path: root/NEWS

Release 1.0.0 (2005-08-24 Carl Worth <cworth@cworth.org>)
=========================================================
Experimental backends
---------------------
 * The PS, PDF, Quartz, and XCB backends have been declared
   experimental, and are not part of the API guarantees that accompany
   this release. They are not built by default, even when the required
   libraries are available, and must be enabled explicitly with
   --enable-ps, --enable-pdf, --enable-quartz or --enable-xcb.

   It is very painful for us to be pushing out a major release without
   these backends enabled. There has been a tremendous amount of work
   put into each one and all are quite functional to some
   extent. However, each also has some limitations. And none of these
   backends have been tested to the level of completeness and
   correctness that we expect from cairo backends.

   We do encourage people to experiment with these backends and report
   sucess, failure, or means of improving them.

Operator behavior
-----------------
 * Prior to 0.9.0 the SOURCE, CLEAR and a number of other operators
   behaved in an inconsistent and buggy fashion and could affect areas
   outside the clip mask. In 0.9.0, these six "unbounded" operators
   were fixed to consistently clear areas outside the shape but within
   the clip mask.  This is useful behavior for an operator such as IN,
   but not what was expected for SOURCE and CLEAR. So, in this release
   the behavior of SOURCE and CLEAR has been changed again. They now
   affect areas only within both the source and shape. We can write
   the new operators as:

     SOURCE: dest' = (mask IN clip) ? source : dest
     CLEAR:  dest' = (mask IN clip) ? 0 : dest

Behavior and API changes
------------------------
 * Setting the filter on a gradient pattern would change the
   interpolation between color stops away from the normal linear
   interpolation. This dubious behavior has been removed.

 * The CAIRO_CONTENT_VALID() and CAIRO_FORMAT_VALID() macros --
   implementation details that leaked into cairo.h -- have been moved
   into an internal header.

 * The cairo_show_text function now advances the current point
   according to the total advance values of the string.

Features
--------
 * When compiled against recent versions of fontconfig and FreeType,
   artificial bold fonts can now be turned on from fonts.conf using
   the FC_EMBOLDEN fontconfig key.

Optimization
------------
 * The compositing code from the 'xserver' code tree has now been
   completely merged into libpixman. This includes MMX optimization of
   common operations.

 * The image transformation code in libpixman has been improved and
   now performs significantly faster.

Bug fixes
---------
 * Several crashes related to corruption in the font caches have been
   fixed.

 * All test cases now match pixel-for-pixel on x86 and PPC; this
   required fixing bugs in the compositing, stroking, and pattern
   rendering code.

 * Negative dash offsets have been fixed to work correctly.

 * The stroking of paths with mutiple subpaths has now been fixed to
   apply caps to all subpaths rather than just the last one.

 * Many build fixes for better portability on various systems.

 * Lots of other bug fixes, but we're too tired to describe them in
   more detail here.

Release 0.9.2 (2005-08-13 Carl Worth <cworth@cworth.org>)
=========================================================
Release numbering
-----------------
 * You will notice that this release jumped from 0.9.0 to 0.9.2. We've
   decided to use an odd micro version number (eg. 0.9.1) to indicate
   in-progress development between releases. As soon as 0.9.2 is
   tagged, the version will be incremented in CVS to 0.9.3 where it
   will stay until just before 0.9.4 is built, uploaded, and tagged.

   So, even-micro == a released version, odd-micro == something in-between.

Libpixman dependency dropped
----------------------------
 * As of this release, the dependency on an external libpixman has
   been dropped. Instead, the code from libpixman needed for cairo has
   been incorporated into the cairo source tree. The motivation for
   this change is that while cairo's API is stable and ready to be
   maintained after the 1.0 release, libpixman's API is not, so we do
   not want to expose it at this time.

   Also, the incorporation of libpixman into cairo also renames all
   previously-public libpixman symbols in order to avoid any conflict
   with a future release of libpixman

API additions
-------------
 * Macros and functions have been added so that the version of cairo
   can be queried at either compile-time or at run-time. The version
   is made available as both a human-readable string and as a single
   integer:

	CAIRO_VERSION_STRING		   eg. "0.9.2"
	CAIRO_VERSION			   eg. 000902

	const char*
	cairo_version_string (void);	/* eg. "0.9.2" */

	int
	cairo_version (void);		/* eg. 000902 */

   A macro is provided to convert a three-part component version into
   the encoded single-integer form:

	CAIRO_VERSION_ENCODE(X,Y,Z)

   For example, the CAIRO_VERSION value of 000902 is obtained as
   CAIRO_VERSION_ENCODE(0,9,2). The intent is to make version
   comparisons easy, either at compile-time:

	#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(0,9,2)
	...
	#endif

   Or at run-time:

	if (cairo_version() >= CAIRO_VERSION_ENCODE(0,9,2)) { /* ... */ }

Thread safety
-------------
 * This release adds pthread-based locking (when available) to make
   the caches used by cairo safe for threaded programs. Some may
   remember a failed experiment with this locking between the 0.5.1
   and 0.5.2 snapshots, (where even single-threaded programs that
   linked with -lpthread would deadlock). We believe that that problem
   has been fixed, so we are looking forward to testing and reports
   from users with threaded applications.

Bug fixes
---------
 * The XCB and Quartz backends failed to compiled in the 0.9.0 release
   due to minor syntax errors. These have now been fixed.

 * Various crashes in glitz and pixman due to size 0 glyphs have been
   fixed.

Release 0.9.0 (2005-08-08 Carl Worth <cworth@cworth.org>)
=========================================================
Soname change
-------------
 * In all prior snapshots, the libtool library versioning was set to
   1:0:0. As this release is intended to mark the beginning of
   backwards-compatible releases, the versioning has been incremented
   to 2:0:0. You will notice that the numeric extension on the
   installed library filename will change similarly.

   This change will also require all cairo-using applications to be
   recompiled. We recognize that this may cause some frustration since
   this release is backwards-compatible with 0.6.0 and in that sense
   "shouldn't" require re-compilation. However, since all historical
   snapshots have used the same 1:0:0 version in spite of incompatible
   API changes between them, it was essential that the upcoming 1.0
   release series have distinct library versioning.

   All future releases will use the library versioning to properly
   indicate compatibility between releases. So, any application
   re-compiled now to work with the 0.9.0 will not need to be
   recompiled when a compatible 1.0 release of cairo is made in the
   future.

API additions
-------------
 * Add new function calls to set/get the current antialiasing mode in
   the graphics state:

	cairo_set_antialias
	cairo_get_antialias

   This call accepts the same modes recently added for font options
   (NONE or GRAY) but affects the rendering of geometry other than
   text. The intent of this call is to enable more precise control of
   which pixels are affected by each operation, for example to allow
   for full-scene antialiasing for seam-free rendering. It is not
   expected that non-antialiased rendering will perform better than
   anti-aliased rendering.

 * Three new functions were added to provide support for mixed cairo-
   and non-cairo drawing to the same surface:

	cairo_surface_mark_dirty
	cairo_surface_mark_dirty_rectangle
	cairo_surface_flush

 * The return type of the several "reference" functions was change,
   (API compatibly), from void to the same type as the argument. The
   affected functions are:

	cairo_font_face_reference
	cairo_scaled_font_reference
	cairo_pattern_reference
	cairo_surface_reference
	cairo_reference

   This allows a convenient way to assign and reference in a single
   statement.

Semantic changes
----------------
 * The behavior of cairo_set_source with a pattern with a non-identity
   matrix was previously not well-defined. The new behavior is as
   follows:

	The pattern's transformation matrix will be locked to the
	user space in effect at the time of cairo_set_source(). This means
	that further modifications of the CTM will not affect the source
	pattern.

cairo-win32
-----------
 * Some portability improvements, (eg. workaround for missing stdint.h).

cairo-ft
--------
 * Updated to allow compilation with older versions of freetype.

Bug fixes
---------
 * Fix the unbounded operators to actually produce a correct result,
   (previously the results were artificially restricted to the
   bounding box of whatever shape was being drawn rather than
   extending out infinitely). The fixed operators are:

	CAIRO_OPERATOR_CLEAR
	CAIRO_OPERATOR_SOURCE
	CAIRO_OPERATOR_OUT
	CAIRO_OPERATOR_IN
	CAIRO_OPERATOR_DEST_IN
	CAIRO_OPERATOR_DEST_ATOP

 * Fix cairo_mask and cairo_mask_surface to transform the mask by the
   current transformation matrix (CTM).

 * Fix cairo_set_source to lock the CTM used to transform the pattern.

 * Workaround for X server Render bug involving repeating patterns
   with a general transformation matrix.

 * cairo_get_font_face fixed to return a "nil" font face object rather
   than NULL on error.

 * cairo_set_font_face fixed to not crash if given a NULL font face,
   (which is the documented interface for restoring the default font
   face).

 * Fix xlib glyphset caching to not try to free a NULL glyph.

Snapshot 0.6.0 (2005-07-28 Carl Worth <cworth@cworth.org>)
==========================================================
API changes
-----------
* The prototypes of the following functions have changed:

	cairo_xlib_surface_create_with_xrender_format
	cairo_xlib_surface_create_for_bitmap

  A Screen* parameter has been added to each. This allows the cairo
  xlib backend to work correctly with multi-head X servers.

* The following function has been modified:

	cairo_scaled_font_create

  to accept a cairo_font_options_t*. See below fore more details.

* All opaque, reference-counted cairo objects have now been moved to a
  standard error-handling scheme. The new objects to receive this
  treatment are cairo_font_face_t, cairo_scaled_font_t, and
  cairo_surface_t. (Previous snapshots already provided this scheme
  for cairo_t, cairo_path_t, and cairo_pattern_t.)

  This changes two functions to have a return type of void rather than
  cairo_status_t:

	cairo_scaled_font_extent
	cairo_surface_finish

  And significantly, none of the create functions for any of the
  objects listed above will return NULL. The pointer returned from any
  function will now always be a valid pointer and should always be
  passed to the corresponding destroy function when finished

  The simplest strategy for porting code is to switch from:

	object = cairo_<object>_create ();
	if (object == NULL)
	    goto BAILOUT;

	/* act on object */

	cairo_<object>_destroy (object);

  to:

	object = cairo_<object>_create ();
	if (cairo_<object>_status (object))
	    goto BAILOUT;

	/* act on object */

	cairo_<object>_destroy (object);

   But significantly, it is not required to check for an error status
   before the "act on object" portions of the code above. All
   operations on an object with an error status are, by definition,
   no-ops without side effect. So new code might be written in an
   easier-to-read style of:

	object = cairo_<object>_create ();

	/* act on object */

	cairo_<object>_destroy (object);

   with cairo_<object>_status checks placed only at strategic
   locations. For example, passing an error object to another object,
   (eg. cairo_set_source with an in-error pattern), will propagate the
   error to the subsequent object (eg. the cairo_t). This means that
   error checking can often be deferred even beyond the destruction of
   a temporary object.

API additions
-------------
* New functions for checking the status of objects that have been
  switched to the common error-handling scheme:

	cairo_font_face_status
	cairo_scaled_font_status
	cairo_surface_status

* The _cairo_error function which was added in 0.5.1 has now been made
  much more useful. In 0.5.1 only errors on cairo_t objects passed
  through _cairo_error. Now, an error on any object should pass
  through _cairo_error making it much more reliable as a debugging
  mechanism for finding when an error first occurs.

* Added new font options support with a myriad of functions:

	cairo_font_options_create
	cairo_font_options_copy
	cairo_font_options_destroy

	cairo_font_options_status

	cairo_font_options_merge
	cairo_font_options_equal
	cairo_font_options_hash

	cairo_font_options_set_antialias
	cairo_font_options_get_antialias
	cairo_font_options_set_subpixel_order
	cairo_font_options_get_subpixel_order
	cairo_font_options_set_hint_style
	cairo_font_options_get_hint_style
	cairo_font_options_set_hint_metrics
	cairo_font_options_get_hint_metrics

	cairo_surface_get_font_options

	cairo_ft_font_options_substitute

	cairo_set_font_options
	cairo_get_font_options

   This new font options support allows the application to have much
   more fine-grained control over how fonts are rendered.
   Significantly, it also allows surface backends to have some
   influence over the process. For example, the xlib backend now
   queries existing Xft properties to set font option defaults.

* New function:

	cairo_xlib_surface_set_drawable

  which allows the target drawable for an xlib cairo_surface_t to be
  changed to another with the same format, screen, and display. This
  is necessary in certain double-buffering techniques.

New features
------------
* Sub-pixel text antialiasing is now supported.

Bug fixes
---------
* Fixed assertion failure in cairo_surface_create_similar when
  application commits an error by passing a cairo_format_t rather than
  a cairo_content_t.

* Avoid division by zero in various places (cairo-ft).

* Fix infinite loop when using non-default visuals (cairo-xlib).

* Eliminate segfault in cairo_image_surface_create_from_png_stream.

* Prevent errant sign-extension of masks on 64-bit architectures
  (cairo-xlib and cairo-xcb).

* Other miscellaneous fixes.

Snapshot 0.5.2 (2005-07-18 Carl Worth <cworth@cworth.org>)
==========================================================
API changes
-----------
* New functions for creating patterns of a single color:

	cairo_pattern_create_rgb
	cairo_pattern_create_rgba

* Change cairo_surface_create_similar to accept a new type of
  cairo_content_t rather than cairo_format_t:

	typedef enum _cairo_content {
	    CAIRO_CONTENT_COLOR		= 0x1000,
	    CAIRO_CONTENT_ALPHA		= 0x2000,
	    CAIRO_CONTENT_COLOR_ALPHA	= 0x3000
	} cairo_content_t;

* Add new CAIRO_FORMAT_VALID and CAIRO_CONTENT_VALID macros.

* Remove unused status value:

	CAIRO_STATUS_NO_TARGET_SURFACE

* Add new status values:

	CAIRO_STATUS_INVALID_STATUS

* Require libpixman >= 0.1.5 (for necessary bug fixes)

Bug fixes
---------
* Fix cairo_surface_write_to_png for RGB24 images.

* Fix broken metrics and rendering for bitmap fonts. Add mostly
  useless bitmap glyph transformation.

* Fix glyph caches to not eject entries that might be immediately
  needed, (fixing intermittent crashes when rendering text).

* Fix all memory leaks found by running "make check-valgrind".

ATSUI backend changes
---------------------
* Allow building against < 10.3 SDK.

* Prevent crash on empty strings.

Glitz backend changes
---------------------
* Require glitz >= 0.4.4.

* Use frame buffer objects instead of pbuffers for accelerated
  offscreen drawing.

* Minor improvement to gradient pattern creation.

PostScript backend fixes
------------------------
* Rewrite of the PS backend to generate more interesting output that
  the old big-image implementation.

Win32 backend fixes
-------------------
* Implement glyph path support.

* Fix swap of blue and green values in the fill_rectangles path.

Xlib backend fixes
------------------
* Add optimization to use XCopyArea rather than XRenderComposite when
  transforming only with an integer translation, and using SOURCE
  operator or OVER with a source pattern without alpha.

Snapshot 0.5.1 (2005-06-20 Carl Worth <cworth@cworth.org>)
==========================================================
API changes
-----------
* Removed cairo_status_string(cairo_t*) and add
  cairo_status_to_string(cairo_status_t) in its place. Code using
  cairo_status_string can be ported forward as follows:

	cairo_status (cr);
	->
	cairo_status_to_string (cairo_status (cr));

* Removed the BAD_NESTING restriction which means that two different
  cairo_t objects can now interleave drawing to the same
  cairo_surface_t without causing an error.

* The following functions which previously had a return type of
  cairo_status_t now have a return type of void:

	cairo_pattern_add_color_stop_rgba
	cairo_pattern_set_matrix
	cairo_pattern_get_matrix
	cairo_pattern_set_extend
	cairo_pattern_set_filter

  See discussion of cairo_pattern_status below for more details.

API additions
-------------
* Improved error handling:

	cairo_status_t
	cairo_pattern_status (cairo_pattern_t *pattern);

  This snapshot expands the status-based error handling scheme from
  cairo_t to cairo_path_t and cairo_pattern_t. It also expands the
  scheme so that object-creating functions, (cairo_create,
  cairo_pattern_create_*, cairo_copy_path_*), are now guaranteed to
  not return NULL. Instead, in the case of out-of-memory these
  functions will return a static object with
  status==CAIRO_STATUS_NO_MEMORY. The status can be checked with the
  functions cairo_status and cairo_pattern_status, or by direct
  inspection of the new status field in cairo_path_t.

  Please note that some objects, including cairo_surface_t and all of
  the font-related objects have not been converted to this
  error-handling scheme.

* In addition to the above changes, a new private function has been added:

	_cairo_error

  This function can be used to set a breakpoint in a debugger to make
  it easier to find programming error in cairo-using code. (Currently,
  _cairo_error is called when any error is detected within a cairo_t
  context, but is not called for non-cairo_t errors such as for
  cairo_path_t and cairo_pattern_t).

* Fixed cairo_path_data_t so that its enum is visible to C++ code, (as
  cairo_path_data_type_t).

Performance improvements
------------------------
* Made a minor performance improvement for clipping, (restrict clip
  surface to the new intersected bounds).

* Optimize rendering of a solid source pattern with a pixel-aligned
  rectangular path to use backend clipping rather than rasterization
  and backend compositing.

* Optimize cairo_paint_with_alpha to defer to cairo_paint when alpha
  is 1.0.

Bug fixes
---------
* Fixed memory leak in cairo_copy_path.

* A build fix for non-srcdir builds.

PDF backend fixes
-----------------
* New support for path-based clipping.

* Fix for text rotated to angles other than multiples of π/2.

Win32 backend fixes
-------------------
* Fix for text extents.

Xlib backend
------------
* Implemented a complex workaround for X server bug[*] related to
  Render-based compositing with untransformed, repeating source
  pictures. The workaround uses core Xlib when possible for
  performance, (ie. with CAIRO_OPERATOR_SOURCE or CAIRO_OPERATOR_OVER
  with an opaque source surface), and falls back to the pixman
  image-based compositing otherwise.

  [*] https://bugs.freedesktop.org/show_bug.cgi?id=3566

* Various bug fixes, particularly in the fallback paths.

Snapshot 0.5.0 (2005-05-17 Carl Worth <cworth@cworth.org>)
==========================================================
This is a pretty big, and fairly significant snapshot.  It represents
between 2 and 3 months of solid work from a lot of people on improving
the API as much as possible. I'd like to express my appreciation and
congratulations to everyone who has worked on the big API Shakeup,
(whether in email battles over names, or fixing my silly bugs).

This snapshot will require some effort on the part of users, since
there are a _lot_ of API changes (ie. no cairo program ever written is
safe --- they're all broken now in at least one way). But, in spite of
that, we do encourage everyone to move their code to this snapshot as
soon as possible. And we're doing everything we can think of to make
the transition as smooth as possible.

The idea behind 0.5 is that we've tried to make every good API change
we could want now, and get them all done with. That is, between now
and the 1.0 release of cairo, we expect very few new API changes,
(though some will certainly sneak in). We will have some significant
additions, but the pain of moving code from cairo 0.4 to cairo 0.5
should be a one time experience, and things should be much smoother as
we continue to move toward cairo 1.0.

And with so many changes coming out for the first time in this 0.5
release, we really do need a lot of people trying this out to make
sure the ideas are solid before we freeze the API in preparation for
the 1.0 release.

OK, enough introduction. Here is a (not-quite-complete) description of
the API removals, changes and additions in this snapshot, (compared to
0.4.0)

API removals
============
The following public functions have been removed:

- cairo_set_target_*

	This is a big change. See the description of cairo_create in
	the API changes section for how to deal with this.

- cairo_set_alpha

	Alpha blending hasn't gone away; there's just a much more
	unified rendering model now. Almost all uses of
	cairo_set_alpha will be trivially replaced with
	cairo_set_source_rgba and a few others will be replaced just
	as easily with cairo_paint_with_alpha.

- cairo_show_surface

	Another useful function that we realized was muddling up the
	rendering model. The replacement is quite easy:
	cairo_set_source_surface and cairo_paint.

- cairo_matrix_create
- cairo_matrix_destroy
- cairo_matrix_copy
- cairo_matrix_get_affine

	These functions supported an opaque cairo_matrix_t. We now
	have an exposed cairo_matrix_t structure, so these can be
	dropped.

- cairo_surface_set_repeat
- cairo_surface_set_matrix
- cairo_surface_set_filter

	These properties don't belong on surfaces. If you were using
	them, you'll just want to instead use
	cairo_pattern_create_for_surface and then set these properties
	on the pattern.

- cairo_copy

	This was a confusing function and hopefully nobody will miss
	it. But if you really don't find cairo_save/restore adequate,
	let us know and we have another idea for a potential
	replacement.

And while we're on the subject of removals, we carefully tightened up
the cairo header files so they no longer gratuitously include header
files that are not strictly necessary, (stdio.h, stdint.h, pixman.h,
Xrender.h, etc. and their dependencies). This may lead to some
surprising errors, so keep your eyes open for that.

API changes
===========
Here are some of the API changes that have occurred:

~ cairo_create(void) -> cairo_create(cairo_surface_t *)

	This is the big change that breaks every program. The ability
	to re-target a cairo_t was not particularly useful, but it did
	introduce a lot of muddy semantic questions. To eliminate
	that, cairo_create now requires its target surface to be
	passed in at creation time. This isn't too hard to cope with
	as the typical first operation after cairo_create was often
	cairo_set_target_foo. So the order of those two swap and the
	application instead has cairo_foo_surface_create, then
	cairo_create.

~ cairo_current_* -> cairo_get_*

	We had a strange mixture of cairo_get and cairo_current
	functions. They've all been standardized on cairo_get, (though
	note one is cairo_get_current_point).

~ CAIRO_OPERATOR_SRC -> CAIRO_OPERATOR_SOURCE
~ CAIRO_OPERATOR_OVER_REVERSE -> CAIRO_OPERATOR_DEST_OVER

	Many of the cairo_operator_t symbolic values were renamed to
	reduce the amount of abbreviation. The confusing "OP_REVERSE"
	naming was also changed to use "DEST_OP" instead which is
	easier to read and has wider acceptance in other
	libraries/languages.

~ cairo_set_pattern -> cairo_set_source
~ cairo_set_rgb_color -> cairo_set_source_rgb

	All of the various functions that changed the source
	color/pattern were unified to use cairo_set_source names to
	make the relation more clear.

~ cairo_transform_point		   -> cairo_user_to_device
~ cairo_transform_distance	   -> cairo_user_to_device_distance
~ cairo_inverse_transform_point	   -> cairo_device_to_user
~ cairo_inverse_transform_distance -> cairo_device_to_user_distance

	These names just seemed a lot more clear.

~ cairo_init_clip	-> cairo_reset_clip
~ cairo_concat_matrix	-> cairo_transform

	More abbreviation elimination

~ cairo_current_path	  -> cairo_copy_path
~ cairo_current_path_flat -> cairo_copy_path_flat

	The former mechanism for examining the current path was a
	function that required 3 or 4 callbacks. This was more
	complexity than warranted in most situations. The new
	cairo_copy_path function copies the current path into an
	exposed data structure, and the documentation provides a
	convenient idiom for navigating the path data.

API additions
-------------
+ cairo_paint

	A generalized version of the painting operators cairo_stroke
	and cairo_fill. The cairo_paint call applies the source paint
	everywhere within the current clip region. Very useful for
	clearing a surface to a solid color, or painting an image,
	(see cairo_set_source_surface).

+ cairo_paint_with_alpha

	Like cairo_paint but applying some alpha to the source,
	(making the source paint translucent, eg. to blend an image on
	top of another).

+ cairo_mask

	A more generalized version of cairo_paint_with_alpha which
	allows a pattern to specify the amount of translucence at each
	point rather than using a constant value everywhere.

+ cairo_mask_surface

	A convenience function on cairo_mask for when the mask pattern
	is already contained within a surface.

+ cairo_surface_set_user_data
+ cairo_surface_get_user_data
+ cairo_font_face_set_user_data
+ cairo_font_face_get_user_data

	Associate arbitrary data with a surface or font face for later
	retrieval. Get notified when a surface or font face object is
	destroyed.

+ cairo_surface_finish

	Allows the user to instruct cairo to finish all of its
	operations for a given surface. This provides a safe point for
	doing things such as flushing and closing files that the
	surface may have had open for writing.

+ cairo_fill_preserve
+ cairo_stroke_preserve
+ cairo_clip_preserve

	One interesting change in cairo is that the path is no longer
	part of the graphics state managed by
	cairo_save/restore. This allows functions to construct paths
	without interfering with the graphics state. But it prevents
	the traditional idiom for fill-and-stroke:

		cairo_save; cairo_fill; cairo_restore; cairo_stroke

	Instead we know have alternate versions cairo cairo_fill,
	cairo_stroke, and cairo_clip that preserve the current path
	rather than consuming it. So the idiom now becomes simply:

		cairo_fill_preserve; cairo_stroke

+ cairo_surface_write_to_png
+ cairo_surface_write_to_png_stream

	In place of a single PNG backend, now a surface created
	through any backend (except PDF currently) can be written out
	to a PNG image.

+ cairo_image_surface_create_from_png
+ cairo_image_surface_create_from_png_stream

	And its just as easy to load a PNG image into a surface as well.

+ cairo_append_path

	With the new, exposed path data structure, it's now possible
	to append bulk path data to the current path, (rather than
	issuing a long sequence of cairo_move_to/line_to/curve_to
	function calls).

Xlib and XCB backends
---------------------

Any cairo_format_t and Colormap arguments have been dropped from
cairo_xlib_surface_create. There are also two new
cairo_xlib|xcb_surface_create functions:

	cairo_xlib|xcb_surface_create_for_bitmap
		(Particular for creating A1 surfaces)
	cairo_xlib|xcb_surface_create_with_xrender_format
		(For any other surface types, not described by a Visual*)

All of these surface create functions now accept width and height. In
addition, there are new cairo_xlib|xcb_surface_set_size functions
which must be called each time a window that is underlying a surface
changes size.

Print backends (PS and PDF)
---------------------------
The old FILE* based interfaces have been eliminated. In their place we
have two different functions. One accepts a simple const char
*filename. The other is a more general function which accepts a
callback write function and a void* closure. This should allow the
flexibility needed to hook up with various stream object in many
languages.

In addition, when specifying the surface size during construction, the
units are now device-space units (ie. points) rather than inches. This
provides consistency with all the other surface types and also makes
it much easier to reason about the size of the surface when drawing to
it with the default identity matrix.

Finally, the DPI parameters, which are only needed to control the
quality of fallbacks, have been made optional. Nothing is required
during surface_create (300 DPI is assumed) and
cairo_ps|pdf_surface_set_dpi can be used to set alternate values if
needed.

Font system
-----------
Owen very graciously listened to feedback after the big font rework he
had done for 0.4, and came up with way to improve it even more. In 0.4
there was a cairo_font_t that was always pre-scaled. Now, there is an
unscaled cairo_font_face_t which is easier to construct, (eg. no
scaling matrix required) and work with, (it can be scaled and
transformed after being set on the graphics state). And the font size
manipulation functions are much easier. You can set an explicit size
and read/modify/write the font matrix with:

	cairo_set_font_size
	cairo_get_font_matrix
	cairo_set_font_matrix

(Previously you could only multiply in a scale factor or a matrix.) A
pleasant side effect is that we can (and do) now have a default font
size that is reasonable, as opposed to the old default height of one
device-space unit which was useless until scaled.

Of course, the old pre-scaled font had allowed some performance
benefits when getting many metrics for a font. Those benefits are
still made available through the new cairo_scaled_font_t. And a
cairo_font_face_t can be "promoted" to a cairo_scaled_font_t by
suppling a font_matrix and the desired CTM.

Quartz backend
--------------
Tim Rowley put in the work to bring the Quartz backend back after it
had been disabled in the 0.4.0 snapshot. He was not able to bring back
the function that allows one to create a cairo_font_t from an ATSUI
style:

	cairo_font_t *
	cairo_atsui_font_create (ATSUStyle style);

because he didn't have a test case for it. If you care about this
function, please provide a fairly minimal test and we'll try to bring
it back in an upcoming snapshot.

Snapshot 0.4.0 (2005-03-08 Carl Worth <cworth@cworth.org>)
==========================================================
New documentation
-----------------
Owen Taylor has converted cairo's documentation system to gtk-doc and
has begun some long-needed work on the documentation, which can now be
viewed online here:

	http://cairographics.org/manual/

New backend: win32
------------------
This is the first snapshot to include a functional win32 backend,
(thanks to Owen Taylor). The interface is as follows:

	#include <cairo-win32.h>

	void 
	cairo_set_target_win32 (cairo_t *cr,
				HDC      hdc);

	cairo_surface_t *
	cairo_win32_surface_create (HDC hdc);

	cairo_font_t *
	cairo_win32_font_create_for_logfontw (LOGFONTW       *logfont,
					      cairo_matrix_t *scale);

	cairo_status_t
	cairo_win32_font_select_font (cairo_font_t *font,
				      HDC           hdc);

	void
	cairo_win32_font_done_font (cairo_font_t *font);

	double
	cairo_win32_font_get_scale_factor (cairo_font_t *font);

And see also the documentation at:

http://cairographics.org/manual/cairo-Microsoft-Windows-Backend.html

Disabled backend: quartz
------------------------
Unfortunately, the quartz backend code is currently out of date with
respect to some recent backend interface changes. So, the quartz
backend is disabled in this snapshot.

If the quartz backend is brought up-to-date before the next snapshot,
we would be glad to make a 0.4.1 snapshot that re-enables it, (we do
not expect many more big backend interface changes).

API Changes
-----------
The font system has been revamped, (as Owen Taylor's work with
integrating pango and cairo gave us the first serious usage of the
non-toy font API).

One fundamental, user-visible change is that the cairo_font_t object
now represents a font that is scaled to a particular device
resolution. Further changes are described below.

 cairo.h
 -------
 Removed cairo_font_set_transform and cairo_font_current_transform.

 Added cairo_font_extents and cairo_font_glyph_extents. See
 documentation for details:

 http://cairographics.org/manual/cairo-cairo-t.html#cairo-font-extents

 cairo-ft.h
 ----------
 The cairo_ft_font API changed considerably. Please see the
 documentation for details:

 http://cairographics.org/manual/cairo-FreeType-Fonts.html

Performance
-----------
Make the fast-path clipping (pixel-aligned rectangles) faster.

Add optimization for applying a constant alpha to a pattern.

Optimize gradients that are horizontal or vertical in device space.

Xlib: When RENDER is not available, use image surfaces for
intermediate surfaces rather than xlib surfaces.

Backend-specific changes
------------------------
 Glitz
 -----
 Major update to glitz backend. The output quality should now be just
 as good as the image and xlib backends.

 Track changes to glitz 0.4.0.

 PDF
 ---
 Various improvements to produce more conformant output.

Internals
---------
David Reveman contributed a large re-work of the cairo_pattern_t
implementation, providing cleaner code and more optimization
opportunities.

 Backend interface changes
 -------------------------
 Rework backend interface to accept patterns, not surfaces for source
 and mask.

 Remove set_matrix, set_filter, and set_repeat functions.

 More sophisticated backend interface for image fallbacks,
 ({acquire,release}_{source,dest}_image() and clone_similar).

Bug fixes
---------
Only install header files for backends that have been compiled.

Fixed some rounding errors leading to incorrectly placed glyphs.

Many other minor fixes.

Snapshot 0.3.0 (2005-01-21 Carl Worth <cworth@cworth.org>)
==========================================================
Major API changes
-----------------
1) The public header files will no longer be directly installed into
   the system include directory. They will now be installed in a
   subdirectory named "cairo", (eg. in /usr/include/cairo rather than
   in /usr/include).

   As always, the easiest way for applications to discover the
   location of the header file is to let pkg-config generate the
   necessary -I CFLAGS and -L/-l LDFLAGS. For example:

	cc `pkg-config --cflags --libs cairo` -o foo foo.c

   IMPORTANT: Users with old versions of cairo installed will need to
              manually remove cairo.h and cairo-features.h from the
              system include directories in order to prevent the old
              headers from being used in preference to the new ones.

2) The backend-specific portions of the old monolithic cairo.h have
   been split out into individual public header files. The new files
   are:

	cairo-atsui.h
        cairo-ft.h
        cairo-glitz.h
        cairo-pdf.h
        cairo-png.h
        cairo-ps.h
	cairo-quartz.h
        cairo-xcb.h
        cairo-xlib.h

   Applications will need to be modified to explicitly include the new
   header files where appropriate.

3) There are two new graphics backends in this snapshot, a PDF
   backend, and a Quartz backend. There is also one new font backend,
   ATSUI.

PDF backend
-----------
Kristian Høgsberg has contributed a new backend to allow cairo-based
applications to generate PDF output. The interface for creating a PDF
surface is similar to that of the PS backend, as can be seen in
cairo-pdf.h:

	void
	cairo_set_target_pdf (cairo_t	*cr,
			      FILE	*file,
			      double	width_inches,
			      double	height_inches,
			      double	x_pixels_per_inch,
			      double	y_pixels_per_inch);

	cairo_surface_t *
	cairo_pdf_surface_create (FILE		*file,
				  double	width_inches,
				  double	height_inches,
				  double	x_pixels_per_inch,
				  double	y_pixels_per_inch);

Once a PDF surface has been created, applications can draw to it as
any other cairo surface.

This code is still a bit rough around the edges, and does not yet
support clipping, surface patterns, or transparent gradients.  Text
only works with TrueType fonts at this point and only black text is
supported.  Also, the size of the generated PDF files is currently
quite big.

Kristian is still actively developing this backend, so watch this
space for future progress.

Quartz backend
--------------
Calum Robinson has contributed a new backend to allow cairo
applications to target native Mac OS X windows through the Quartz
API. Geoff Norton integrated this backend into the current
configure-based build system, while Calum also provided Xcode build
support in the separate "macosx" module available in CVS.

The new interface, available in cairo-quartz.h, is as follows:

	void
	cairo_set_target_quartz_context (cairo_t	*cr,
					 CGContextRef	context,
					 int		width,
					 int		height);

	cairo_surface_t *
	cairo_quartz_surface_create (CGContextRef context,
				     int	  width,
				     int	  height);

There is an example program available in CVS in cairo-demo/quartz. It
is a port of Keith Packard's fdclock program originally written for
the xlib backend. A screenshot of this program running on Mac OS X is
available here:

	http://cairographics.org/~cworth/images/fdclock-quartz.png

ATSUI font backend
------------------
This new font backend complements the Quartz backend by allowing
applications to use native font selection on Mac OS X. The interface
is a single new function:

	cairo_font_t *
	cairo_atsui_font_create (ATSUStyle style);

Minor API changes
-----------------
Prototype for non-existent function "cairo_ft_font_destroy" removed.

Now depends on libpixman 0.1.2 or newer, (0.1.3 is being released
concurrently and has some useful performance improvements).

Default paint color is now opaque black, (was opaque white). Default
background color is transparent (as before).

Renamed "struct cairo" to "struct _cairo" to free up the word "cairo"
from the C++ identifier name space.

Functions returning multiple return values through provided pointers,
(cairo_matrix_get_affine, cairo_current_point, and
cairo_current_color_rgb), will now accept NULL for values the user
wants to ignore.

CAIRO_HAS_FREETYPE_FONT has now been renamed to CAIRO_HAS_FT_FONT.

Performance improvements
------------------------
Alexander Larsson provided some fantastic performance improvements
yielding a 10000% performance improvement in his application, (when
also including his performance work in libpixman-0.1.3). These include

 * Fixed handling of cache misses.

 * Creating intermediate clip surfaces at the minimal size required.

 * Eliminating roundtrips when creating intermediate Xlib surfaces.

Implementation
--------------
Major re-work of font metrics system by Keith Packard. Font metrics
should now be much more reliable.

Glitz backend
-------------
Updated for glitz-0.3.0.
Bug fixes in reference counting.

Test suite
----------
New tests for cache crashing, rotating text, improper filling of
complex polygons, and leaky rasterization.

Bug fixes
---------
Fixed assertion failure when selecting the same font multiple times in
sequence.

Fixed reference counting so cache_destroy functions work.

Remove unintended copyright statement from files generated with
PostScript backend.

Fixed to eliminate new warnings from gcc 3.4 and gcc 4.

Snapshot 0.2.0 (2004-10-27 Carl Worth <cworth@cworth.org>)
===========================================================
New license: LGPL/MPL
---------------------
The most significant news with this release is that the license of
cairo has changed. It is now dual-licensed under the LGPL and the
MPL. For details see the COPYING file as well as COPYING-LGPL-2.1 and
COPYING-MPL-1.1.

I express my thanks to everyone involved in the license change process
for their patience and support!

New font and glyph internals
----------------------------
Graydon Hoare has put a tremendous amount of work into new internals
for handling fonts and glyphs, including caches where appropriate.
This work has no impact on the user-level API, but should result in
great performance improvements for applications using text.

New test suite
--------------
This snapshot of cairo includes a (small) test suite in
cairo/test. The tests can be run with "make check". The test suite was
designed to make it very easy to add new tests, and we hope to see
many contributions here. As you find bugs, please try adding a minimal
test case to the suite, and submit it with the bug report to the
cairo@cairographics.org mailing list. This will make it much easier
for us to track progress in fixing bugs.

New name for glitz backend
--------------------------
The gl backend has now been renamed to the glitz backend. This means
that the following names have changed:

	CAIRO_HAS_GL_SURFACE    -> CAIRO_HAS_GLITZ_SURFACE
	cairo_set_target_gl     -> cairo_set_target_glitz
	cairo_gl_surface_create -> cairo_glitz_surface_create

This change obviously breaks backwards compatibility for applications
using the old gl backend.

Up-to-date with latest glitz snapshots
--------------------------------------
This snapshot of cairo is now up to date with the latest glitz
snapshot, (currently 0.2.3). We know that the latest cairo and glitz
snapshots have been incompatible for a very long time. We've finally
fixed that now and we're determined to not let that happen again.

Revert some tessellation regression bugs
----------------------------------------
People that have been seeing some tessellation bugs, (eg. leaked
fills), in the CVS version of cairo may have better luck with this
release. A change since the last snapshot was identified to trigger
some of these bugs and was reverted before making the snapshot. The
behavior should be the same as the previous (0.1.23) snapshot.

Miscellaneous changes
---------------------
Changed CAIRO_FILTER_DEFAULT to CAIRO_FILTER_BEST to make gradients
easier.

Track XCB API change regarding iterators.

Various bug fixes
-----------------
Fix calculation of required number of vertices for pen.

Fix to avoid zero-dimensioned pixmaps.

Fix broken sort of pen vertices.

Fix bug when cairo_show_text called with a NULL string.

Fix clipping bugs.

Fix bug in computing image length with XCB.

Fix infinite loop bug in cairo_arc.

Fix memory management interactions with libpixman.

Snapshot 0.1.23 (2004-05-11 Carl Worth <cworth@isi.edu>)
========================================================
Fixes for gcc 3.4
-----------------
Fix prototype mismatches so that cairo can be built by gcc 3.4.

Updates to track glitz
----------------------
Various fixes to support the latest glitz snapshot (0.1.2).

Gradient updates
----------------
Radial gradients now support both inner and outer circles.
Transformed linear gradients are now properly handled.
Fixes for extend type reflect.

Glitz updates
-------------
Converted shading routines to use fixed point values and introduced a
shading operator structure for more efficient shading calculations.
Support compositing with mask surface when mask is solid or
multi-texturing is available.

PNG backend cleanups
--------------------
Fix output to properly compensate for pre-multiplied alpha format in cairo.
Add support for A8 and A1 image formats.

Bug fixes
---------
Avoid crash or infinite loop on null strings and degeneratively short
splines.

New? bugs in cairo_clip
-----------------------
There are some fairly serious bugs in cairo_clip. It is sometimes
causing an incorrect result. And even when it does work, it is
sometimes so slow as to be unusable. Some of these bugs may not be
new, (indeed cairo_clip has only ever had a braindead-slow
implementation), but I think they're worth mentioning here.

Snapshot 0.1.22 (2004-04-16 Carl Worth <cworth@isi.edu>)
========================================================
Cairo was updated to track the changes in libpixman, and now depends
on libpixman version 0.1.1.

Snapshot 0.1.21 (2004-04-09 David Reveman <c99drn@cs.umu.se>)
=============================================================
New OpenGL backend
------------------
The OpenGL backend provides hardware accelerated output for
X11 and OS X. The significant new functions are:

	cairo_set_target_gl
	cairo_gl_surface_create

Automatic detection of available backends
-----------------------------------------
The configure script now automatically detect what backends are
available, (use ./configure --disable-`backend' to prevent
compilation of specific backends).

Snapshot 0.1.20 (2004-04-06 Carl Worth <cworth@isi.edu>)
========================================================
New pattern API
---------------
David Reveman has contributed a new pattern API which enable linear
and radial gradient patterns in addition to the original surface-based
patterns. The significant new top-level functions are:

	cairo_pattern_create_linear
	cairo_pattern_create_radial
	cairo_pattern_create_for_surface
	cairo_pattern_add_color_stop
	cairo_set_pattern

Any code using the old cairo_set_pattern, (which accepted a
cairo_surface_t rather than a cairo_pattern_t), will need to be
updated.

Update to XCB backend
---------------------
The XCB backend is now enabled by default, (use ./configure
--disable-xcb to turn it off).

Faster clipping
---------------
Graydon Hoare has added optimizations that make cairo_clip much faster
when the path is a pixel-aligned, rectangular region.

Bug fixes.

Snapshot 0.1.19 (2004-02-24 Carl Worth <cworth@isi.edu>)
========================================================
New PNG backend
---------------
Olivier Andrieu contributed a new PNG backend. It builds on the
existing image backend to make it easy to render "directly" to a
.png file. The user never needs to deal with the actual image
buffer. The significant new functions are:

	cairo_set_target_png
	cairo_png_surface_create

The PNG backend is not enabled by default so that by default there is
not a new dependency on libpng. Use ./configure --enable-png to enable
this backend.

Snapshot 0.1.18 (2004-02-17 Carl Worth <cworth@isi.edu>)
========================================================
Path query functionality
------------------------
It's now possible to query the current path. The two new functions
are:

	cairo_current_path
	cairo_current_path_flat

Each function accepts a number of callback functions that will be
called for each element in the path (move_to, line_to, curve_to,
close_path). The cairo_current_path_flat function does not accept a
curve_to callback. Instead, all curved portions of the path will be
converted to line segments, (within the current tolerance value). This
can be handy for doing things like text-on-path without having to
manually interpolate Bézier splines.

New XCB backend
---------------
Jamey Sharp has contributed a second X backend that uses the new, lean
XCB library rather than Xlib. It cannot currently be compiled at the
same time as the Xlib backend. See ./configure --enable-xcb.

Build fixes for cygwin.

Bug fixes.

Snapshot 0.1.17 (2003-12-16 Carl Worth <cworth@isi.edu>)
========================================================

Better text support
-------------------
This snapshot provides much better text support by implementing the
following four functions:

        cairo_text_extents
        cairo_glyph_extents
        cairo_text_path
        cairo_glyph_path

The text/glyph_extents functions can be used to determine the bounding
box (and advance) for text as if drawn by show_text/glyphs.

The text/glyph_path objects functions place text shapes on the current
path, where they can be subsequently manipulated. For example,
following these functions with cairo_stroke allows outline text to be
drawn. Calling cairo_clip allows clipping to a text-shaped region.

Combined dependencies
---------------------
The cairo core now depends only on the libpixman library. This single
library replaces the three previous libraries libic, libpixregion, and
slim. Thanks to Dave Beckett <dave.beckett@bristol.ac.uk> for all of
the heavy lifting with this renaming effort.

Conditional compilation of backends
-----------------------------------
Cairo now allows optional backends to be disabled at compile time. The
following options may now be passed to the configure script:

	--disable-xlib
	--disable-ps

Note that the first option is a change from the old --without-x option
which will no longer have any effect.

OS X supported - several byte-order issues resolved
---------------------------------------------------
Cairo has now been successfully compiled under OS X. Testing revealed
that there were some byte-order problems in the PostScript backend and
the PNG generation in the demos. These have now been resolved.

2003-10
=======
Graydon Hoare <graydon@redhat.com> implemented the first real text
support using Freetype/fontconfig, (previous versions of cairo used
Xft and could only draw text when using an X backend).

2003-09
=======
Graydon Hoare <graydon@redhat.com> added the first real support for
running cairo with a non-render-aware X server.

Jamey Sharp <jamey@minilop.net> virtualized the backend font and
surface interfaces in September, 2003.

2003-06
=======
Xr is renamed cairo to avoid confusion since it no longer had a strict
dependence on X.

2003-05
=======
A new image surface backend is added to Xr. Keith Packard
<keithp@keithp.com> wrote the image compositing code in libic that is
used for the image_surface backend. This code was originally written
as the software fallback for the render extension within the X
server.

2002-06
=======
Carl Worth <cworth@isi.edu> wrote the first lines of Xr, after Keith
Packard <keithp@keithp.com> proposed the plan for a stateful drawing
library in C providing a PostScript-like rendering model.