Merge branch 'ubuntu-patches'

1 files changed, 43 insertions, 7 deletions

diff --git a/jpegtran.1 b/jpegtran.1
index 4e5b33c..4809a94 100644
--- a/jpegtran.1
+++ b/jpegtran.1
@@ -91,12 +91,12 @@ Transpose image (across UL-to-LR axis).
 .TP
 .B \-transverse
 Transverse transpose (across UR-to-LL axis).
-.PP
+.IP
 The transpose transformation has no restrictions regarding image dimensions.
 The other transformations operate rather oddly if the image dimensions are not
 a multiple of the iMCU size (usually 8 or 16 pixels), because they can only
 transform complete blocks of DCT coefficient data in the desired way.
-.PP
+.IP
 .BR jpegtran 's
 default behavior when transforming an odd-size image is designed
 to preserve exact reversibility and mathematical consistency of the
@@ -108,7 +108,7 @@ able to flip all columns.  The other transforms can be built up as sequences
 of transpose and flip operations; for consistency, their actions on edge
 pixels are defined to be the same as the end result of the corresponding
 transpose-and-flip sequence.
-.PP
+.IP
 For practical use, you may prefer to discard any untransformable edge pixels
 rather than having a strange-looking strip along the right and/or bottom edges
 of a transformed image.  To do this, add the
@@ -117,7 +117,7 @@ switch:
 .TP
 .B \-trim
 Drop non-transformable edge blocks.
-.PP
+.IP
 Obviously, a transformation with
 .B \-trim
 is not reversible, so strictly speaking
@@ -130,6 +130,40 @@ trims only the bottom edge, but
 followed by
 .B \-rot 180 -trim
 trims both edges.
+.IP
+If you are only interested by perfect transformation, add the
+.B \-perfect
+switch:
+.TP
+.B \-perfect
+Fails with an error if the transformation is not perfect. For example
+you may want to do
+.IP
+.B (jpegtran \-rot 90 -perfect foo.jpg || djpeg foo.jpg| pnmflip \-r90 | cjpeg)
+.IP
+to do a perfect rotation if available or an approximated one if
+not.
+.PP
+We also offer a lossless-crop option, which discards data outside a given
+image region but losslessly preserves what is inside.  Like the rotate and
+flip transforms, lossless crop is restricted by the JPEG format: the upper
+left corner of the selected region must fall on an iMCU boundary.  If this
+does not hold for the given crop parameters, we silently move the upper left
+corner up and/or left to make it so, simultaneously increasing the region
+dimensions to keep the lower right crop corner unchanged.  (Thus, the
+output image covers at least the requested region, but may cover more.)
+.IP
+Note: 
+.B \-perfect
+and
+.B lossless-crop
+are enhancements from http://sylvana.net/jpegcrop/ that may not be available on
+non-Debian systems.
+.PP
+The image can be losslessly cropped by giving the switch:
+.TP
+.B \-crop WxH+X+Y
+Crop to a rectangular subarea of width W, height H starting at point X,Y.
 .PP
 If you are only interested by perfect transformation, add the
 .B \-perfect
@@ -169,7 +203,7 @@ Another not-strictly-lossless transformation switch is:
 .TP
 .B \-grayscale
 Force grayscale output.
-.PP
+.IP
 This option discards the chrominance channels if the input image is YCbCr
 (ie, a standard color JPEG), resulting in a grayscale JPEG file.  The
 luminance channel is preserved exactly, so this is a better method of reducing
@@ -193,9 +227,11 @@ but discards any other inessential data.
 .TP
 .B \-copy all
 Copy all extra markers.  This setting preserves miscellaneous markers
-found in the source file, such as JFIF thumbnails and Photoshop settings.
+found in the source file, such as
+Exif data,
+JFIF thumbnails and Photoshop settings.
 In some files these extra markers can be sizable.
-.PP
+.IP
 The default behavior is
 .BR "\-copy comments" .
 (Note: in IJG releases v6 and v6a,