-
       default:
       {
          png_ptr->buffer_size = 0;
@@ -159,7 +134,7 @@ void /* PRIVATE */
 png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
 {
    png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */ 
-             num_to_check = 8 - num_checked;
+       num_to_check = 8 - num_checked;
 
    if (png_ptr->buffer_size < num_to_check)
    {
@@ -439,69 +414,6 @@ png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
    png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
 }
 
-void /* PRIVATE */
-png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip)
-{
-   png_ptr->process_mode = PNG_SKIP_MODE;
-   png_ptr->skip_length = skip;
-}
-
-void /* PRIVATE */
-png_push_crc_finish(png_structrp png_ptr)
-{
-   if (png_ptr->skip_length != 0 && png_ptr->save_buffer_size != 0)
-   {
-      png_size_t save_size = png_ptr->save_buffer_size;
-      png_uint_32 skip_length = png_ptr->skip_length;
-
-      /* We want the smaller of 'skip_length' and 'save_buffer_size', but
-       * they are of different types and we don't know which variable has the
-       * fewest bits.  Carefully select the smaller and cast it to the type of
-       * the larger - this cannot overflow.  Do not cast in the following test
-       * - it will break on either 16 or 64 bit platforms.
-       */
-      if (skip_length < save_size)
-         save_size = (png_size_t)skip_length;
-
-      else
-         skip_length = (png_uint_32)save_size;
-
-      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
-
-      png_ptr->skip_length -= skip_length;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->save_buffer_size -= save_size;
-      png_ptr->save_buffer_ptr += save_size;
-   }
-   if (png_ptr->skip_length != 0 && png_ptr->current_buffer_size != 0)
-   {
-      png_size_t save_size = png_ptr->current_buffer_size;
-      png_uint_32 skip_length = png_ptr->skip_length;
-
-      /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
-       * the same problem exists as above and the same solution.
-       */
-      if (skip_length < save_size)
-         save_size = (png_size_t)skip_length;
-
-      else
-         skip_length = (png_uint_32)save_size;
-
-      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
-
-      png_ptr->skip_length -= skip_length;
-      png_ptr->buffer_size -= save_size;
-      png_ptr->current_buffer_size -= save_size;
-      png_ptr->current_buffer_ptr += save_size;
-   }
-   if (png_ptr->skip_length == 0)
-   {
-      PNG_PUSH_SAVE_BUFFER_IF_LT(4)
-      png_crc_finish(png_ptr, 0);
-      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
-   }
-}
-
 void PNGCBAPI
 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
 {
@@ -584,13 +496,11 @@ png_push_save_buffer(png_structrp png_ptr)
       if (png_ptr->save_buffer == NULL)
       {
          png_free(png_ptr, old_buffer);
-         old_buffer = NULL;
          png_error(png_ptr, "Insufficient memory for save_buffer");
       }
 
       memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
       png_free(png_ptr, old_buffer);
-      old_buffer = NULL;
       png_ptr->save_buffer_max = new_max;
    }
    if (png_ptr->current_buffer_size)
@@ -653,7 +563,7 @@ png_push_read_IDAT(png_structrp png_ptr)
        * are of different types and we don't know which variable has the fewest
        * bits.  Carefully select the smaller and cast it to the type of the
        * larger - this cannot overflow.  Do not cast in the following test - it
-       * will break on either 16 or 64 bit platforms.
+       * will break on either 16-bit or 64-bit platforms.
        */
       if (idat_size < save_size)
          save_size = (png_size_t)idat_size;
@@ -696,6 +606,7 @@ png_push_read_IDAT(png_structrp png_ptr)
       png_ptr->current_buffer_size -= save_size;
       png_ptr->current_buffer_ptr += save_size;
    }
+
    if (png_ptr->idat_size == 0)
    {
       PNG_PUSH_SAVE_BUFFER_IF_LT(4)
@@ -726,7 +637,7 @@ png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
     * or the stream marked as finished.
     */
    while (png_ptr->zstream.avail_in > 0 &&
-      !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
+      (png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
    {
       int ret;
 
@@ -1036,6 +947,7 @@ png_push_process_row(png_structrp png_ptr)
       }
    }
    else
+#endif
    {
       png_push_have_row(png_ptr, png_ptr->row_buf + 1);
       png_read_push_finish_row(png_ptr);
@@ -1045,6 +957,7 @@ png_push_process_row(png_structrp png_ptr)
 void /* PRIVATE */
 png_read_push_finish_row(png_structrp png_ptr)
 {
+#ifdef PNG_READ_INTERLACING_SUPPORTED
    /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
    /* Start of interlace block */
@@ -1069,6 +982,7 @@ png_read_push_finish_row(png_structrp png_ptr)
    if (png_ptr->row_number < png_ptr->num_rows)
       return;
 
+#ifdef PNG_READ_INTERLACING_SUPPORTED
    if (png_ptr->interlaced != 0)
    {
       png_ptr->row_number = 0;
@@ -1103,6 +1017,7 @@ png_read_push_finish_row(png_structrp png_ptr)
 
       } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
    }
+#endif /* READ_INTERLACING */
 }
 
 void /* PRIVATE */
@@ -1127,6 +1042,7 @@ png_push_have_row(png_structrp png_ptr, png_bytep row)
          (int)png_ptr->pass);
 }
 
+#ifdef PNG_READ_INTERLACING_SUPPORTED
 void PNGAPI
 png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
     png_const_bytep new_row)
@@ -1141,6 +1057,7 @@ png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
    if (new_row != NULL)
       png_combine_row(png_ptr, old_row, 1/*blocky display*/);
 }
+#endif /* READ_INTERLACING */
 
 void PNGAPI
 png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
diff --git a/thirdparty/libpng/pngpriv.h b/thirdparty/libpng/pngpriv.h
index cbd66dec..c466d4bf 100644
--- a/thirdparty/libpng/pngpriv.h
+++ b/thirdparty/libpng/pngpriv.h
@@ -1,13 +1,11 @@
 
 /* pngpriv.h - private declarations for use inside libpng
  *
- * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.18 [July 23, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
- * Last changed in libpng 1.6.10 [March 6, 1014]]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
@@ -120,8 +118,12 @@
     * to compile with an appropriate #error if ALIGNED_MEMORY has been turned
     * off.
     *
-    * Note that gcc-4.9 defines __ARM_NEON instead of __ARM_NEON__, so we
-    * check both variants.
+    * Note that gcc-4.9 defines __ARM_NEON instead of the deprecated
+    * __ARM_NEON__, so we check both variants.
+    *
+    * To disable ARM_NEON optimizations entirely, and skip compiling the
+    * associated assembler code, pass --enable-arm-neon=no to configure
+    * or put -DPNG_ARM_NEON_OPT=0 in CPPFLAGS.
     */
 #  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
    defined(PNG_ALIGNED_MEMORY_SUPPORTED)
@@ -250,17 +252,18 @@
  * always be used to declare an extern data or function object in this file.
  */
 #ifndef PNG_INTERNAL_DATA
-#  define PNG_INTERNAL_DATA(type, name, array) extern type name array
+#  define PNG_INTERNAL_DATA(type, name, array) PNG_LINKAGE_DATA type name array
 #endif
 
 #ifndef PNG_INTERNAL_FUNCTION
 #  define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
-      extern PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
+      PNG_LINKAGE_FUNCTION PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
 #endif
 
 #ifndef PNG_INTERNAL_CALLBACK
 #  define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
-      extern PNG_FUNCTION(type, (PNGCBAPI name), args, PNG_EMPTY attributes)
+      PNG_LINKAGE_CALLBACK PNG_FUNCTION(type, (PNGCBAPI name), args,\
+         PNG_EMPTY attributes)
 #endif
 
 /* If floating or fixed point APIs are disabled they may still be compiled
@@ -298,48 +301,27 @@
 #  define PNG_DLL_EXPORT
 #endif
 
-/* SECURITY and SAFETY:
+/* This is a global switch to set the compilation for an installed system
+ * (a release build).  It can be set for testing debug builds to ensure that
+ * they will compile when the build type is switched to RC or STABLE, the
+ * default is just to use PNG_LIBPNG_BUILD_BASE_TYPE.  Set this in CPPFLAGS
+ * with either:
  *
- * By default libpng is built without any internal limits on image size,
- * individual heap (png_malloc) allocations or the total amount of memory used.
- * If PNG_SAFE_LIMITS_SUPPORTED is defined, however, the limits below are used
- * (unless individually overridden).  These limits are believed to be fairly
- * safe, but builders of secure systems should verify the values against the
- * real system capabilities.
- */
-#ifdef PNG_SAFE_LIMITS_SUPPORTED
-   /* 'safe' limits */
-#  ifndef PNG_USER_WIDTH_MAX
-#     define PNG_USER_WIDTH_MAX 1000000
-#  endif
-#  ifndef PNG_USER_HEIGHT_MAX
-#     define PNG_USER_HEIGHT_MAX 1000000
-#  endif
-#  ifndef PNG_USER_CHUNK_CACHE_MAX
-#     define PNG_USER_CHUNK_CACHE_MAX 128
-#  endif
-#  ifndef PNG_USER_CHUNK_MALLOC_MAX
-#     define PNG_USER_CHUNK_MALLOC_MAX 8000000
-#  endif
-#else
-   /* values for no limits */
-#  ifndef PNG_USER_WIDTH_MAX
-#     define PNG_USER_WIDTH_MAX 0x7fffffff
-#  endif
-#  ifndef PNG_USER_HEIGHT_MAX
-#     define PNG_USER_HEIGHT_MAX 0x7fffffff
-#  endif
-#  ifndef PNG_USER_CHUNK_CACHE_MAX
-#     define PNG_USER_CHUNK_CACHE_MAX 0
-#  endif
-#  ifndef PNG_USER_CHUNK_MALLOC_MAX
-#     define PNG_USER_CHUNK_MALLOC_MAX 0
-#  endif
+ *   -DPNG_RELEASE_BUILD Turns on the release compile path
+ *   -DPNG_RELEASE_BUILD=0 Turns it off
+ * or in your pngusr.h with
+ *   #define PNG_RELEASE_BUILD=1 Turns on the release compile path
+ *   #define PNG_RELEASE_BUILD=0 Turns it off
+ */
+#ifndef PNG_RELEASE_BUILD
+#  define PNG_RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
 #endif
 
-/* Moved to pngpriv.h at libpng-1.5.0 */
-/* NOTE: some of these may have been used in external applications as
- * these definitions were exposed in pngconf.h prior to 1.5.
+/* SECURITY and SAFETY:
+ *
+ * libpng is built with support for internal limits on image dimensions and
+ * memory usage.  These are documented in scripts/pnglibconf.dfa of the
+ * source and recorded in the machine generated header file pnglibconf.h.
  */
 
 /* If you are running on a machine where you cannot allocate more
@@ -582,21 +564,17 @@
 #define PNG_RGB_TO_GRAY_WARN  0x400000
 #define PNG_RGB_TO_GRAY       0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
 #define PNG_ENCODE_ALPHA      0x800000 /* Added to libpng-1.5.4 */
-#define PNG_ADD_ALPHA         0x1000000 /* Added to libpng-1.2.7 */
-#define PNG_EXPAND_tRNS       0x2000000 /* Added to libpng-1.2.9 */
-#define PNG_SCALE_16_TO_8     0x4000000 /* Added to libpng-1.5.4 */
-                       /*   0x8000000 unused */
-                       /*  0x10000000 unused */
-                       /*  0x20000000 unused */
-                       /*  0x40000000 unused */
+#define PNG_ADD_ALPHA        0x1000000 /* Added to libpng-1.2.7 */
+#define PNG_EXPAND_tRNS      0x2000000 /* Added to libpng-1.2.9 */
+#define PNG_SCALE_16_TO_8    0x4000000 /* Added to libpng-1.5.4 */
+                       /*    0x8000000 unused */
+                       /*   0x10000000 unused */
+                       /*   0x20000000 unused */
+                       /*   0x40000000 unused */
 /* Flags for png_create_struct */
 #define PNG_STRUCT_PNG   0x0001
 #define PNG_STRUCT_INFO  0x0002
 
-/* Scaling factor for filter heuristic weighting calculations */
-#define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
-#define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
-
 /* Flags for the png_ptr->flags rather than declaring a byte for each one */
 #define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
 #define PNG_FLAG_ZSTREAM_INITIALIZED      0x0002 /* Added to libpng-1.6.0 */
@@ -687,7 +665,7 @@
 /* The fixed point conversion performs range checking and evaluates
  * its argument multiple times, so must be used with care.  The
  * range checking uses the PNG specification values for a signed
- * 32 bit fixed point value except that the values are deliberately
+ * 32-bit fixed point value except that the values are deliberately
  * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
  * (2^31-1) * 100000). 's' is a string that describes the value being
  * converted.
@@ -780,15 +758,17 @@
  * macro will fail on top-bit-set values because of the sign extension.
  */
 #define PNG_CHUNK_FROM_STRING(s)\
-   PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
+   PNG_U32(0xff & (s)[0], 0xff & (s)[1], 0xff & (s)[2], 0xff & (s)[3])
 
 /* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
  * signed and the argument is a (char[])  This macro will fail miserably on
  * systems where (char) is more than 8 bits.
  */
 #define PNG_STRING_FROM_CHUNK(s,c)\
-   (void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
-   ((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
+   (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
+   ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
+   ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
+   ((char*)(s))[3]=(char)((c & 0xff)))
 
 /* Do the same but terminate with a null character. */
 #define PNG_CSTRING_FROM_CHUNK(s,c)\
@@ -832,7 +812,7 @@
     */
 #endif
 
-/* This is used for 16 bit gamma tables -- only the top level pointers are
+/* This is used for 16-bit gamma tables -- only the top level pointers are
  * const; this could be changed:
  */
 typedef const png_uint_16p * png_const_uint_16pp;
@@ -850,8 +830,9 @@ PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
 PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
 PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
 
-#define PNG_sRGB_FROM_LINEAR(linear) ((png_byte)((png_sRGB_base[(linear)>>15] +\
-   ((((linear)&0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8))
+#define PNG_sRGB_FROM_LINEAR(linear) \
+  ((png_byte)(0xff & ((png_sRGB_base[(linear)>>15] \
+   + ((((linear) & 0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)))
    /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
     * encoded value with maximum error 0.646365.  Note that the input is not a
     * 16-bit value; it has been multiplied by 255! */
@@ -910,7 +891,7 @@ PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
 #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
    defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
 /* Internal array allocator, outputs no error or warning messages on failure,
- * just returns NULL.  
+ * just returns NULL.
  */
 PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
    int nelements, size_t element_size),PNG_ALLOCATED);
@@ -1408,10 +1389,6 @@ PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
 PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
     png_inforp info_ptr),PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_push_crc_skip,(png_structrp png_ptr,
-    png_uint_32 length),PNG_EMPTY);
-PNG_INTERNAL_FUNCTION(void,png_push_crc_finish,(png_structrp png_ptr),
-    PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
     PNG_EMPTY);
 PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
diff --git a/thirdparty/libpng/pngread.c b/thirdparty/libpng/pngread.c
index 87a78915..48aae848 100644
--- a/thirdparty/libpng/pngread.c
+++ b/thirdparty/libpng/pngread.c
@@ -1,8 +1,8 @@
 
 /* pngread.c - read a PNG file
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -63,7 +63,7 @@ png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
          /* In stable builds only warn if an application error can be completely
           * handled.
           */
-#        if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+#        if PNG_RELEASE_BUILD
             png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
 #        endif
 #     endif
@@ -814,8 +814,7 @@ png_read_end(png_structrp png_ptr, png_inforp info_ptr)
          /* Zero length IDATs are legal after the last IDAT has been
           * read, but not after other chunks have been read.
           */
-         if ((length > 0) ||
-             (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
+         if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
             png_benign_error(png_ptr, "Too many IDATs found");
 
          png_crc_finish(png_ptr, length);
@@ -1044,9 +1043,9 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
    /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
     */
    if ((transforms & PNG_TRANSFORM_SCALE_16) != 0)
-     /* Added at libpng-1.5.4. "strip_16" produces the same result that it
-      * did in earlier versions, while "scale_16" is now more accurate.
-      */
+      /* Added at libpng-1.5.4. "strip_16" produces the same result that it
+       * did in earlier versions, while "scale_16" is now more accurate.
+       */
 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
       png_set_scale_16(png_ptr);
 #else
@@ -1210,7 +1209,7 @@ png_read_png(png_structrp png_ptr, png_inforp info_ptr,
 
       for (iptr = 0; iptr < info_ptr->height; iptr++)
          info_ptr->row_pointers[iptr] = png_voidcast(png_bytep,
-            png_malloc(png_ptr, info_ptr->rowbytes));
+             png_malloc(png_ptr, info_ptr->rowbytes));
    }
 
    png_read_image(png_ptr, info_ptr->row_pointers);
@@ -1684,10 +1683,11 @@ decode_gamma(png_image_read_control *display, png_uint_32 value, int encoding)
          value *= 257;
          break;
 
+#ifdef __GNUC__
       default:
          png_error(display->image->opaque->png_ptr,
             "unexpected encoding (internal error)");
-         break;
+#endif
    }
 
    return value;
@@ -1824,6 +1824,7 @@ png_create_colormap_entry(png_image_read_control *display,
             y = (y + 128) >> 8;
             y *= 255;
             y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7);
+            alpha = PNG_DIV257(alpha);
             encoding = P_sRGB;
          }
 
@@ -2286,8 +2287,14 @@ png_image_read_colormap(png_voidp argument)
                      output_processing = PNG_CMAP_NONE;
                      break;
                   }
-
+#ifdef __COVERITY__
+                 /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
+                  * here.
+                  */
+                  back_alpha = 255;
+#else
                   back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
+#endif
                }
 
                /* output_processing means that the libpng-processed row will be
@@ -2412,7 +2419,14 @@ png_image_read_colormap(png_voidp argument)
                 */
                background_index = i;
                png_create_colormap_entry(display, i++, back_r, back_g, back_b,
-                  output_encoding == P_LINEAR ? 65535U : 255U, output_encoding);
+#ifdef __COVERITY__
+                 /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
+                  * here.
+                  */ 255U,
+#else
+                  output_encoding == P_LINEAR ? 65535U : 255U,
+#endif
+                  output_encoding);
 
                /* For non-opaque input composite on the sRGB background - this
                 * requires inverting the encoding for each component.  The input
@@ -2834,10 +2848,6 @@ png_image_read_colormap(png_voidp argument)
 
    switch (data_encoding)
    {
-      default:
-         png_error(png_ptr, "bad data option (internal error)");
-         break;
-
       case P_sRGB:
          /* Change to 8-bit sRGB */
          png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, PNG_GAMMA_sRGB);
@@ -2847,6 +2857,11 @@ png_image_read_colormap(png_voidp argument)
          if (png_ptr->bit_depth > 8)
             png_set_scale_16(png_ptr);
          break;
+
+#ifdef __GNUC__
+      default:
+         png_error(png_ptr, "bad data option (internal error)");
+#endif
    }
 
    if (cmap_entries > 256 || cmap_entries > image->colormap_entries)
@@ -3246,7 +3261,7 @@ png_image_read_composite(png_voidp argument)
       png_uint_32  width = image->width;
       ptrdiff_t    step_row = display->row_bytes;
       unsigned int channels =
-         (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
+          (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
       int pass;
 
       for (pass = 0; pass < passes; ++pass)
@@ -3397,10 +3412,6 @@ png_image_read_background(png_voidp argument)
     */
    switch (info_ptr->bit_depth)
    {
-      default:
-         png_error(png_ptr, "unexpected bit depth");
-         break;
-
       case 8:
          /* 8-bit sRGB gray values with an alpha channel; the alpha channel is
           * to be removed by composing on a background: either the row if
@@ -3618,6 +3629,11 @@ png_image_read_background(png_voidp argument)
             }
          }
          break;
+
+#ifdef __GNUC__
+      default:
+         png_error(png_ptr, "unexpected bit depth");
+#endif
    }
 
    return 1;
diff --git a/thirdparty/libpng/pngrio.c b/thirdparty/libpng/pngrio.c
index 1e98395f..38f7fd49 100644
--- a/thirdparty/libpng/pngrio.c
+++ b/thirdparty/libpng/pngrio.c
@@ -1,8 +1,8 @@
 
 /* pngrio.c - functions for data input
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -26,7 +26,7 @@
  * reads from a file pointer.  Note that this routine sometimes gets called
  * with very small lengths, so you should implement some kind of simple
  * buffering if you are using unbuffered reads.  This should never be asked
- * to read more then 64K on a 16 bit machine.
+ * to read more than 64K on a 16-bit machine.
  */
 void /* PRIVATE */
 png_read_data(png_structrp png_ptr, png_bytep data, png_size_t length)
diff --git a/thirdparty/libpng/pngrtran.c b/thirdparty/libpng/pngrtran.c
index e6fe9fdb..f129ef12 100644
--- a/thirdparty/libpng/pngrtran.c
+++ b/thirdparty/libpng/pngrtran.c
@@ -1,8 +1,8 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.19 [November 12, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -394,7 +394,7 @@ png_set_alpha_mode(png_structrp png_ptr, int mode, double output_gamma)
 /* Dither file to 8-bit.  Supply a palette, the current number
  * of elements in the palette, the maximum number of elements
  * allowed, and a histogram if possible.  If the current number
- * of colors is greater then the maximum number, the palette will be
+ * of colors is greater than the maximum number, the palette will be
  * modified to fit in the maximum number.  "full_quantize" indicates
  * whether we need a quantizing cube set up for RGB images, or if we
  * simply are reducing the number of colors in a paletted image.
@@ -976,7 +976,6 @@ png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
 
       default:
          png_error(png_ptr, "invalid error action to rgb_to_gray");
-         break;
    }
 
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
@@ -1997,7 +1996,7 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
 #     endif
 
 #  else
-      /* No 16 bit support: force chopping 16-bit input down to 8, in this case
+      /* No 16-bit support: force chopping 16-bit input down to 8, in this case
        * the app program can chose if both APIs are available by setting the
        * correct scaling to use.
        */
@@ -2098,10 +2097,10 @@ png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
 defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
    if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
    {
-      if (info_ptr->bit_depth < png_ptr->user_transform_depth)
+      if (png_ptr->user_transform_depth != 0)
          info_ptr->bit_depth = png_ptr->user_transform_depth;
 
-      if (info_ptr->channels < png_ptr->user_transform_channels)
+      if (png_ptr->user_transform_channels != 0)
          info_ptr->channels = png_ptr->user_transform_channels;
    }
 #endif
@@ -2357,7 +2356,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row,
                if (++channel >= channels)
                   channel = 0;
                *bp++ = (png_byte)(value >> 8);
-               *bp++ = (png_byte)(value & 0xff);
+               *bp++ = (png_byte)value;
             }
             break;
          }
@@ -2382,8 +2381,8 @@ png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
 
       while (sp < ep)
       {
-         /* The input is an array of 16 bit components, these must be scaled to
-          * 8 bits each.  For a 16 bit value V the required value (from the PNG
+         /* The input is an array of 16-bit components, these must be scaled to
+          * 8 bits each.  For a 16-bit value V the required value (from the PNG
           * specification) is:
           *
           *    (V * 255) / 65535
@@ -2404,7 +2403,7 @@ png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
           *
           * The approximate differs from the exact answer only when (vlo-vhi) is
           * 128; it then gives a correction of +1 when the exact correction is
-          * 0.  This gives 128 errors.  The exact answer (correct for all 16 bit
+          * 0.  This gives 128 errors.  The exact answer (correct for all 16-bit
           * input values) is:
           *
           *    error = (vlo-vhi+128)*65535 >> 24;
@@ -2662,9 +2661,9 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
    png_uint_32 row_width = row_info->width;
 
 #ifdef PNG_READ_16BIT_SUPPORTED
-   png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
+   png_byte hi_filler = (png_byte)(filler>>8);
 #endif
-   png_byte lo_filler = (png_byte)(filler & 0xff);
+   png_byte lo_filler = (png_byte)filler;
 
    png_debug(1, "in png_do_read_filler");
 
@@ -2715,13 +2714,13 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
             png_bytep dp = sp  + (png_size_t)row_width * 2;
             for (i = 1; i < row_width; i++)
             {
-               *(--dp) = hi_filler;
                *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
             }
-            *(--dp) = hi_filler;
             *(--dp) = lo_filler;
+            *(--dp) = hi_filler;
             row_info->channels = 2;
             row_info->pixel_depth = 32;
             row_info->rowbytes = row_width * 4;
@@ -2736,8 +2735,8 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
             {
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
-               *(--dp) = hi_filler;
                *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
             }
             row_info->channels = 2;
             row_info->pixel_depth = 32;
@@ -2796,8 +2795,8 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
             png_bytep dp = sp  + (png_size_t)row_width * 2;
             for (i = 1; i < row_width; i++)
             {
-               *(--dp) = hi_filler;
                *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
@@ -2805,8 +2804,8 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
             }
-            *(--dp) = hi_filler;
             *(--dp) = lo_filler;
+            *(--dp) = hi_filler;
             row_info->channels = 4;
             row_info->pixel_depth = 64;
             row_info->rowbytes = row_width * 8;
@@ -2825,8 +2824,8 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
-               *(--dp) = hi_filler;
                *(--dp) = lo_filler;
+               *(--dp) = hi_filler;
             }
 
             row_info->channels = 4;
@@ -3087,10 +3086,11 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
             for (i = 0; i < row_width; i++)
             {
                png_uint_16 red, green, blue, w;
+               png_byte hi,lo;
 
-               red   = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
-               green = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
-               blue  = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
+               hi=*(sp)++; lo=*(sp)++; red   = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; blue  = (png_uint_16)((hi << 8) | (lo));
 
                if (red == green && red == blue)
                {
@@ -3104,16 +3104,16 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
 
                else
                {
-                  png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff)
+                  png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red & 0xff)
                       >> png_ptr->gamma_shift][red>>8];
                   png_uint_16 green_1 =
-                      png_ptr->gamma_16_to_1[(green&0xff) >>
+                      png_ptr->gamma_16_to_1[(green & 0xff) >>
                       png_ptr->gamma_shift][green>>8];
-                  png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff)
+                  png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue & 0xff)
                       >> png_ptr->gamma_shift][blue>>8];
                   png_uint_16 gray16  = (png_uint_16)((rc*red_1 + gc*green_1
                       + bc*blue_1 + 16384)>>15);
-                  w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
+                  w = png_ptr->gamma_16_from_1[(gray16 & 0xff) >>
                       png_ptr->gamma_shift][gray16 >> 8];
                   rgb_error |= 1;
                }
@@ -3138,17 +3138,18 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
             for (i = 0; i < row_width; i++)
             {
                png_uint_16 red, green, blue, gray16;
+               png_byte hi,lo;
 
-               red   = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
-               green = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
-               blue  = (png_uint_16)(((*(sp)) << 8) | *(sp + 1)); sp += 2;
+               hi=*(sp)++; lo=*(sp)++; red   = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
+               hi=*(sp)++; lo=*(sp)++; blue  = (png_uint_16)((hi << 8) | (lo));
 
                if (red != green || red != blue)
                   rgb_error |= 1;
 
-               /* From 1.5.5 in the 16 bit case do the accurate conversion even
+               /* From 1.5.5 in the 16-bit case do the accurate conversion even
                 * in the 'fast' case - this is because this is where the code
-                * ends up when handling linear 16 bit data.
+                * ends up when handling linear 16-bit data.
                 */
                gray16  = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
                   15);
@@ -3313,7 +3314,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                         if ((png_uint_16)((*sp >> shift) & 0x0f)
                             == png_ptr->trans_color.gray)
                         {
-                           unsigned int tmp = *sp & (0xf0f >> (4 - shift));
+                           unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
                            tmp |= png_ptr->background.gray << shift;
                            *sp = (png_byte)(tmp & 0xff);
                         }
@@ -3323,7 +3324,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                            unsigned int p = (*sp >> shift) & 0x0f;
                            unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
                               0x0f;
-                           unsigned int tmp = *sp & (0xf0f >> (4 - shift));
+                           unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
                            tmp |= g << shift;
                            *sp = (png_byte)(tmp & 0xff);
                         }
@@ -3349,7 +3350,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                         if ((png_uint_16)((*sp >> shift) & 0x0f)
                             == png_ptr->trans_color.gray)
                         {
-                           unsigned int tmp = *sp & (0xf0f >> (4 - shift));
+                           unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
                            tmp |= png_ptr->background.gray << shift;
                            *sp = (png_byte)(tmp & 0xff);
                         }
@@ -3667,7 +3668,8 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                         if (optimize != 0)
                            w = v;
                         else
-                           w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
+                           w = gamma_16_from_1[(v & 0xff) >>
+                               gamma_shift][v >> 8];
                         *sp = (png_byte)((w >> 8) & 0xff);
                         *(sp + 1) = (png_byte)(w & 0xff);
                      }
@@ -3831,7 +3833,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                         v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
                         png_composite_16(w, v, a, png_ptr->background_1.red);
                         if (optimize == 0)
-                           w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >>
+                           w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
                                 8];
                         *sp = (png_byte)((w >> 8) & 0xff);
                         *(sp + 1) = (png_byte)(w & 0xff);
@@ -3839,7 +3841,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                         v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
                         png_composite_16(w, v, a, png_ptr->background_1.green);
                         if (optimize == 0)
-                           w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >>
+                           w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
                                 8];
 
                         *(sp + 2) = (png_byte)((w >> 8) & 0xff);
@@ -3848,7 +3850,7 @@ png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
                         v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
                         png_composite_16(w, v, a, png_ptr->background_1.blue);
                         if (optimize == 0)
-                           w = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >>
+                           w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
                                 8];
 
                         *(sp + 4) = (png_byte)((w >> 8) & 0xff);
@@ -4457,7 +4459,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
 
                for (i = 0; i < row_width; i++)
                {
-                  if (*sp == gray)
+                  if ((*sp & 0xffU) == gray)
                      *dp-- = 0;
 
                   else
@@ -4475,7 +4477,8 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                dp = row + (row_info->rowbytes << 1) - 1;
                for (i = 0; i < row_width; i++)
                {
-                  if (*(sp - 1) == gray_high && *(sp) == gray_low)
+                  if ((*(sp - 1) & 0xffU) == gray_high &&
+                      (*(sp) & 0xffU) == gray_low)
                   {
                      *dp-- = 0;
                      *dp-- = 0;
@@ -4837,7 +4840,7 @@ png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
       /* Because PNG_COMPOSE does the gamma transform if there is something to
        * do (if there is an alpha channel or transparency.)
        */
-       !((png_ptr->transformations & PNG_COMPOSE) &&
+       !((png_ptr->transformations & PNG_COMPOSE) != 0 &&
        ((png_ptr->num_trans != 0) ||
        (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)) &&
 #endif
diff --git a/thirdparty/libpng/pngrutil.c b/thirdparty/libpng/pngrutil.c
index 4c26be48..ee584a8c 100644
--- a/thirdparty/libpng/pngrutil.c
+++ b/thirdparty/libpng/pngrutil.c
@@ -1,8 +1,8 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.19 [November 12, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -89,7 +89,13 @@ png_get_int_32)(png_const_bytep buf)
       return uval;
 
    uval = (uval ^ 0xffffffff) + 1;  /* 2's complement: -x = ~x+1 */
-   return -(png_int_32)uval;
+   if ((uval & 0x80000000) == 0) /* no overflow */
+       return -(png_int_32)uval;
+   /* The following has to be safe; this function only gets called on PNG data
+    * and if we get here that data is invalid.  0 is the most safe value and
+    * if not then an attacker would surely just generate a PNG with 0 instead.
+    */
+   return 0;
 }
 
 /* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
@@ -98,7 +104,7 @@ png_get_uint_16)(png_const_bytep buf)
 {
    /* ANSI-C requires an int value to accomodate at least 16 bits so this
     * works and allows the compiler not to worry about possible narrowing
-    * on 32 bit systems.  (Pre-ANSI systems did not make integers smaller
+    * on 32-bit systems.  (Pre-ANSI systems did not make integers smaller
     * than 16 bits either.)
     */
    unsigned int val =
@@ -341,7 +347,7 @@ png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
        * are minimal.
        */
       (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
-#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+#if PNG_RELEASE_BUILD
       png_chunk_warning(png_ptr, msg);
       png_ptr->zowner = 0;
 #else
@@ -575,7 +581,7 @@ png_decompress_chunk(png_structrp png_ptr,
     */
    png_alloc_size_t limit = PNG_SIZE_MAX;
 
-# ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
+# ifdef PNG_SET_USER_LIMITS_SUPPORTED
    if (png_ptr->user_chunk_malloc_max > 0 &&
        png_ptr->user_chunk_malloc_max < limit)
       limit = png_ptr->user_chunk_malloc_max;
@@ -670,7 +676,6 @@ png_decompress_chunk(png_structrp png_ptr,
                    * success)
                    */
                   png_free(png_ptr, text);
-                  text = NULL;
 
                   /* This really is very benign, but it's still an error because
                    * the extra space may otherwise be used as a Trojan Horse.
@@ -867,7 +872,7 @@ void /* PRIVATE */
 png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
 {
    png_color palette[PNG_MAX_PALETTE_LENGTH];
-   int num, i;
+   int max_palette_length, num, i;
 #ifdef PNG_POINTER_INDEXING_SUPPORTED
    png_colorp pal_ptr;
 #endif
@@ -928,6 +933,19 @@ png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
    num = (int)length / 3;
 
+   /* If the palette has 256 or fewer entries but is too large for the bit
+    * depth, we don't issue an error, to preserve the behavior of previous
+    * libpng versions. We silently truncate the unused extra palette entries
+    * here.
+    */
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      max_palette_length = (1 << png_ptr->bit_depth);
+   else
+      max_palette_length = PNG_MAX_PALETTE_LENGTH;
+
+   if (num > max_palette_length)
+      num = max_palette_length;
+
 #ifdef PNG_POINTER_INDEXING_SUPPORTED
    for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
    {
@@ -960,7 +978,7 @@ png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
 #endif
    {
-      png_crc_finish(png_ptr, 0);
+      png_crc_finish(png_ptr, (int) length - num * 3);
    }
 
 #ifndef PNG_READ_OPT_PLTE_SUPPORTED
@@ -1147,11 +1165,13 @@ png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
       return;
 
    for (i=0; i<truelen; ++i)
+   {
       if (buf[i] == 0 || buf[i] > sample_depth)
       {
          png_chunk_benign_error(png_ptr, "invalid");
          return;
       }
+   }
 
    if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
    {
@@ -1462,10 +1482,10 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
                                     finished = 1;
 
 #                                   ifdef PNG_sRGB_SUPPORTED
-                                       /* Check for a match against sRGB */
-                                       png_icc_set_sRGB(png_ptr,
-                                          &png_ptr->colorspace, profile,
-                                          png_ptr->zstream.adler);
+                                    /* Check for a match against sRGB */
+                                    png_icc_set_sRGB(png_ptr,
+                                       &png_ptr->colorspace, profile,
+                                       png_ptr->zstream.adler);
 #                                   endif
 
                                     /* Steal the profile for info_ptr. */
@@ -1515,8 +1535,10 @@ png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
                                  else if (size > 0)
                                     errmsg = "truncated";
 
+#ifndef __COVERITY__
                                  else
                                     errmsg = png_ptr->zstream.msg;
+#endif
                               }
 
                               /* else png_icc_check_tag_table output an error */
@@ -1673,8 +1695,8 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
 
    if (dl > max_dl)
    {
-       png_warning(png_ptr, "sPLT chunk too long");
-       return;
+      png_warning(png_ptr, "sPLT chunk too long");
+      return;
    }
 
    new_palette.nentries = (png_int_32)(data_length / entry_size);
@@ -1684,8 +1706,8 @@ png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
 
    if (new_palette.entries == NULL)
    {
-       png_warning(png_ptr, "sPLT chunk requires too much memory");
-       return;
+      png_warning(png_ptr, "sPLT chunk requires too much memory");
+      return;
    }
 
 #ifdef PNG_POINTER_INDEXING_SUPPORTED
@@ -1815,7 +1837,8 @@ png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
          return;
       }
 
-      if (length > png_ptr->num_palette || length > PNG_MAX_PALETTE_LENGTH ||
+      if (length > (unsigned int) png_ptr->num_palette ||
+         length > (unsigned int) PNG_MAX_PALETTE_LENGTH ||
          length == 0)
       {
          png_crc_finish(png_ptr, length);
@@ -1978,7 +2001,8 @@ png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
 
    num = length / 2 ;
 
-   if (num != png_ptr->num_palette || num > PNG_MAX_PALETTE_LENGTH)
+   if (num != (unsigned int) png_ptr->num_palette ||
+       num > (unsigned int) PNG_MAX_PALETTE_LENGTH)
    {
       png_crc_finish(png_ptr, length);
       png_chunk_benign_error(png_ptr, "invalid");
@@ -2713,14 +2737,14 @@ png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
       png_ptr->unknown_chunk.data = NULL;
    }
 
-#  ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
-      if (png_ptr->user_chunk_malloc_max > 0 &&
-          png_ptr->user_chunk_malloc_max < limit)
-         limit = png_ptr->user_chunk_malloc_max;
+#  ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (png_ptr->user_chunk_malloc_max > 0 &&
+       png_ptr->user_chunk_malloc_max < limit)
+      limit = png_ptr->user_chunk_malloc_max;
 
 #  elif PNG_USER_CHUNK_MALLOC_MAX > 0
-      if (PNG_USER_CHUNK_MALLOC_MAX < limit)
-         limit = PNG_USER_CHUNK_MALLOC_MAX;
+   if (PNG_USER_CHUNK_MALLOC_MAX < limit)
+      limit = PNG_USER_CHUNK_MALLOC_MAX;
 #  endif
 
    if (length <= limit)
@@ -2783,7 +2807,7 @@ png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
     */
 #  ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 #     ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
-         keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
+   keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
 #     endif
 #  endif
 
@@ -2792,153 +2816,153 @@ png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
     * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
     */
 #  ifdef PNG_READ_USER_CHUNKS_SUPPORTED
-      /* The user callback takes precedence over the chunk keep value, but the
-       * keep value is still required to validate a save of a critical chunk.
-       */
-      if (png_ptr->read_user_chunk_fn != NULL)
+   /* The user callback takes precedence over the chunk keep value, but the
+    * keep value is still required to validate a save of a critical chunk.
+    */
+   if (png_ptr->read_user_chunk_fn != NULL)
+   {
+      if (png_cache_unknown_chunk(png_ptr, length) != 0)
       {
-         if (png_cache_unknown_chunk(png_ptr, length) != 0)
+         /* Callback to user unknown chunk handler */
+         int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
+            &png_ptr->unknown_chunk);
+
+         /* ret is:
+          * negative: An error occurred; png_chunk_error will be called.
+          *     zero: The chunk was not handled, the chunk will be discarded
+          *           unless png_set_keep_unknown_chunks has been used to set
+          *           a 'keep' behavior for this particular chunk, in which
+          *           case that will be used.  A critical chunk will cause an
+          *           error at this point unless it is to be saved.
+          * positive: The chunk was handled, libpng will ignore/discard it.
+          */
+         if (ret < 0)
+            png_chunk_error(png_ptr, "error in user chunk");
+
+         else if (ret == 0)
          {
-            /* Callback to user unknown chunk handler */
-            int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
-               &png_ptr->unknown_chunk);
-
-            /* ret is:
-             * negative: An error occured, png_chunk_error will be called.
-             *     zero: The chunk was not handled, the chunk will be discarded
-             *           unless png_set_keep_unknown_chunks has been used to set
-             *           a 'keep' behavior for this particular chunk, in which
-             *           case that will be used.  A critical chunk will cause an
-             *           error at this point unless it is to be saved.
-             * positive: The chunk was handled, libpng will ignore/discard it.
+            /* If the keep value is 'default' or 'never' override it, but
+             * still error out on critical chunks unless the keep value is
+             * 'always'  While this is weird it is the behavior in 1.4.12.
+             * A possible improvement would be to obey the value set for the
+             * chunk, but this would be an API change that would probably
+             * damage some applications.
+             *
+             * The png_app_warning below catches the case that matters, where
+             * the application has not set specific save or ignore for this
+             * chunk or global save or ignore.
              */
-            if (ret < 0)
-               png_chunk_error(png_ptr, "error in user chunk");
-
-            else if (ret == 0)
+            if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
             {
-               /* If the keep value is 'default' or 'never' override it, but
-                * still error out on critical chunks unless the keep value is
-                * 'always'  While this is weird it is the behavior in 1.4.12.
-                * A possible improvement would be to obey the value set for the
-                * chunk, but this would be an API change that would probably
-                * damage some applications.
-                *
-                * The png_app_warning below catches the case that matters, where
-                * the application has not set specific save or ignore for this
-                * chunk or global save or ignore.
-                */
-               if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
+#              ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+               if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
                {
-#                 ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
-                     if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
-                     {
-                        png_chunk_warning(png_ptr, "Saving unknown chunk:");
-                        png_app_warning(png_ptr,
-                           "forcing save of an unhandled chunk;"
-                           " please call png_set_keep_unknown_chunks");
-                           /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
-                     }
-#                 endif
-                  keep = PNG_HANDLE_CHUNK_IF_SAFE;
+                  png_chunk_warning(png_ptr, "Saving unknown chunk:");
+                  png_app_warning(png_ptr,
+                     "forcing save of an unhandled chunk;"
+                     " please call png_set_keep_unknown_chunks");
+                     /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
                }
-            }
-
-            else /* chunk was handled */
-            {
-               handled = 1;
-               /* Critical chunks can be safely discarded at this point. */
-               keep = PNG_HANDLE_CHUNK_NEVER;
+#              endif
+               keep = PNG_HANDLE_CHUNK_IF_SAFE;
             }
          }
 
-         else
-            keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
+         else /* chunk was handled */
+         {
+            handled = 1;
+            /* Critical chunks can be safely discarded at this point. */
+            keep = PNG_HANDLE_CHUNK_NEVER;
+         }
       }
 
       else
-         /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
+         keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
+   }
+
+   else
+   /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
 #  endif /* READ_USER_CHUNKS */
 
 #  ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
-      {
-         /* keep is currently just the per-chunk setting, if there was no
-          * setting change it to the global default now (not that this may
-          * still be AS_DEFAULT) then obtain the cache of the chunk if required,
-          * if not simply skip the chunk.
-          */
-         if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
-            keep = png_ptr->unknown_default;
-
-         if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
-            (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
-             PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
-         {
-            if (png_cache_unknown_chunk(png_ptr, length) == 0)
-               keep = PNG_HANDLE_CHUNK_NEVER;
-         }
+   {
+      /* keep is currently just the per-chunk setting, if there was no
+       * setting change it to the global default now (not that this may
+       * still be AS_DEFAULT) then obtain the cache of the chunk if required,
+       * if not simply skip the chunk.
+       */
+      if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
+         keep = png_ptr->unknown_default;
 
-         else
-            png_crc_finish(png_ptr, length);
+      if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
+         (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
+          PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
+      {
+         if (png_cache_unknown_chunk(png_ptr, length) == 0)
+            keep = PNG_HANDLE_CHUNK_NEVER;
       }
+
+      else
+         png_crc_finish(png_ptr, length);
+   }
 #  else
 #     ifndef PNG_READ_USER_CHUNKS_SUPPORTED
 #        error no method to support READ_UNKNOWN_CHUNKS
 #     endif
 
-      {
-         /* If here there is no read callback pointer set and no support is
-          * compiled in to just save the unknown chunks, so simply skip this
-          * chunk.  If 'keep' is something other than AS_DEFAULT or NEVER then
-          * the app has erroneously asked for unknown chunk saving when there
-          * is no support.
-          */
-         if (keep > PNG_HANDLE_CHUNK_NEVER)
-            png_app_error(png_ptr, "no unknown chunk support available");
+   {
+      /* If here there is no read callback pointer set and no support is
+       * compiled in to just save the unknown chunks, so simply skip this
+       * chunk.  If 'keep' is something other than AS_DEFAULT or NEVER then
+       * the app has erroneously asked for unknown chunk saving when there
+       * is no support.
+       */
+      if (keep > PNG_HANDLE_CHUNK_NEVER)
+         png_app_error(png_ptr, "no unknown chunk support available");
 
-         png_crc_finish(png_ptr, length);
-      }
+      png_crc_finish(png_ptr, length);
+   }
 #  endif
 
 #  ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
-      /* Now store the chunk in the chunk list if appropriate, and if the limits
-       * permit it.
-       */
-      if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
-         (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
-          PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
-      {
-#     ifdef PNG_USER_LIMITS_SUPPORTED
-         switch (png_ptr->user_chunk_cache_max)
-         {
-            case 2:
-               png_ptr->user_chunk_cache_max = 1;
-               png_chunk_benign_error(png_ptr, "no space in chunk cache");
-               /* FALL THROUGH */
-            case 1:
-               /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
-                * chunk being skipped, now there will be a hard error below.
-                */
-               break;
-
-            default: /* not at limit */
-               --(png_ptr->user_chunk_cache_max);
-               /* FALL THROUGH */
-            case 0: /* no limit */
-#     endif /* USER_LIMITS */
-               /* Here when the limit isn't reached or when limits are compiled
-                * out; store the chunk.
-                */
-               png_set_unknown_chunks(png_ptr, info_ptr,
-                  &png_ptr->unknown_chunk, 1);
-               handled = 1;
+   /* Now store the chunk in the chunk list if appropriate, and if the limits
+    * permit it.
+    */
+   if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
+      (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
+       PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
+   {
 #     ifdef PNG_USER_LIMITS_SUPPORTED
-               break;
-         }
-#     endif
+      switch (png_ptr->user_chunk_cache_max)
+      {
+         case 2:
+            png_ptr->user_chunk_cache_max = 1;
+            png_chunk_benign_error(png_ptr, "no space in chunk cache");
+            /* FALL THROUGH */
+         case 1:
+            /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
+             * chunk being skipped, now there will be a hard error below.
+             */
+            break;
+
+         default: /* not at limit */
+            --(png_ptr->user_chunk_cache_max);
+            /* FALL THROUGH */
+         case 0: /* no limit */
+#  endif /* USER_LIMITS */
+            /* Here when the limit isn't reached or when limits are compiled
+             * out; store the chunk.
+             */
+            png_set_unknown_chunks(png_ptr, info_ptr,
+               &png_ptr->unknown_chunk, 1);
+            handled = 1;
+#  ifdef PNG_USER_LIMITS_SUPPORTED
+            break;
       }
+#  endif
+   }
 #  else /* no store support: the chunk must be handled by the user callback */
-      PNG_UNUSED(info_ptr)
+   PNG_UNUSED(info_ptr)
 #  endif
 
    /* Regardless of the error handling below the cached data (if any) can be
@@ -3040,13 +3064,13 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
       end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
       end_byte = *end_ptr;
 #     ifdef PNG_READ_PACKSWAP_SUPPORTED
-         if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
-            /* little-endian byte */
-            end_mask = 0xff << end_mask;
+      if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+         /* little-endian byte */
+         end_mask = 0xff << end_mask;
 
-         else /* big-endian byte */
+      else /* big-endian byte */
 #     endif
-         end_mask = 0xff >> end_mask;
+      end_mask = 0xff >> end_mask;
       /* end_mask is now the bits to *keep* from the destination row */
    }
 
@@ -3204,12 +3228,12 @@ png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
          png_uint_32 mask;
 
 #        ifdef PNG_READ_PACKSWAP_SUPPORTED
-            if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
-               mask = MASK(pass, pixel_depth, display, 0);
+         if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+            mask = MASK(pass, pixel_depth, display, 0);
 
-            else
+         else
 #        endif
-            mask = MASK(pass, pixel_depth, display, 1);
+         mask = MASK(pass, pixel_depth, display, 1);
 
          for (;;)
          {
@@ -3810,15 +3834,15 @@ png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
       p = b - c;
       pc = a - c;
 
-#     ifdef PNG_USE_ABS
-         pa = abs(p);
-         pb = abs(pc);
-         pc = abs(p + pc);
-#     else
-         pa = p < 0 ? -p : p;
-         pb = pc < 0 ? -pc : pc;
-         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#     endif
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
 
       /* Find the best predictor, the least of pa, pb, pc favoring the earlier
        * ones in the case of a tie.
@@ -3865,15 +3889,15 @@ png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
       p = b - c;
       pc = a - c;
 
-#     ifdef PNG_USE_ABS
-         pa = abs(p);
-         pb = abs(pc);
-         pc = abs(p + pc);
-#     else
-         pa = p < 0 ? -p : p;
-         pb = pc < 0 ? -pc : pc;
-         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#     endif
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
 
       if (pb < pa) pa = pb, a = b;
       if (pc < pa) a = c;
@@ -4278,18 +4302,18 @@ png_read_start_row(png_structrp png_ptr)
 #ifdef PNG_READ_EXPAND_16_SUPPORTED
    if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
    {
-#     ifdef PNG_READ_EXPAND_SUPPORTED
-         /* In fact it is an error if it isn't supported, but checking is
-          * the safe way.
-          */
-         if ((png_ptr->transformations & PNG_EXPAND) != 0)
-         {
-            if (png_ptr->bit_depth < 16)
-               max_pixel_depth *= 2;
-         }
-         else
-#     endif
-         png_ptr->transformations &= ~PNG_EXPAND_16;
+#  ifdef PNG_READ_EXPAND_SUPPORTED
+      /* In fact it is an error if it isn't supported, but checking is
+       * the safe way.
+       */
+      if ((png_ptr->transformations & PNG_EXPAND) != 0)
+      {
+         if (png_ptr->bit_depth < 16)
+            max_pixel_depth *= 2;
+      }
+      else
+#  endif
+      png_ptr->transformations &= ~PNG_EXPAND_16;
    }
 #endif
 
diff --git a/thirdparty/libpng/pngset.c b/thirdparty/libpng/pngset.c
index 2f1f550d..05a2134d 100644
--- a/thirdparty/libpng/pngset.c
+++ b/thirdparty/libpng/pngset.c
@@ -1,8 +1,8 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.19 [November 12, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -123,12 +123,12 @@ png_set_cHRM_XYZ(png_const_structrp png_ptr, png_inforp info_ptr, double red_X,
       png_fixed(png_ptr, red_X, "cHRM Red X"),
       png_fixed(png_ptr, red_Y, "cHRM Red Y"),
       png_fixed(png_ptr, red_Z, "cHRM Red Z"),
-      png_fixed(png_ptr, green_X, "cHRM Red X"),
-      png_fixed(png_ptr, green_Y, "cHRM Red Y"),
-      png_fixed(png_ptr, green_Z, "cHRM Red Z"),
-      png_fixed(png_ptr, blue_X, "cHRM Red X"),
-      png_fixed(png_ptr, blue_Y, "cHRM Red Y"),
-      png_fixed(png_ptr, blue_Z, "cHRM Red Z"));
+      png_fixed(png_ptr, green_X, "cHRM Green X"),
+      png_fixed(png_ptr, green_Y, "cHRM Green Y"),
+      png_fixed(png_ptr, green_Z, "cHRM Green Z"),
+      png_fixed(png_ptr, blue_X, "cHRM Blue X"),
+      png_fixed(png_ptr, blue_Y, "cHRM Blue Y"),
+      png_fixed(png_ptr, blue_Z, "cHRM Blue Z"));
 }
 #  endif /* FLOATING_POINT */
 
@@ -190,6 +190,7 @@ png_set_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
    if (info_ptr->hist == NULL)
    {
       png_warning(png_ptr, "Insufficient memory for hIST chunk data");
+
       return;
    }
 
@@ -271,7 +272,7 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
    png_debug1(1, "in %s storage function", "pCAL");
 
    if (png_ptr == NULL || info_ptr == NULL || purpose == NULL || units == NULL
-      || (nparams > 0 && params == NULL))
+       || (nparams > 0 && params == NULL))
       return;
 
    length = strlen(purpose) + 1;
@@ -301,6 +302,7 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
    if (info_ptr->pcal_purpose == NULL)
    {
       png_warning(png_ptr, "Insufficient memory for pCAL purpose");
+
       return;
    }
 
@@ -322,6 +324,7 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
    if (info_ptr->pcal_units == NULL)
    {
       png_warning(png_ptr, "Insufficient memory for pCAL units");
+
       return;
    }
 
@@ -333,6 +336,7 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
    if (info_ptr->pcal_params == NULL)
    {
       png_warning(png_ptr, "Insufficient memory for pCAL params");
+
       return;
    }
 
@@ -349,6 +353,7 @@ png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
       if (info_ptr->pcal_params[i] == NULL)
       {
          png_warning(png_ptr, "Insufficient memory for pCAL parameter");
+
          return;
       }
 
@@ -398,6 +403,7 @@ png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
    if (info_ptr->scal_s_width == NULL)
    {
       png_warning(png_ptr, "Memory allocation failed while processing sCAL");
+
       return;
    }
 
@@ -416,6 +422,7 @@ png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
       info_ptr->scal_s_width = NULL;
 
       png_warning(png_ptr, "Memory allocation failed while processing sCAL");
+
       return;
    }
 
@@ -506,12 +513,17 @@ png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
     png_const_colorp palette, int num_palette)
 {
 
+   png_uint_32 max_palette_length;
+
    png_debug1(1, "in %s storage function", "PLTE");
 
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-   if (num_palette < 0 || num_palette > PNG_MAX_PALETTE_LENGTH)
+   max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
+      (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
+
+   if (num_palette < 0 || num_palette > (int) max_palette_length)
    {
       if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
          png_error(png_ptr, "Invalid palette length");
@@ -519,6 +531,7 @@ png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
       else
       {
          png_warning(png_ptr, "Invalid palette length");
+
          return;
       }
    }
@@ -531,7 +544,6 @@ png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
       ))
    {
       png_error(png_ptr, "Invalid palette");
-      return;
    }
 
    /* It may not actually be necessary to set png_ptr->palette here;
@@ -544,8 +556,8 @@ png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
    png_free_data(png_ptr, info_ptr, PNG_FREE_PLTE, 0);
 
    /* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
-    * of num_palette entries, in case of an invalid PNG file that has
-    * too-large sample values.
+    * of num_palette entries, in case of an invalid PNG file or incorrect
+    * call to png_set_PLTE() with too-large sample values.
     */
    png_ptr->palette = png_voidcast(png_colorp, png_calloc(png_ptr,
        PNG_MAX_PALETTE_LENGTH * (sizeof (png_color))));
@@ -655,6 +667,7 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
    if (new_iccp_name == NULL)
    {
       png_benign_error(png_ptr, "Insufficient memory to process iCCP chunk");
+
       return;
    }
 
@@ -665,9 +678,9 @@ png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
    if (new_iccp_profile == NULL)
    {
       png_free(png_ptr, new_iccp_name);
-      new_iccp_name = NULL;
       png_benign_error(png_ptr,
           "Insufficient memory to process iCCP profile");
+
       return;
    }
 
@@ -701,7 +714,7 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
 {
    int i;
 
-   png_debug1(1, "in %lx storage function", png_ptr == NULL ? "unexpected" :
+   png_debug1(1, "in %lx storage function", png_ptr == NULL ? 0xabadca11U :
       (unsigned long)png_ptr->chunk_name);
 
    if (png_ptr == NULL || info_ptr == NULL || num_text <= 0 || text_ptr == NULL)
@@ -743,6 +756,7 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
       {
          png_chunk_report(png_ptr, "too many text chunks",
             PNG_CHUNK_WRITE_ERROR);
+
          return 1;
       }
 
@@ -798,7 +812,7 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
          else
             lang_key_len = 0;
       }
-#  else /* PNG_iTXt_SUPPORTED */
+#  else /* iTXt */
       {
          png_chunk_report(png_ptr, "iTXt chunk not supported",
             PNG_CHUNK_WRITE_ERROR);
@@ -831,6 +845,7 @@ png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
       {
          png_chunk_report(png_ptr, "text chunk: out of memory",
                PNG_CHUNK_WRITE_ERROR);
+
          return 1;
       }
 
@@ -904,6 +919,7 @@ png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
        mod_time->second > 60)
    {
       png_warning(png_ptr, "Ignoring invalid time value");
+
       return;
    }
 
@@ -920,6 +936,7 @@ png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
    png_debug1(1, "in %s storage function", "tRNS");
 
    if (png_ptr == NULL || info_ptr == NULL)
+
       return;
 
    if (trans_alpha != NULL)
@@ -945,16 +962,21 @@ png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
 
    if (trans_color != NULL)
    {
-      int sample_max = (1 << info_ptr->bit_depth);
-
-      if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
-          trans_color->gray > sample_max) ||
-          (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
-          (trans_color->red > sample_max ||
-          trans_color->green > sample_max ||
-          trans_color->blue > sample_max)))
-         png_warning(png_ptr,
-            "tRNS chunk has out-of-range samples for bit_depth");
+#ifdef PNG_WARNINGS_SUPPORTED
+      if (info_ptr->bit_depth < 16)
+      {
+         int sample_max = (1 << info_ptr->bit_depth) - 1;
+
+         if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
+             trans_color->gray > sample_max) ||
+             (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+             (trans_color->red > sample_max ||
+             trans_color->green > sample_max ||
+             trans_color->blue > sample_max)))
+            png_warning(png_ptr,
+               "tRNS chunk has out-of-range samples for bit_depth");
+      }
+#endif
 
       info_ptr->trans_color = *trans_color;
 
@@ -1001,6 +1023,7 @@ png_set_sPLT(png_const_structrp png_ptr,
    {
       /* Out of memory or too many chunks */
       png_chunk_report(png_ptr, "too many sPLT chunks", PNG_CHUNK_WRITE_ERROR);
+
       return;
    }
 
@@ -1116,7 +1139,7 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
    png_unknown_chunkp np;
 
    if (png_ptr == NULL || info_ptr == NULL || num_unknowns <= 0 ||
-      unknowns == NULL)
+       unknowns == NULL)
       return;
 
    /* Check for the failure cases where support has been disabled at compile
@@ -1130,6 +1153,7 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
       if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
       {
          png_app_error(png_ptr, "no unknown chunk support on read");
+
          return;
       }
 #  endif
@@ -1138,6 +1162,7 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
       if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
       {
          png_app_error(png_ptr, "no unknown chunk support on write");
+
          return;
       }
 #  endif
@@ -1155,6 +1180,7 @@ png_set_unknown_chunks(png_const_structrp png_ptr,
    {
       png_chunk_report(png_ptr, "too many unknown chunks",
          PNG_CHUNK_WRITE_ERROR);
+
       return;
    }
 
@@ -1232,8 +1258,7 @@ png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
          check_location(png_ptr, location);
    }
 }
-#endif
-
+#endif /* STORE_UNKNOWN_CHUNKS */
 
 #ifdef PNG_MNG_FEATURES_SUPPORTED
 png_uint_32 PNGAPI
@@ -1264,6 +1289,7 @@ add_one_chunk(png_bytep list, unsigned int count, png_const_bytep add, int keep)
       if (memcmp(list, add, 4) == 0)
       {
          list[4] = (png_byte)keep;
+
          return count;
       }
    }
@@ -1291,6 +1317,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
    if (keep < 0 || keep >= PNG_HANDLE_CHUNK_LAST)
    {
       png_app_error(png_ptr, "png_set_keep_unknown_chunks: invalid keep");
+
       return;
    }
 
@@ -1340,6 +1367,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
           * which can be switched off.
           */
          png_app_error(png_ptr, "png_set_keep_unknown_chunks: no chunk list");
+
          return;
       }
 
@@ -1355,6 +1383,7 @@ png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
    if (num_chunks + old_num_chunks > UINT_MAX/5)
    {
       png_app_error(png_ptr, "png_set_keep_unknown_chunks: too many chunks");
+
       return;
    }
 
@@ -1492,23 +1521,30 @@ png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
          {
             png_warning(png_ptr,
               "Compression buffer size cannot be changed because it is in use");
+
             return;
          }
 
+#ifndef __COVERITY__
+         /* Some compilers complain that this is always false.  However, it
+          * can be true when integer overflow happens.
+          */
          if (size > ZLIB_IO_MAX)
          {
             png_warning(png_ptr,
                "Compression buffer size limited to system maximum");
             size = ZLIB_IO_MAX; /* must fit */
          }
+#endif
 
-         else if (size < 6)
+         if (size < 6)
          {
             /* Deflate will potentially go into an infinite loop on a SYNC_FLUSH
              * if this is permitted.
              */
             png_warning(png_ptr,
                "Compression buffer size cannot be reduced below 6");
+
             return;
          }
 
@@ -1537,7 +1573,7 @@ png_set_user_limits (png_structrp png_ptr, png_uint_32 user_width_max,
 {
    /* Images with dimensions larger than these limits will be
     * rejected by png_set_IHDR().  To accept any PNG datastream
-    * regardless of dimensions, set both limits to 0x7ffffffL.
+    * regardless of dimensions, set both limits to 0x7ffffff.
     */
    if (png_ptr == NULL)
       return;
@@ -1550,8 +1586,8 @@ png_set_user_limits (png_structrp png_ptr, png_uint_32 user_width_max,
 void PNGAPI
 png_set_chunk_cache_max (png_structrp png_ptr, png_uint_32 user_chunk_cache_max)
 {
-    if (png_ptr != NULL)
-       png_ptr->user_chunk_cache_max = user_chunk_cache_max;
+   if (png_ptr != NULL)
+      png_ptr->user_chunk_cache_max = user_chunk_cache_max;
 }
 
 /* This function was added to libpng 1.4.1 */
diff --git a/thirdparty/libpng/pngstruct.h b/thirdparty/libpng/pngstruct.h
index c1dd026a..c8c0e46e 100644
--- a/thirdparty/libpng/pngstruct.h
+++ b/thirdparty/libpng/pngstruct.h
@@ -1,12 +1,11 @@
 
 /* pngstruct.h - header file for PNG reference library
  *
- * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.18 [July 23, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
- * Last changed in libpng 1.6.1 [March 28, 2013]
- *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
  * and license in png.h
@@ -101,7 +100,7 @@ typedef struct png_XYZ
 #endif /* COLORSPACE */
 
 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
-/* A colorspace is all the above plus, potentially, profile information,
+/* A colorspace is all the above plus, potentially, profile information;
  * however at present libpng does not use the profile internally so it is only
  * stored in the png_info struct (if iCCP is supported.)  The rendering intent
  * is retained here and is checked.
@@ -220,16 +219,18 @@ struct png_struct_def
    png_uint_32 row_number;    /* current row in interlace pass */
    png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
    png_bytep prev_row;        /* buffer to save previous (unfiltered) row.
-                               * This is a pointer into big_prev_row
+                               * While reading this is a pointer into
+                               * big_prev_row; while writing it is separately
+                               * allocated if needed.
                                */
    png_bytep row_buf;         /* buffer to save current (unfiltered) row.
-                               * This is a pointer into big_row_buf
+                               * While reading, this is a pointer into
+                               * big_row_buf; while writing it is separately
+                               * allocated.
                                */
-#ifdef PNG_WRITE_SUPPORTED
-   png_bytep sub_row;         /* buffer to save "sub" row when filtering */
-   png_bytep up_row;          /* buffer to save "up" row when filtering */
-   png_bytep avg_row;         /* buffer to save "avg" row when filtering */
-   png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   png_bytep try_row;    /* buffer to save trial row when filtering */
+   png_bytep tst_row;    /* buffer to save best trial row when filtering */
 #endif
    png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */
 
@@ -347,17 +348,7 @@ struct png_struct_def
    png_bytep quantize_index; /* index translation for palette files */
 #endif
 
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   png_byte heuristic_method;        /* heuristic for row filter selection */
-   png_byte num_prev_filters;        /* number of weights for previous rows */
-   png_bytep prev_filters;           /* filter type(s) of previous row(s) */
-   png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
-   png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
-   png_uint_16p filter_costs;        /* relative filter calculation cost */
-   png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
-#endif
-
-   /* Options */
+/* Options */
 #ifdef PNG_SET_OPTION_SUPPORTED
    png_byte options;           /* On/off state (up to 4 options) */
 #endif
diff --git a/thirdparty/libpng/pngtrans.c b/thirdparty/libpng/pngtrans.c
index 56856b48..0c0d92d8 100644
--- a/thirdparty/libpng/pngtrans.c
+++ b/thirdparty/libpng/pngtrans.c
@@ -1,8 +1,8 @@
 
 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.18 [July 23, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -30,7 +30,7 @@ png_set_bgr(png_structrp png_ptr)
 #endif
 
 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
-/* Turn on 16 bit byte swapping */
+/* Turn on 16-bit byte swapping */
 void PNGAPI
 png_set_swap(png_structrp png_ptr)
 {
@@ -313,7 +313,7 @@ png_do_invert(png_row_infop row_info, png_bytep row)
 
 #ifdef PNG_16BIT_SUPPORTED
 #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
-/* Swaps byte order on 16 bit depth images */
+/* Swaps byte order on 16-bit depth images */
 void /* PRIVATE */
 png_do_swap(png_row_infop row_info, png_bytep row)
 {
@@ -704,7 +704,7 @@ png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
              */
             for (; rp > png_ptr->row_buf; rp--)
             {
-              if (*rp >> padding != 0)
+              if ((*rp >> padding) != 0)
                  png_ptr->num_palette_max = 1;
               padding = 0;
             }
diff --git a/thirdparty/libpng/pngwio.c b/thirdparty/libpng/pngwio.c
index 0a40948a..db76e6b8 100644
--- a/thirdparty/libpng/pngwio.c
+++ b/thirdparty/libpng/pngwio.c
@@ -26,7 +26,7 @@
  * writes to a file pointer.  Note that this routine sometimes gets called
  * with very small lengths, so you should implement some kind of simple
  * buffering if you are using unbuffered writes.  This should never be asked
- * to write more than 64K on a 16 bit machine.
+ * to write more than 64K on a 16-bit machine.
  */
 
 void /* PRIVATE */
diff --git a/thirdparty/libpng/pngwrite.c b/thirdparty/libpng/pngwrite.c
index 94548877..0d4ee9f7 100644
--- a/thirdparty/libpng/pngwrite.c
+++ b/thirdparty/libpng/pngwrite.c
@@ -1,8 +1,8 @@
 
 /* pngwrite.c - general routines to write a PNG file
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.19 [November 12, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -90,43 +90,44 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
 
    if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
    {
-   /* Write PNG signature */
-   png_write_sig(png_ptr);
+      /* Write PNG signature */
+      png_write_sig(png_ptr);
 
 #ifdef PNG_MNG_FEATURES_SUPPORTED
-   if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
-       png_ptr->mng_features_permitted != 0)
-   {
-      png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
-      png_ptr->mng_features_permitted = 0;
-   }
+      if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
+          png_ptr->mng_features_permitted != 0)
+      {
+         png_warning(png_ptr,
+             "MNG features are not allowed in a PNG datastream");
+         png_ptr->mng_features_permitted = 0;
+      }
 #endif
 
-   /* Write IHDR information. */
-   png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
-       info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
-       info_ptr->filter_type,
+      /* Write IHDR information. */
+      png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
+          info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
+          info_ptr->filter_type,
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
-       info_ptr->interlace_type
+          info_ptr->interlace_type
 #else
-       0
+          0
 #endif
-      );
+         );
 
-   /* The rest of these check to see if the valid field has the appropriate
-    * flag set, and if it does, writes the chunk.
-    *
-    * 1.6.0: COLORSPACE support controls the writing of these chunks too, and
-    * the chunks will be written if the WRITE routine is there and information
-    * is available in the COLORSPACE.  (See png_colorspace_sync_info in png.c
-    * for where the valid flags get set.)
-    *
-    * Under certain circumstances the colorspace can be invalidated without
-    * syncing the info_struct 'valid' flags; this happens if libpng detects and
-    * error and calls png_error while the color space is being set, yet the
-    * application continues writing the PNG.  So check the 'invalid' flag here
-    * too.
-    */
+      /* The rest of these check to see if the valid field has the appropriate
+       * flag set, and if it does, writes the chunk.
+       *
+       * 1.6.0: COLORSPACE support controls the writing of these chunks too, and
+       * the chunks will be written if the WRITE routine is there and
+       * information * is available in the COLORSPACE. (See
+       * png_colorspace_sync_info in png.c for where the valid flags get set.)
+       *
+       * Under certain circumstances the colorspace can be invalidated without
+       * syncing the info_struct 'valid' flags; this happens if libpng detects
+       * an error and calls png_error while the color space is being set, yet
+       * the application continues writing the PNG.  So check the 'invalid'
+       * flag here too.
+       */
 #ifdef PNG_GAMMA_SUPPORTED
 #  ifdef PNG_WRITE_gAMA_SUPPORTED
       if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
@@ -137,50 +138,50 @@ png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
 #endif
 
 #ifdef PNG_COLORSPACE_SUPPORTED
-   /* Write only one of sRGB or an ICC profile.  If a profile was supplied
-    * and it matches one of the known sRGB ones issue a warning.
-    */
+      /* Write only one of sRGB or an ICC profile.  If a profile was supplied
+       * and it matches one of the known sRGB ones issue a warning.
+       */
 #  ifdef PNG_WRITE_iCCP_SUPPORTED
-      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-          (info_ptr->valid & PNG_INFO_iCCP) != 0)
-      {
-#        ifdef PNG_WRITE_sRGB_SUPPORTED
-            if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
-               png_app_warning(png_ptr,
-                  "profile matches sRGB but writing iCCP instead");
-#        endif
-
-         png_write_iCCP(png_ptr, info_ptr->iccp_name,
-            info_ptr->iccp_profile);
-      }
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+             (info_ptr->valid & PNG_INFO_iCCP) != 0)
+         {
+#    ifdef PNG_WRITE_sRGB_SUPPORTED
+               if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
+                  png_app_warning(png_ptr,
+                     "profile matches sRGB but writing iCCP instead");
+#     endif
+
+            png_write_iCCP(png_ptr, info_ptr->iccp_name,
+               info_ptr->iccp_profile);
+         }
 #     ifdef PNG_WRITE_sRGB_SUPPORTED
          else
 #     endif
 #  endif
 
 #  ifdef PNG_WRITE_sRGB_SUPPORTED
-      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-          (info_ptr->valid & PNG_INFO_sRGB) != 0)
-         png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+             (info_ptr->valid & PNG_INFO_sRGB) != 0)
+            png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
 #  endif /* WRITE_sRGB */
 #endif /* COLORSPACE */
 
 #ifdef PNG_WRITE_sBIT_SUPPORTED
-   if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
-      png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
+         if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+            png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
 #endif
 
 #ifdef PNG_COLORSPACE_SUPPORTED
 #  ifdef PNG_WRITE_cHRM_SUPPORTED
-      if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
-         (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
-         (info_ptr->valid & PNG_INFO_cHRM) != 0)
-         png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
+         if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+             (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
+             (info_ptr->valid & PNG_INFO_cHRM) != 0)
+            png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
 #  endif
 #endif
 
 #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
-      write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
+         write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
 #endif
 
       png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
@@ -205,7 +206,7 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
       png_write_PLTE(png_ptr, info_ptr->palette,
           (png_uint_32)info_ptr->num_palette);
 
-   else if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) !=0)
+   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       png_error(png_ptr, "Valid palette required for paletted images");
 
 #ifdef PNG_WRITE_tRNS_SUPPORTED
@@ -216,8 +217,13 @@ png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
       if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
           info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {
-         int j;
-         for (j = 0; j<(int)info_ptr->num_trans; j++)
+         int j, jend;
+
+         jend = info_ptr->num_trans;
+         if (jend > PNG_MAX_PALETTE_LENGTH)
+            jend = PNG_MAX_PALETTE_LENGTH;
+
+         for (j = 0; j<jend; ++j)
             info_ptr->trans_alpha[j] =
                (png_byte)(255 - info_ptr->trans_alpha[j]);
       }
@@ -538,7 +544,7 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
       /* App warnings are warnings in release (or release candidate) builds but
        * are errors during development.
        */
-#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+#if PNG_RELEASE_BUILD
       png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
 #endif
 
@@ -638,8 +644,8 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
 
          for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
          {
-            *(rp)     = (png_byte)((*rp       - *(rp + 1)) & 0xff);
-            *(rp + 2) = (png_byte)((*(rp + 2) - *(rp + 1)) & 0xff);
+            *(rp)     = (png_byte)(*rp       - *(rp + 1));
+            *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
          }
       }
 
@@ -665,10 +671,10 @@ png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
             png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
             png_uint_32 red  = (png_uint_32)((s0 - s1) & 0xffffL);
             png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
-            *(rp    ) = (png_byte)((red >> 8) & 0xff);
-            *(rp + 1) = (png_byte)(red & 0xff);
-            *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
-            *(rp + 5) = (png_byte)(blue & 0xff);
+            *(rp    ) = (png_byte)(red >> 8);
+            *(rp + 1) = (png_byte)red;
+            *(rp + 4) = (png_byte)(blue >> 8);
+            *(rp + 5) = (png_byte)blue;
          }
       }
 #endif /* WRITE_16BIT */
@@ -849,7 +855,7 @@ png_write_row(png_structrp png_ptr, png_const_bytep row)
     * which is also the output depth.
     */
    if (row_info.pixel_depth != png_ptr->pixel_depth ||
-      row_info.pixel_depth != png_ptr->transformed_pixel_depth)
+       row_info.pixel_depth != png_ptr->transformed_pixel_depth)
       png_error(png_ptr, "internal write transform logic error");
 
 #ifdef PNG_MNG_FEATURES_SUPPORTED
@@ -917,10 +923,6 @@ png_write_flush(png_structrp png_ptr)
 }
 #endif /* WRITE_FLUSH */
 
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-static void png_reset_filter_heuristics(png_structrp png_ptr);/* forward decl */
-#endif
-
 /* Free any memory used in png_ptr struct without freeing the struct itself. */
 static void
 png_write_destroy(png_structrp png_ptr)
@@ -937,24 +939,11 @@ png_write_destroy(png_structrp png_ptr)
    png_ptr->row_buf = NULL;
 #ifdef PNG_WRITE_FILTER_SUPPORTED
    png_free(png_ptr, png_ptr->prev_row);
-   png_free(png_ptr, png_ptr->sub_row);
-   png_free(png_ptr, png_ptr->up_row);
-   png_free(png_ptr, png_ptr->avg_row);
-   png_free(png_ptr, png_ptr->paeth_row);
+   png_free(png_ptr, png_ptr->try_row);
+   png_free(png_ptr, png_ptr->tst_row);
    png_ptr->prev_row = NULL;
-   png_ptr->sub_row = NULL;
-   png_ptr->up_row = NULL;
-   png_ptr->avg_row = NULL;
-   png_ptr->paeth_row = NULL;
-#endif
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   /* Use this to save a little code space, it doesn't free the filter_costs */
-   png_reset_filter_heuristics(png_ptr);
-   png_free(png_ptr, png_ptr->filter_costs);
-   png_free(png_ptr, png_ptr->inv_filter_costs);
-   png_ptr->filter_costs = NULL;
-   png_ptr->inv_filter_costs = NULL;
+   png_ptr->try_row = NULL;
+   png_ptr->tst_row = NULL;
 #endif
 
 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
@@ -1044,211 +1033,85 @@ png_set_filter(png_structrp png_ptr, int method, int filters)
 #endif /* WRITE_FILTER */
       }
 
+#ifdef PNG_WRITE_FILTER_SUPPORTED
       /* If we have allocated the row_buf, this means we have already started
        * with the image and we should have allocated all of the filter buffers
        * that have been selected.  If prev_row isn't already allocated, then
        * it is too late to start using the filters that need it, since we
        * will be missing the data in the previous row.  If an application
        * wants to start and stop using particular filters during compression,
-       * it should start out with all of the filters, and then add and
-       * remove them after the start of compression.
+       * it should start out with all of the filters, and then remove them
+       * or add them back after the start of compression.
+       *
+       * NOTE: this is a nasty constraint on the code, because it means that the
+       * prev_row buffer must be maintained even if there are currently no
+       * 'prev_row' requiring filters active.
        */
       if (png_ptr->row_buf != NULL)
       {
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-         if ((png_ptr->do_filter & PNG_FILTER_SUB) != 0 &&
-             png_ptr->sub_row == NULL)
-         {
-            png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
-                (png_ptr->rowbytes + 1));
-            png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
-         }
+         int num_filters;
+         png_alloc_size_t buf_size;
 
-         if ((png_ptr->do_filter & PNG_FILTER_UP) != 0 &&
-              png_ptr->up_row == NULL)
-         {
-            if (png_ptr->prev_row == NULL)
-            {
-               png_warning(png_ptr, "Can't add Up filter after starting");
-               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
-                   ~PNG_FILTER_UP);
-            }
-
-            else
-            {
-               png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
-                   (png_ptr->rowbytes + 1));
-               png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
-            }
-         }
-
-         if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0 &&
-              png_ptr->avg_row == NULL)
-         {
-            if (png_ptr->prev_row == NULL)
-            {
-               png_warning(png_ptr, "Can't add Average filter after starting");
-               png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
-                   ~PNG_FILTER_AVG);
-            }
+         /* Repeat the checks in png_write_start_row; 1 pixel high or wide
+          * images cannot benefit from certain filters.  If this isn't done here
+          * the check below will fire on 1 pixel high images.
+          */
+         if (png_ptr->height == 1)
+            filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
 
-            else
-            {
-               png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
-                   (png_ptr->rowbytes + 1));
-               png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
-            }
-         }
+         if (png_ptr->width == 1)
+            filters &= ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
 
-         if ((png_ptr->do_filter & PNG_FILTER_PAETH) != 0 &&
-             png_ptr->paeth_row == NULL)
+         if ((filters & (PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH)) != 0
+            && png_ptr->prev_row == NULL)
          {
-            if (png_ptr->prev_row == NULL)
-            {
-               png_warning(png_ptr, "Can't add Paeth filter after starting");
-               png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
-            }
-
-            else
-            {
-               png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
-                   (png_ptr->rowbytes + 1));
-               png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
-            }
+            /* This is the error case, however it is benign - the previous row
+             * is not available so the filter can't be used.  Just warn here.
+             */
+            png_app_warning(png_ptr,
+               "png_set_filter: UP/AVG/PAETH cannot be added after start");
+            filters &= ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
          }
 
-         if (png_ptr->do_filter == PNG_NO_FILTERS)
-#endif /* WRITE_FILTER */
-            png_ptr->do_filter = PNG_FILTER_NONE;
-      }
-   }
-   else
-      png_error(png_ptr, "Unknown custom filter method");
-}
+         num_filters = 0;
 
-/* This allows us to influence the way in which libpng chooses the "best"
- * filter for the current scanline.  While the "minimum-sum-of-absolute-
- * differences metric is relatively fast and effective, there is some
- * question as to whether it can be improved upon by trying to keep the
- * filtered data going to zlib more consistent, hopefully resulting in
- * better compression.
- */
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED      /* GRR 970116 */
-/* Convenience reset API. */
-static void
-png_reset_filter_heuristics(png_structrp png_ptr)
-{
-   /* Clear out any old values in the 'weights' - this must be done because if
-    * the app calls set_filter_heuristics multiple times with different
-    * 'num_weights' values we would otherwise potentially have wrong sized
-    * arrays.
-    */
-   png_ptr->num_prev_filters = 0;
-   png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;
-   if (png_ptr->prev_filters != NULL)
-   {
-      png_bytep old = png_ptr->prev_filters;
-      png_ptr->prev_filters = NULL;
-      png_free(png_ptr, old);
-   }
-   if (png_ptr->filter_weights != NULL)
-   {
-      png_uint_16p old = png_ptr->filter_weights;
-      png_ptr->filter_weights = NULL;
-      png_free(png_ptr, old);
-   }
+         if (filters & PNG_FILTER_SUB)
+            num_filters++;
 
-   if (png_ptr->inv_filter_weights != NULL)
-   {
-      png_uint_16p old = png_ptr->inv_filter_weights;
-      png_ptr->inv_filter_weights = NULL;
-      png_free(png_ptr, old);
-   }
+         if (filters & PNG_FILTER_UP)
+            num_filters++;
 
-   /* Leave the filter_costs - this array is fixed size. */
-}
+         if (filters & PNG_FILTER_AVG)
+            num_filters++;
 
-static int
-png_init_filter_heuristics(png_structrp png_ptr, int heuristic_method,
-   int num_weights)
-{
-   if (png_ptr == NULL)
-      return 0;
+         if (filters & PNG_FILTER_PAETH)
+            num_filters++;
 
-   /* Clear out the arrays */
-   png_reset_filter_heuristics(png_ptr);
-
-   /* Check arguments; the 'reset' function makes the correct settings for the
-    * unweighted case, but we must handle the weight case by initializing the
-    * arrays for the caller.
-    */
-   if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-   {
-      int i;
-
-      if (num_weights > 0)
-      {
-         png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr,
-             (png_uint_32)((sizeof (png_byte)) * num_weights));
-
-         /* To make sure that the weighting starts out fairly */
-         for (i = 0; i < num_weights; i++)
-         {
-            png_ptr->prev_filters[i] = 255;
-         }
-
-         png_ptr->filter_weights = (png_uint_16p)png_malloc(png_ptr,
-             (png_uint_32)((sizeof (png_uint_16)) * num_weights));
+         /* Allocate needed row buffers if they have not already been
+          * allocated.
+          */
+         buf_size = PNG_ROWBYTES(png_ptr->usr_channels * png_ptr->usr_bit_depth,
+             png_ptr->width) + 1;
 
-         png_ptr->inv_filter_weights = (png_uint_16p)png_malloc(png_ptr,
-             (png_uint_32)((sizeof (png_uint_16)) * num_weights));
+         if (png_ptr->try_row == NULL)
+            png_ptr->try_row = png_voidcast(png_bytep,
+               png_malloc(png_ptr, buf_size));
 
-         for (i = 0; i < num_weights; i++)
+         if (num_filters > 1)
          {
-            png_ptr->inv_filter_weights[i] =
-            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
+            if (png_ptr->tst_row == NULL)
+               png_ptr->tst_row = png_voidcast(png_bytep,
+                  png_malloc(png_ptr, buf_size));
          }
-
-         /* Safe to set this now */
-         png_ptr->num_prev_filters = (png_byte)num_weights;
-      }
-
-      /* If, in the future, there are other filter methods, this would
-       * need to be based on png_ptr->filter.
-       */
-      if (png_ptr->filter_costs == NULL)
-      {
-         png_ptr->filter_costs = (png_uint_16p)png_malloc(png_ptr,
-             (png_uint_32)((sizeof (png_uint_16)) * PNG_FILTER_VALUE_LAST));
-
-         png_ptr->inv_filter_costs = (png_uint_16p)png_malloc(png_ptr,
-             (png_uint_32)((sizeof (png_uint_16)) * PNG_FILTER_VALUE_LAST));
       }
-
-      for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
-      {
-         png_ptr->inv_filter_costs[i] =
-         png_ptr->filter_costs[i] = PNG_COST_FACTOR;
-      }
-
-      /* All the arrays are inited, safe to set this: */
-      png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_WEIGHTED;
-
-      /* Return the 'ok' code. */
-      return 1;
-   }
-   else if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT ||
-      heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED)
-   {
-      return 1;
+      png_ptr->do_filter = (png_byte)filters;
+#endif
    }
    else
-   {
-      png_warning(png_ptr, "Unknown filter heuristic method");
-      return 0;
-   }
+      png_error(png_ptr, "Unknown custom filter method");
 }
 
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* DEPRECATED */
 /* Provide floating and fixed point APIs */
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 void PNGAPI
@@ -1256,52 +1119,11 @@ png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
     int num_weights, png_const_doublep filter_weights,
     png_const_doublep filter_costs)
 {
-   png_debug(1, "in png_set_filter_heuristics");
-
-   /* The internal API allocates all the arrays and ensures that the elements of
-    * those arrays are set to the default value.
-    */
-   if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
-      return;
-
-   /* If using the weighted method copy in the weights. */
-   if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-   {
-      int i;
-      for (i = 0; i < num_weights; i++)
-      {
-         if (filter_weights[i] <= 0.0)
-         {
-            png_ptr->inv_filter_weights[i] =
-            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
-         }
-
-         else
-         {
-            png_ptr->inv_filter_weights[i] =
-                (png_uint_16)(PNG_WEIGHT_FACTOR*filter_weights[i]+.5);
-
-            png_ptr->filter_weights[i] =
-                (png_uint_16)(PNG_WEIGHT_FACTOR/filter_weights[i]+.5);
-         }
-      }
-
-      /* Here is where we set the relative costs of the different filters.  We
-       * should take the desired compression level into account when setting
-       * the costs, so that Paeth, for instance, has a high relative cost at low
-       * compression levels, while it has a lower relative cost at higher
-       * compression settings.  The filter types are in order of increasing
-       * relative cost, so it would be possible to do this with an algorithm.
-       */
-      for (i = 0; i < PNG_FILTER_VALUE_LAST; i++) if (filter_costs[i] >= 1.0)
-      {
-         png_ptr->inv_filter_costs[i] =
-             (png_uint_16)(PNG_COST_FACTOR / filter_costs[i] + .5);
-
-         png_ptr->filter_costs[i] =
-             (png_uint_16)(PNG_COST_FACTOR * filter_costs[i] + .5);
-      }
-   }
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(heuristic_method)
+   PNG_UNUSED(num_weights)
+   PNG_UNUSED(filter_weights)
+   PNG_UNUSED(filter_costs)
 }
 #endif /* FLOATING_POINT */
 
@@ -1311,67 +1133,16 @@ png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
     int num_weights, png_const_fixed_point_p filter_weights,
     png_const_fixed_point_p filter_costs)
 {
-   png_debug(1, "in png_set_filter_heuristics_fixed");
-
-   /* The internal API allocates all the arrays and ensures that the elements of
-    * those arrays are set to the default value.
-    */
-   if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
-      return;
-
-   /* If using the weighted method copy in the weights. */
-   if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-   {
-      int i;
-      for (i = 0; i < num_weights; i++)
-      {
-         if (filter_weights[i] <= 0)
-         {
-            png_ptr->inv_filter_weights[i] =
-            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
-         }
-
-         else
-         {
-            png_ptr->inv_filter_weights[i] = (png_uint_16)
-               ((PNG_WEIGHT_FACTOR*filter_weights[i]+PNG_FP_HALF)/PNG_FP_1);
-
-            png_ptr->filter_weights[i] = (png_uint_16)((PNG_WEIGHT_FACTOR*
-               PNG_FP_1+(filter_weights[i]/2))/filter_weights[i]);
-         }
-      }
-
-      /* Here is where we set the relative costs of the different filters.  We
-       * should take the desired compression level into account when setting
-       * the costs, so that Paeth, for instance, has a high relative cost at low
-       * compression levels, while it has a lower relative cost at higher
-       * compression settings.  The filter types are in order of increasing
-       * relative cost, so it would be possible to do this with an algorithm.
-       */
-      for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
-         if (filter_costs[i] >= PNG_FP_1)
-      {
-         png_uint_32 tmp;
-
-         /* Use a 32 bit unsigned temporary here because otherwise the
-          * intermediate value will be a 32 bit *signed* integer (ANSI rules)
-          * and this will get the wrong answer on division.
-          */
-         tmp = PNG_COST_FACTOR*PNG_FP_1 + (filter_costs[i]/2);
-         tmp /= filter_costs[i];
-
-         png_ptr->inv_filter_costs[i] = (png_uint_16)tmp;
-
-         tmp = PNG_COST_FACTOR * filter_costs[i] + PNG_FP_HALF;
-         tmp /= PNG_FP_1;
-
-         png_ptr->filter_costs[i] = (png_uint_16)tmp;
-      }
-   }
+   PNG_UNUSED(png_ptr)
+   PNG_UNUSED(heuristic_method)
+   PNG_UNUSED(num_weights)
+   PNG_UNUSED(filter_weights)
+   PNG_UNUSED(filter_costs)
 }
 #endif /* FIXED_POINT */
 #endif /* WRITE_WEIGHTED_FILTER */
 
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
 void PNGAPI
 png_set_compression_level(png_structrp png_ptr, int level)
 {
@@ -1417,8 +1188,8 @@ png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
    if (png_ptr == NULL)
       return;
 
-   /* Prior to 1.6.0 this would warn but then set the window_bits value, this
-    * meant that negative window bits values could be selected which would cause
+   /* Prior to 1.6.0 this would warn but then set the window_bits value. This
+    * meant that negative window bits values could be selected that would cause
     * libpng to write a non-standard PNG file with raw deflate or gzip
     * compressed IDAT or ancillary chunks.  Such files can be read and there is
     * no warning on read, so this seems like a very bad idea.
@@ -1454,6 +1225,7 @@ png_set_compression_method(png_structrp png_ptr, int method)
 
    png_ptr->zlib_method = method;
 }
+#endif /* WRITE_CUSTOMIZE_COMPRESSION */
 
 /* The following were added to libpng-1.5.4 */
 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
@@ -1614,14 +1386,14 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
     * alpha channel.
     */
    if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
-      PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
+       PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
    {
 #ifdef PNG_WRITE_FILLER_SUPPORTED
       if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
       {
          if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
             png_app_error(png_ptr,
-               "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
+                "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
 
          /* Continue if ignored - this is the pre-1.6.10 behavior */
          png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
@@ -1650,7 +1422,7 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
       png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
 #endif
 
-   /* Swap bits of 1, 2, 4 bit packed pixel formats */
+   /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
    if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
 #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
       png_set_packswap(png_ptr);
@@ -1680,13 +1452,13 @@ png_write_png(png_structrp png_ptr, png_inforp info_ptr,
 
 
 #ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
-#ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */
+# ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */
 /* Initialize the write structure - general purpose utility. */
 static int
 png_image_write_init(png_imagep image)
 {
    png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
-          png_safe_error, png_safe_warning);
+       png_safe_error, png_safe_warning);
 
    if (png_ptr != NULL)
    {
@@ -1695,7 +1467,7 @@ png_image_write_init(png_imagep image)
       if (info_ptr != NULL)
       {
          png_controlp control = png_voidcast(png_controlp,
-            png_malloc_warn(png_ptr, (sizeof *control)));
+             png_malloc_warn(png_ptr, (sizeof *control)));
 
          if (control != NULL)
          {
@@ -1742,12 +1514,12 @@ static int
 png_write_image_16bit(png_voidp argument)
 {
    png_image_write_control *display = png_voidcast(png_image_write_control*,
-      argument);
+       argument);
    png_imagep image = display->image;
    png_structrp png_ptr = image->opaque->png_ptr;
 
    png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
-      display->first_row);
+       display->first_row);
    png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
    png_uint_16p row_end;
    const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
@@ -1756,17 +1528,18 @@ png_write_image_16bit(png_voidp argument)
 
    if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
    {
-#     ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-         if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
-         {
-            aindex = -1;
-            ++input_row; /* To point to the first component */
-            ++output_row;
-         }
-
+#   ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+      if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+      {
+         aindex = -1;
+         ++input_row; /* To point to the first component */
+         ++output_row;
+      }
          else
-#     endif
+            aindex = channels;
+#     else
          aindex = channels;
+#     endif
    }
 
    else
@@ -1848,7 +1621,7 @@ png_write_image_16bit(png_voidp argument)
  * calculation can be done to 15 bits of accuracy; however, the output needs to
  * be scaled in the range 0..255*65535, so include that scaling here.
  */
-#define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+(alpha>>1))/alpha)
+#   define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+(alpha>>1))/alpha)
 
 static png_byte
 png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
@@ -1899,12 +1672,12 @@ static int
 png_write_image_8bit(png_voidp argument)
 {
    png_image_write_control *display = png_voidcast(png_image_write_control*,
-      argument);
+       argument);
    png_imagep image = display->image;
    png_structrp png_ptr = image->opaque->png_ptr;
 
    png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
-      display->first_row);
+       display->first_row);
    png_bytep output_row = png_voidcast(png_bytep, display->local_row);
    png_uint_32 y = image->height;
    const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
@@ -1914,17 +1687,17 @@ png_write_image_8bit(png_voidp argument)
       png_bytep row_end;
       int aindex;
 
-#     ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
-         if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
-         {
-            aindex = -1;
-            ++input_row; /* To point to the first component */
-            ++output_row;
-         }
+#   ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+      if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+      {
+         aindex = -1;
+         ++input_row; /* To point to the first component */
+         ++output_row;
+      }
 
-         else
-#     endif
-         aindex = channels;
+      else
+#   endif
+      aindex = channels;
 
       /* Use row_end in place of a loop counter: */
       row_end = output_row + image->width * (channels+1);
@@ -1958,7 +1731,7 @@ png_write_image_8bit(png_voidp argument)
          } /* while out_ptr < row_end */
 
          png_write_row(png_ptr, png_voidcast(png_const_bytep,
-            display->local_row));
+             display->local_row));
          input_row += display->row_bytes/(sizeof (png_uint_16));
       } /* while y */
    }
@@ -1997,25 +1770,25 @@ png_image_set_PLTE(png_image_write_control *display)
    const png_imagep image = display->image;
    const void *cmap = display->colormap;
    const int entries = image->colormap_entries > 256 ? 256 :
-      (int)image->colormap_entries;
+       (int)image->colormap_entries;
 
    /* NOTE: the caller must check for cmap != NULL and entries != 0 */
    const png_uint_32 format = image->format;
    const int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
 
-#  if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
+#   if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
       defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
       const int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
-         (format & PNG_FORMAT_FLAG_ALPHA) != 0;
-#  else
+          (format & PNG_FORMAT_FLAG_ALPHA) != 0;
+#   else
 #     define afirst 0
-#  endif
+#   endif
 
-#  ifdef PNG_FORMAT_BGR_SUPPORTED
+#   ifdef PNG_FORMAT_BGR_SUPPORTED
       const int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
-#  else
+#   else
 #     define bgr 0
-#  endif
+#   endif
 
    int i, num_trans;
    png_color palette[256];
@@ -2040,11 +1813,11 @@ png_image_set_PLTE(png_image_write_control *display)
             if (channels >= 3) /* RGB */
             {
                palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
-                  entry[(2 ^ bgr)]);
+                   entry[(2 ^ bgr)]);
                palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
-                  entry[1]);
+                   entry[1]);
                palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
-                  entry[bgr]);
+                   entry[bgr]);
             }
 
             else /* Gray */
@@ -2120,12 +1893,12 @@ png_image_set_PLTE(png_image_write_control *display)
       }
    }
 
-#  ifdef afirst
+#   ifdef afirst
 #     undef afirst
-#  endif
-#  ifdef bgr
+#   endif
+#   ifdef bgr
 #     undef bgr
-#  endif
+#   endif
 
    png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
       entries);
@@ -2153,10 +1926,10 @@ png_image_write_main(png_voidp argument)
    int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
    int write_16bit = linear && !colormap && (display->convert_to_8bit == 0);
 
-#  ifdef PNG_BENIGN_ERRORS_SUPPORTED
+#   ifdef PNG_BENIGN_ERRORS_SUPPORTED
       /* Make sure we error out on any bad situation */
       png_set_benign_errors(png_ptr, 0/*error*/);
-#  endif
+#   endif
 
    /* Default the 'row_stride' parameter if required. */
    if (display->row_stride == 0)
@@ -2225,7 +1998,7 @@ png_image_write_main(png_voidp argument)
    /* Now set up the data transformations (*after* the header is written),
     * remove the handled transformations from the 'format' flags for checking.
     *
-    * First check for a little endian system if writing 16 bit files.
+    * First check for a little endian system if writing 16-bit files.
     */
    if (write_16bit != 0)
    {
@@ -2235,23 +2008,23 @@ png_image_write_main(png_voidp argument)
          png_set_swap(png_ptr);
    }
 
-#  ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
+#   ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
       if ((format & PNG_FORMAT_FLAG_BGR) != 0)
       {
          if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
             png_set_bgr(png_ptr);
          format &= ~PNG_FORMAT_FLAG_BGR;
       }
-#  endif
+#   endif
 
-#  ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+#   ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
       if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
       {
          if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
             png_set_swap_alpha(png_ptr);
          format &= ~PNG_FORMAT_FLAG_AFIRST;
       }
-#  endif
+#   endif
 
    /* If there are 16 or fewer color-map entries we wrote a lower bit depth
     * above, but the application data is still byte packed.
@@ -2287,7 +2060,9 @@ png_image_write_main(png_voidp argument)
        * it about 50 times.  The speed-up in pngstest was about 10-20% of the
        * total (user) time on a heavily loaded system.
        */
+#   ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
       png_set_compression_level(png_ptr, 3);
+#   endif
    }
 
    /* Check for the cases that currently require a pre-transform on the row
@@ -2450,6 +2225,6 @@ png_image_write_to_file(png_imagep image, const char *file_name,
    else
       return 0;
 }
-#endif /* STDIO */
+# endif /* STDIO */
 #endif /* SIMPLIFIED_WRITE */
 #endif /* WRITE */
diff --git a/thirdparty/libpng/pngwtran.c b/thirdparty/libpng/pngwtran.c
index 09562a78..5dc94915 100644
--- a/thirdparty/libpng/pngwtran.c
+++ b/thirdparty/libpng/pngwtran.c
@@ -1,8 +1,8 @@
 
 /* pngwtran.c - transforms the data in a row for PNG writers
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.18 [July 23, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -71,7 +71,8 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
          case 2:
          {
             png_bytep sp, dp;
-            int shift, v;
+            unsigned int shift;
+            int v;
             png_uint_32 i;
             png_uint_32 row_width = row_info->width;
 
@@ -110,7 +111,8 @@ png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
          case 4:
          {
             png_bytep sp, dp;
-            int shift, v;
+            unsigned int shift;
+            int v;
             png_uint_32 i;
             png_uint_32 row_width = row_info->width;
 
@@ -422,7 +424,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
                *(dp++) = *(sp++);
                */
                sp+=3; dp = sp;
-               *(dp++) = (png_byte)(255 - *(sp++));
+               *dp = (png_byte)(255 - *(sp++));
             }
          }
 
@@ -446,7 +448,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
                */
                sp+=6; dp = sp;
                *(dp++) = (png_byte)(255 - *(sp++));
-               *(dp++) = (png_byte)(255 - *(sp++));
+               *dp     = (png_byte)(255 - *(sp++));
             }
          }
 #endif /* WRITE_16BIT */
@@ -484,7 +486,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
                */
                sp+=2; dp = sp;
                *(dp++) = (png_byte)(255 - *(sp++));
-               *(dp++) = (png_byte)(255 - *(sp++));
+               *dp     = (png_byte)(255 - *(sp++));
             }
          }
 #endif /* WRITE_16BIT */
diff --git a/thirdparty/libpng/pngwutil.c b/thirdparty/libpng/pngwutil.c
index 10c1edff..adc4729c 100644
--- a/thirdparty/libpng/pngwutil.c
+++ b/thirdparty/libpng/pngwutil.c
@@ -1,8 +1,8 @@
 
 /* pngwutil.c - utilities to write a PNG file
  *
- * Last changed in libpng 1.6.15 [November 20, 2014]
- * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.19 [November 12, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
@@ -23,10 +23,10 @@
 void PNGAPI
 png_save_uint_32(png_bytep buf, png_uint_32 i)
 {
-   buf[0] = (png_byte)((i >> 24) & 0xff);
-   buf[1] = (png_byte)((i >> 16) & 0xff);
-   buf[2] = (png_byte)((i >> 8) & 0xff);
-   buf[3] = (png_byte)(i & 0xff);
+   buf[0] = (png_byte)(i >> 24);
+   buf[1] = (png_byte)(i >> 16);
+   buf[2] = (png_byte)(i >> 8);
+   buf[3] = (png_byte)(i     );
 }
 
 /* Place a 16-bit number into a buffer in PNG byte order.
@@ -36,8 +36,8 @@ png_save_uint_32(png_bytep buf, png_uint_32 i)
 void PNGAPI
 png_save_uint_16(png_bytep buf, unsigned int i)
 {
-   buf[0] = (png_byte)((i >> 8) & 0xff);
-   buf[1] = (png_byte)(i & 0xff);
+   buf[0] = (png_byte)(i >> 8);
+   buf[1] = (png_byte)(i     );
 }
 #endif
 
@@ -179,7 +179,7 @@ png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
    if (png_ptr == NULL)
       return;
 
-   /* On 64 bit architectures 'length' may not fit in a png_uint_32. */
+   /* On 64-bit architectures 'length' may not fit in a png_uint_32. */
    if (length > PNG_UINT_31_MAX)
       png_error(png_ptr, "length exceeds PNG maximum");
 
@@ -308,7 +308,7 @@ png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
        */
       (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
 #endif
-#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+#if PNG_RELEASE_BUILD
          png_warning(png_ptr, msg);
 
          /* Attempt sane error recovery */
@@ -695,7 +695,7 @@ png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
 
    while (*key && key_len < 79)
    {
-      png_byte ch = (png_byte)(0xff & *key++);
+      png_byte ch = (png_byte)*key++;
 
       if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
          *new_key++ = ch, ++key_len, space = 0;
@@ -871,7 +871,7 @@ png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
    interlace_type=PNG_INTERLACE_NONE;
 #endif
 
-   /* Save the relevent information */
+   /* Save the relevant information */
    png_ptr->bit_depth = (png_byte)bit_depth;
    png_ptr->color_type = (png_byte)color_type;
    png_ptr->interlaced = (png_byte)interlace_type;
@@ -922,17 +922,20 @@ void /* PRIVATE */
 png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
     png_uint_32 num_pal)
 {
-   png_uint_32 i;
+   png_uint_32 max_palette_length, i;
    png_const_colorp pal_ptr;
    png_byte buf[3];
 
    png_debug(1, "in png_write_PLTE");
 
+   max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
+      (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
+
    if ((
 #ifdef PNG_MNG_FEATURES_SUPPORTED
        (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
 #endif
-       num_pal == 0) || num_pal > 256)
+       num_pal == 0) || num_pal > max_palette_length)
    {
       if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {
@@ -1444,7 +1447,7 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
 
    else if (color_type == PNG_COLOR_TYPE_GRAY)
    {
-      /* One 16 bit value */
+      /* One 16-bit value */
       if (tran->gray >= (1 << png_ptr->bit_depth))
       {
          png_app_warning(png_ptr,
@@ -1459,7 +1462,7 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
 
    else if (color_type == PNG_COLOR_TYPE_RGB)
    {
-      /* Three 16 bit values */
+      /* Three 16-bit values */
       png_save_uint_16(buf, tran->red);
       png_save_uint_16(buf + 2, tran->green);
       png_save_uint_16(buf + 4, tran->blue);
@@ -1765,7 +1768,7 @@ png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,
       png_write_compressed_data_out(png_ptr, &comp);
 
    else
-      png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.input_len);
+      png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.output_len);
 
    png_write_chunk_end(png_ptr);
 }
@@ -1961,6 +1964,10 @@ png_write_start_row(png_structrp png_ptr)
    png_alloc_size_t buf_size;
    int usr_pixel_depth;
 
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+   png_byte filters;
+#endif
+
    png_debug(1, "in png_write_start_row");
 
    usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
@@ -1971,50 +1978,54 @@ png_write_start_row(png_structrp png_ptr)
    png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
 
    /* Set up row buffer */
-   png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size);
+   png_ptr->row_buf = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
 
    png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
 
 #ifdef PNG_WRITE_FILTER_SUPPORTED
-   /* Set up filtering buffer, if using this filter */
-   if (png_ptr->do_filter & PNG_FILTER_SUB)
-   {
-      png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1);
+   filters = png_ptr->do_filter;
 
-      png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
-   }
+   if (png_ptr->height == 1)
+      filters &= 0xff & ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+   if (png_ptr->width == 1)
+      filters &= 0xff & ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
+
+   if (filters == 0)
+      filters = PNG_FILTER_NONE;
 
-   /* We only need to keep the previous row if we are using one of these. */
-   if ((png_ptr->do_filter &
-      (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
+   png_ptr->do_filter = filters;
+
+   if (((filters & (PNG_FILTER_SUB | PNG_FILTER_UP | PNG_FILTER_AVG |
+       PNG_FILTER_PAETH)) != 0) && png_ptr->try_row == NULL)
    {
-      /* Set up previous row buffer */
-      png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);
+      int num_filters = 0;
 
-      if ((png_ptr->do_filter & PNG_FILTER_UP) != 0)
-      {
-         png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
-            png_ptr->rowbytes + 1);
+      png_ptr->try_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
 
-         png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
-      }
+      if (filters & PNG_FILTER_SUB)
+         num_filters++;
 
-      if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0)
-      {
-         png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
-             png_ptr->rowbytes + 1);
+      if (filters & PNG_FILTER_UP)
+         num_filters++;
 
-         png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
-      }
+      if (filters & PNG_FILTER_AVG)
+         num_filters++;
 
-      if ((png_ptr->do_filter & PNG_FILTER_PAETH) != 0)
-      {
-         png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
-             png_ptr->rowbytes + 1);
+      if (filters & PNG_FILTER_PAETH)
+         num_filters++;
 
-         png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
-      }
+      if (num_filters > 1)
+         png_ptr->tst_row = png_voidcast(png_bytep, png_malloc(png_ptr,
+             buf_size));
    }
+
+   /* We only need to keep the previous row if we are using one of the following
+    * filters.
+    */
+   if ((filters & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
+      png_ptr->prev_row = png_voidcast(png_bytep,
+         png_calloc(png_ptr, buf_size));
 #endif /* WRITE_FILTER */
 
 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
@@ -2160,7 +2171,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
          {
             png_bytep sp;
             png_bytep dp;
-            int shift;
+            unsigned int shift;
             int d;
             int value;
             png_uint_32 i;
@@ -2198,7 +2209,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
          {
             png_bytep sp;
             png_bytep dp;
-            int shift;
+            unsigned int shift;
             int d;
             int value;
             png_uint_32 i;
@@ -2235,7 +2246,7 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
          {
             png_bytep sp;
             png_bytep dp;
-            int shift;
+            unsigned int shift;
             int d;
             int value;
             png_uint_32 i;
@@ -2310,50 +2321,181 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
 }
 #endif
 
+
 /* This filters the row, chooses which filter to use, if it has not already
  * been specified by the application, and then writes the row out with the
  * chosen filter.
  */
-static void
+static void /* PRIVATE */
 png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
    png_size_t row_bytes);
 
-#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
-#define PNG_HISHIFT 10
-#define PNG_LOMASK ((png_uint_32)0xffffL)
-#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+static png_size_t /* PRIVATE */
+png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
+    const png_size_t row_bytes, const png_size_t lmins)
+{
+   png_bytep rp, dp, lp;
+   png_size_t i;
+   png_size_t sum = 0;
+   int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
+        i++, rp++, dp++)
+   {
+      v = *dp = *rp;
+      sum += (v < 128) ? v : 256 - v;
+   }
+
+   for (lp = png_ptr->row_buf + 1; i < row_bytes;
+      i++, rp++, lp++, dp++)
+   {
+      v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+      sum += (v < 128) ? v : 256 - v;
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return (sum);
+}
+
+static png_size_t /* PRIVATE */
+png_setup_up_row(png_structrp png_ptr, const png_size_t row_bytes,
+    const png_size_t lmins)
+{
+   png_bytep rp, dp, pp;
+   png_size_t i;
+   png_size_t sum = 0;
+   int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < row_bytes;
+       i++, rp++, pp++, dp++)
+   {
+      v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+      sum += (v < 128) ? v : 256 - v;
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return (sum);
+}
+
+static png_size_t /* PRIVATE */
+png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
+      const png_size_t row_bytes, const png_size_t lmins)
+{
+   png_bytep rp, dp, pp, lp;
+   png_uint_32 i;
+   png_size_t sum = 0;
+   int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+        pp = png_ptr->prev_row + 1; i < bpp; i++)
+   {
+      v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+
+      sum += (v < 128) ? v : 256 - v;
+   }
+
+   for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
+   {
+      v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+          & 0xff);
+
+      sum += (v < 128) ? v : 256 - v;
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return (sum);
+}
+
+static png_size_t /* PRIVATE */
+png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
+    const png_size_t row_bytes, const png_size_t lmins)
+{
+   png_bytep rp, dp, pp, cp, lp;
+   png_size_t i;
+   png_size_t sum = 0;
+   int v;
+
+   png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
+
+   for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
+       pp = png_ptr->prev_row + 1; i < bpp; i++)
+   {
+      v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+
+      sum += (v < 128) ? v : 256 - v;
+   }
+
+   for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
+        i++)
+   {
+      int a, b, c, pa, pb, pc, p;
+
+      b = *pp++;
+      c = *cp++;
+      a = *lp++;
+
+      p = b - c;
+      pc = a - c;
+
+#ifdef PNG_USE_ABS
+      pa = abs(p);
+      pb = abs(pc);
+      pc = abs(p + pc);
+#else
+      pa = p < 0 ? -p : p;
+      pb = pc < 0 ? -pc : pc;
+      pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+      p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+      v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+
+      sum += (v < 128) ? v : 256 - v;
+
+      if (sum > lmins)  /* We are already worse, don't continue. */
+        break;
+   }
+
+   return (sum);
+}
+#endif /* WRITE_FILTER */
+
 void /* PRIVATE */
 png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
 {
-   png_bytep best_row;
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-   png_bytep prev_row, row_buf;
-   png_uint_32 mins, bpp;
+#ifndef PNG_WRITE_FILTER_SUPPORTED
+   png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1);
+#else
    png_byte filter_to_do = png_ptr->do_filter;
+   png_bytep row_buf;
+   png_bytep best_row;
+   png_uint_32 bpp;
+   png_size_t mins;
    png_size_t row_bytes = row_info->rowbytes;
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   int num_p_filters = png_ptr->num_prev_filters;
-#endif
 
    png_debug(1, "in png_write_find_filter");
 
-#ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-  if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS)
-  {
-     /* These will never be selected so we need not test them. */
-     filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH);
-  }
-#endif
-
    /* Find out how many bytes offset each pixel is */
    bpp = (row_info->pixel_depth + 7) >> 3;
 
-   prev_row = png_ptr->prev_row;
-#endif
-   best_row = png_ptr->row_buf;
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-   row_buf = best_row;
-   mins = PNG_MAXSUM;
+   row_buf = png_ptr->row_buf;
+   mins = PNG_SIZE_MAX - 256/* so we can detect potential overflow of the
+                               running sum */;
 
    /* The prediction method we use is to find which method provides the
     * smallest value when summing the absolute values of the distances
@@ -2383,57 +2525,37 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
    /* We don't need to test the 'no filter' case if this is the only filter
     * that has been chosen, as it doesn't actually do anything to the data.
     */
+   best_row = png_ptr->row_buf;
+
+
    if ((filter_to_do & PNG_FILTER_NONE) != 0 && filter_to_do != PNG_FILTER_NONE)
    {
       png_bytep rp;
-      png_uint_32 sum = 0;
+      png_size_t sum = 0;
       png_size_t i;
       int v;
 
-      for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
+      if (PNG_SIZE_MAX/128 <= row_bytes)
       {
-         v = *rp;
-         sum += (v < 128) ? v : 256 - v;
-      }
+         for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
+         {
+            /* Check for overflow */
+            if (sum > PNG_SIZE_MAX/128 - 256)
+               break;
 
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+            v = *rp;
+            sum += (v < 128) ? v : 256 - v;
+         }
+      }
+      else /* Overflow is not possible */
       {
-         png_uint_32 sumhi, sumlo;
-         int j;
-         sumlo = sum & PNG_LOMASK;
-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
-
-         /* Reduce the sum if we match any of the previous rows */
-         for (j = 0; j < num_p_filters; j++)
+         for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
          {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
-            {
-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
+            v = *rp;
+            sum += (v < 128) ? v : 256 - v;
          }
-
-         /* Factor in the cost of this filter (this is here for completeness,
-          * but it makes no sense to have a "cost" for the NONE filter, as
-          * it has the minimum possible computational cost - none).
-          */
-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
-             PNG_COST_SHIFT;
-
-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
-             PNG_COST_SHIFT;
-
-         if (sumhi > PNG_HIMASK)
-            sum = PNG_MAXSUM;
-
-         else
-            sum = (sumhi << PNG_HISHIFT) + sumlo;
       }
-#endif
+
       mins = sum;
    }
 
@@ -2441,553 +2563,109 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
    if (filter_to_do == PNG_FILTER_SUB)
    /* It's the only filter so no testing is needed */
    {
-      png_bytep rp, lp, dp;
-      png_size_t i;
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
-           i++, rp++, dp++)
-      {
-         *dp = *rp;
-      }
-
-      for (lp = row_buf + 1; i < row_bytes;
-         i++, rp++, lp++, dp++)
-      {
-         *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
-      }
-
-      best_row = png_ptr->sub_row;
+      (void) png_setup_sub_row(png_ptr, bpp, row_bytes, mins); 
+      best_row = png_ptr->try_row;
    }
 
    else if ((filter_to_do & PNG_FILTER_SUB) != 0)
    {
-      png_bytep rp, dp, lp;
-      png_uint_32 sum = 0, lmins = mins;
-      png_size_t i;
-      int v;
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      /* We temporarily increase the "minimum sum" by the factor we
-       * would reduce the sum of this filter, so that we can do the
-       * early exit comparison without scaling the sum each time.
-       */
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 lmhi, lmlo;
-         lmlo = lmins & PNG_LOMASK;
-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+      png_size_t sum;
+      png_size_t lmins = mins;
 
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
-            {
-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
-             PNG_COST_SHIFT;
-
-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
-             PNG_COST_SHIFT;
-
-         if (lmhi > PNG_HIMASK)
-            lmins = PNG_MAXSUM;
-
-         else
-            lmins = (lmhi << PNG_HISHIFT) + lmlo;
-      }
-#endif
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
-           i++, rp++, dp++)
-      {
-         v = *dp = *rp;
-
-         sum += (v < 128) ? v : 256 - v;
-      }
-
-      for (lp = row_buf + 1; i < row_bytes;
-         i++, rp++, lp++, dp++)
-      {
-         v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-
-         if (sum > lmins)  /* We are already worse, don't continue. */
-            break;
-      }
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 sumhi, sumlo;
-         sumlo = sum & PNG_LOMASK;
-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
-            {
-               sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
-             PNG_COST_SHIFT;
-
-         sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
-             PNG_COST_SHIFT;
-
-         if (sumhi > PNG_HIMASK)
-            sum = PNG_MAXSUM;
-
-         else
-            sum = (sumhi << PNG_HISHIFT) + sumlo;
-      }
-#endif
+      sum = png_setup_sub_row(png_ptr, bpp, row_bytes, lmins); 
 
       if (sum < mins)
       {
          mins = sum;
-         best_row = png_ptr->sub_row;
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
       }
    }
 
    /* Up filter */
    if (filter_to_do == PNG_FILTER_UP)
    {
-      png_bytep rp, dp, pp;
-      png_size_t i;
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
-          pp = prev_row + 1; i < row_bytes;
-          i++, rp++, pp++, dp++)
-      {
-         *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
-      }
-
-      best_row = png_ptr->up_row;
+      (void) png_setup_up_row(png_ptr, row_bytes, mins);
+      best_row = png_ptr->try_row;
    }
 
    else if ((filter_to_do & PNG_FILTER_UP) != 0)
    {
-      png_bytep rp, dp, pp;
-      png_uint_32 sum = 0, lmins = mins;
-      png_size_t i;
-      int v;
-
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 lmhi, lmlo;
-         lmlo = lmins & PNG_LOMASK;
-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
-            {
-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
-             PNG_COST_SHIFT;
-
-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
-             PNG_COST_SHIFT;
-
-         if (lmhi > PNG_HIMASK)
-            lmins = PNG_MAXSUM;
-
-         else
-            lmins = (lmhi << PNG_HISHIFT) + lmlo;
-      }
-#endif
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
-          pp = prev_row + 1; i < row_bytes; i++)
-      {
-         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
+      png_size_t sum;
+      png_size_t lmins = mins;
 
-         if (sum > lmins)  /* We are already worse, don't continue. */
-            break;
-      }
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 sumhi, sumlo;
-         sumlo = sum & PNG_LOMASK;
-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
-            {
-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
-             PNG_COST_SHIFT;
-
-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
-             PNG_COST_SHIFT;
-
-         if (sumhi > PNG_HIMASK)
-            sum = PNG_MAXSUM;
-
-         else
-            sum = (sumhi << PNG_HISHIFT) + sumlo;
-      }
-#endif
+      sum = png_setup_up_row(png_ptr, row_bytes, lmins); 
 
       if (sum < mins)
       {
          mins = sum;
-         best_row = png_ptr->up_row;
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
       }
    }
 
    /* Avg filter */
    if (filter_to_do == PNG_FILTER_AVG)
    {
-      png_bytep rp, dp, pp, lp;
-      png_uint_32 i;
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
-           pp = prev_row + 1; i < bpp; i++)
-      {
-         *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
-      }
-
-      for (lp = row_buf + 1; i < row_bytes; i++)
-      {
-         *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
-                 & 0xff);
-      }
-      best_row = png_ptr->avg_row;
+      (void) png_setup_avg_row(png_ptr, bpp, row_bytes, mins);
+      best_row = png_ptr->try_row;
    }
 
    else if ((filter_to_do & PNG_FILTER_AVG) != 0)
    {
-      png_bytep rp, dp, pp, lp;
-      png_uint_32 sum = 0, lmins = mins;
-      png_size_t i;
-      int v;
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 lmhi, lmlo;
-         lmlo = lmins & PNG_LOMASK;
-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
-            {
-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
-             PNG_COST_SHIFT;
-
-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
-             PNG_COST_SHIFT;
-
-         if (lmhi > PNG_HIMASK)
-            lmins = PNG_MAXSUM;
-
-         else
-            lmins = (lmhi << PNG_HISHIFT) + lmlo;
-      }
-#endif
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
-           pp = prev_row + 1; i < bpp; i++)
-      {
-         v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-      }
-
-      for (lp = row_buf + 1; i < row_bytes; i++)
-      {
-         v = *dp++ =
-             (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-
-         if (sum > lmins)  /* We are already worse, don't continue. */
-            break;
-      }
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 sumhi, sumlo;
-         sumlo = sum & PNG_LOMASK;
-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
-            {
-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
-             PNG_COST_SHIFT;
-
-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
-             PNG_COST_SHIFT;
+      png_size_t sum;
+      png_size_t lmins = mins;
 
-         if (sumhi > PNG_HIMASK)
-            sum = PNG_MAXSUM;
-
-         else
-            sum = (sumhi << PNG_HISHIFT) + sumlo;
-      }
-#endif
+      sum= png_setup_avg_row(png_ptr, bpp, row_bytes, lmins);
 
       if (sum < mins)
       {
          mins = sum;
-         best_row = png_ptr->avg_row;
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
+         {
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
+         }
       }
    }
 
    /* Paeth filter */
    if ((filter_to_do == PNG_FILTER_PAETH) != 0)
    {
-      png_bytep rp, dp, pp, cp, lp;
-      png_size_t i;
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
-          pp = prev_row + 1; i < bpp; i++)
-      {
-         *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
-      }
-
-      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
-      {
-         int a, b, c, pa, pb, pc, p;
-
-         b = *pp++;
-         c = *cp++;
-         a = *lp++;
-
-         p = b - c;
-         pc = a - c;
-
-#ifdef PNG_USE_ABS
-         pa = abs(p);
-         pb = abs(pc);
-         pc = abs(p + pc);
-#else
-         pa = p < 0 ? -p : p;
-         pb = pc < 0 ? -pc : pc;
-         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#endif
-
-         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
-
-         *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
-      }
-      best_row = png_ptr->paeth_row;
+      (void) png_setup_paeth_row(png_ptr, bpp, row_bytes, mins);
+      best_row = png_ptr->try_row;
    }
 
    else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
    {
-      png_bytep rp, dp, pp, cp, lp;
-      png_uint_32 sum = 0, lmins = mins;
-      png_size_t i;
-      int v;
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
-      {
-         int j;
-         png_uint_32 lmhi, lmlo;
-         lmlo = lmins & PNG_LOMASK;
-         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
-         {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
-            {
-               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
-         }
-
-         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
-             PNG_COST_SHIFT;
+      png_size_t sum;
+      png_size_t lmins = mins;
 
-         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
-             PNG_COST_SHIFT;
+      sum = png_setup_paeth_row(png_ptr, bpp, row_bytes, lmins);
 
-         if (lmhi > PNG_HIMASK)
-            lmins = PNG_MAXSUM;
-
-         else
-            lmins = (lmhi << PNG_HISHIFT) + lmlo;
-      }
-#endif
-
-      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
-          pp = prev_row + 1; i < bpp; i++)
-      {
-         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-      }
-
-      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
-      {
-         int a, b, c, pa, pb, pc, p;
-
-         b = *pp++;
-         c = *cp++;
-         a = *lp++;
-
-#ifndef PNG_SLOW_PAETH
-         p = b - c;
-         pc = a - c;
-#ifdef PNG_USE_ABS
-         pa = abs(p);
-         pb = abs(pc);
-         pc = abs(p + pc);
-#else
-         pa = p < 0 ? -p : p;
-         pb = pc < 0 ? -pc : pc;
-         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
-#endif
-         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
-#else /* SLOW_PAETH */
-         p = a + b - c;
-         pa = abs(p - a);
-         pb = abs(p - b);
-         pc = abs(p - c);
-
-         if (pa <= pb && pa <= pc)
-            p = a;
-
-         else if (pb <= pc)
-            p = b;
-
-         else
-            p = c;
-#endif /* SLOW_PAETH */
-
-         v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
-
-         sum += (v < 128) ? v : 256 - v;
-
-         if (sum > lmins)  /* We are already worse, don't continue. */
-            break;
-      }
-
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+      if (sum < mins)
       {
-         int j;
-         png_uint_32 sumhi, sumlo;
-         sumlo = sum & PNG_LOMASK;
-         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
-
-         for (j = 0; j < num_p_filters; j++)
+         best_row = png_ptr->try_row;
+         if (png_ptr->tst_row != NULL)
          {
-            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
-            {
-               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-
-               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
-                   PNG_WEIGHT_SHIFT;
-            }
+            png_ptr->try_row = png_ptr->tst_row;
+            png_ptr->tst_row = best_row;
          }
-
-         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
-             PNG_COST_SHIFT;
-
-         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
-             PNG_COST_SHIFT;
-
-         if (sumhi > PNG_HIMASK)
-            sum = PNG_MAXSUM;
-
-         else
-            sum = (sumhi << PNG_HISHIFT) + sumlo;
-      }
-#endif
-
-      if (sum < mins)
-      {
-         best_row = png_ptr->paeth_row;
       }
    }
-#endif /* WRITE_FILTER */
 
    /* Do the actual writing of the filtered row data from the chosen filter. */
    png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
 
-#ifdef PNG_WRITE_FILTER_SUPPORTED
-#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
-   /* Save the type of filter we picked this time for future calculations */
-   if (png_ptr->num_prev_filters > 0)
-   {
-      int j;
-
-      for (j = 1; j < num_p_filters; j++)
-      {
-         png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
-      }
-
-      png_ptr->prev_filters[j] = best_row[0];
-   }
-#endif
 #endif /* WRITE_FILTER */
 }
 
@@ -3003,6 +2681,7 @@ png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
 
    png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);
 
+#ifdef PNG_WRITE_FILTER_SUPPORTED
    /* Swap the current and previous rows */
    if (png_ptr->prev_row != NULL)
    {
@@ -3012,6 +2691,7 @@ png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
       png_ptr->prev_row = png_ptr->row_buf;
       png_ptr->row_buf = tptr;
    }
+#endif /* WRITE_FILTER */
 
    /* Finish row - updates counters and flushes zlib if last row */
    png_write_finish_row(png_ptr);
author	Jose Fonseca <jfonseca@vmware.com>	2015-11-23 22:18:54 +0000
committer	Jose Fonseca <jfonseca@vmware.com>	2015-11-23 22:19:57 +0000
commit	ce651a7711042301cbc9c6866be0eeb9e1ceab66 (patch)
tree	c92185c5b69d0fef7c81d9c5a719ee60bdc29466
parent	c4cf34616e7fcf726438ae69a4415338430ebd02 (diff)