This is a major change required by the new PNGv3 colour chunk precedence
rules. It **does not** change the libpng API (png.h) however it changes
the following handling of PNG files:
IFF the PNG file contains colour space information it changes from the
libpng v3 behaviour to the now compulsory PNG v3 behaviour:
1) libpng no longer invalidates colour space chunks because they are
inconsistent.
2) libpng no longer responds to the "png_get_" APIs positively if they
are not present in the PNG but can be deduced from the colour space
chunks that are present.
This adds APIs to get/set the two remaining new PNG-v3 colour space
chunks. The mDCV API matches that of cHRM. Both chunks support
floating point APIs (all values in the two chunks are real numbers).
Both chunks have a new encoded type, a four-digit-precision fixed-point
number, which cannot be represented in the existing `png_fixed_point`
type, so a `png_uint_32` is used.
Test examples for cICP, cLLI and mDCV are now in pngtest.png, and a
necessary change to the pngunknown.c test program has been made to
accomodate the additions.
Reviewed-by: Cosmin Truta <ctruta@gmail.com>
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
This chunk was added in the third edition of the PNG specification and
contains Coding Independent Code Points (related to color space
description). It is fairly simple as it only contains four fields of one
byte each: Colour Primaries, Transfer Function, Matrix Coefficients,
Video Full Range Flag.
The test file originally comes from the related WPT test case:
https://github.com/web-platform-tests/wpt/blob/master/png/support/cicp-display-p3.png
Note that I reencoded the file to make it match libpng's default
encoding parameters (it only modifies the IDAT chunk).
This is a cherry-pick of commit 65925ad4b2cbed934d5d850fe764dc46c4becbcb
from branch 'libpng18'.
Reviewed-by: John Bowler <jbowler@acm.org>
Reviewed-by: Chris Blume <ProgramMax@gmail.com>
Reviewed-by: Cosmin Truta <ctruta@gmail.com>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
The leading blank lines are apparently an artefact of an older source
control system. They are not required and they look like accidents,
because starting a source file with a blank line is not a regular habit
of software developers nowadays.
This is a cherry-pick of commit 37cc20add8fb5b83bb5299a26cd3b41e0f776017
from branch 'libpng18'.
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
Add special handling of the PNG_INFO_tRNS flag to png_get_valid() to
not report a canceled tRNS chunk as valid.
Fix https://github.com/glennrp/libpng/issues/482
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
In v1.6.0, size_t became a required type. It should be used
consistently. To maintain backwards compatibility, png_size_t
is still maintained in deprecated form.
in pngwrite.c, and made various other fixes to png_write_eXIf().
Eliminated png_ptr->num_exif member from pngstruct.h and added num_exif
to arguments for png_get_eXIf() and png_set_eXIf().
