PNG_AFTER_IDAT was not set by the IDAT read code if unknown chunk
handling was turned on. This was hidden in the current tests by checks
within the text handling chunks. (For example, pngtest.png has a zTXt
chunk after IDAT.)
This change modifies both the sequential and the progressive reader to
reliably set PNG_AFTER_IDAT when the first non-IDAT chunk is seen and
before that chunk is processed.
The change is minimalist; PNG_HAVE_CHUNK_AFTER_IDAT can probably be
removed and replaced with PNG_AFTER_IDAT. Making the latter change is
something to be considered in libpng2.
Co-authored-by: Cosmin Truta <ctruta@gmail.com>
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
Internal changes only.
Move chunk length checks to fewer places:
Change `png_struct::user_chunk_malloc_max` to always have a non-zero
value, in order to avoid the need to check for zero in multiple places.
Add `png_chunk_max(png_ptr)`, a function-like macro defined in pngpriv.h
which expresses all the previous checks on the various USER_LIMITS and
system limitations. Replace the code which implemented such checks with
`png_chunk_max`.
Move the malloc limit length check in `png_read_chunk_header` to
`png_handle_chunk` and make it conditional on the chunk type.
Progressive reader: call `png_read_chunk_header`.
Correct the handling of pHYs.
Reviewed-by: Cosmin Truta <ctruta@gmail.com>
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
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>
Apply the following corrections and improvements:
* Add a validity check in `png_set_cICP`.
* Fix the ordering check in `png_handle_cICP`.
* Add a multiplicity check in `png_handle_cICP`.
* Optimize the implementation of `png_write_cICP`.
* Remove an unnecessary preprocessor guard from pngtest.c.
* Update the dependency declaration in pnglibconf.dfa.
* Fix the indentation where necessary.
This is a cherry-pick of commit c2a02691df1ecf51b7c97142752a7034350cb1f6
from branch 'libpng18'.
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>
Move the definitions of interlace arrays to the top of their respective
translation units, to reduce their repeated copying in various places of
the codebase.
TODO:
As they still exist in three copies, in pngpread.c, in pngrutil.c, and
in pngwutil.c, they should all be further moved to a common place.
This is a cherry-pick of commit 620a2b73b22df66ed099e1faacac2d92f48252b7
from branch 'libpng18'.
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>
In v1.6.0, compiler support for const became a requirement.
It should be used consistently. To maintain backwards compatibility,
PNG_CONST is still maintained in deprecated form.
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 libpng 1.6 zlib initialization was changed to use the window size in the zlib
stream, not a fixed value. This causes some invalid images, ones where CINFO is
too large, to display 'correctly' if the rest of the data is valid. This
provides a work-round for zlib versions where the error arises (ones that
support the API change to use the window size in the stream).
Signed-off-by: John Bowler <jbowler@acm.org>
function has apparently never been used. It was implemented
to support back-door modification of png_struct in libpng-1.4.x
but was apparently never tested (because it does nothing and cannot
do anything).
