Qt 6.8 will introduce native support for the CMYK (8-bit) format.
With this patch you will finally be able to correctly see the colors of CMYK images with ICC profile.
The testing part has been updated with the addition of an (optional) json file for each image to test. Inside you enter which image to use depending on the Qt version.
In short:
- Added native CMYK suport to PSD reader
- CMYK with alpha is converted using QColorSpace in a RGBA image
- Read tests changed to use the correct comparison image based on the Qt version
- Fixed also XCF tests: now works with all Qt version (see also [QTBUG-120614](https://bugreports.qt.io/browse/QTBUG-120614))
- Work around for CCBUG: 468288
This is a patch over MR !108 by @sandsmark. Martin has done a great job implementing support and I find it a shame not to use it.
I made sure that the results are the same as the current version and fixed the problems of pixels with wrong colors with color depth grater than 8 bits. I also fixed conversion errors on mask and gray images (16/32 bits).
Unfortunately the internal rendering engine of the original code is 8-bit so I always forced the output of 8-bit images to correct the problems (see image below). Since it is a plugin with a "rendering engine", the tests to seriously validate it are potentially endless (as the original version is not perfect).
Errors of the original version of the MR (right) which should no longer occur:
- Fix parasite "gimp-comment" not set due to null QImage
- Support to parasite "icc-profile" using Qt 5.14+ API
- Added parasite "gimp-image-metadata" as QImage metadata "XML:org.gimp.xml"
- Added a XCF with XML metadata and icc prifile embedded in autotest folder (generated by GIMP 2.10.30)
- Tested with Qt 5.15.2 and Qt 6.2.3 under Windows and Qt 6.2.3 under macOS
We now support up to and including version 11 of the XCF format, earlier
it only supported version 1 (from 1997, according to the XCF spec).
Biggest difference seems to be that they changed to 64bit for offsets
from version 11 and upwards, otherwise it's mostly just newer enum
values and theoretically major stuff that we don't really need to care
about to get a thumbnail (e. g. linear vs. perceptual RGB).
We still don't support all features, but now it handles that more
gracefully and should at least create thumbnails that are usable. It
should also be easier to update in the future if/when there comes new
versions.
Also added a test file created with the latest version of Gimp
(2.10.18).
Reviewed By: aacid
Differential Revision: https://phabricator.kde.org/D25937
This fixes the xcf test that was failing, i guess at some point someone
run optipng or something over the expected result and that was causing
the test to fail
Two main tests: read the file and compare to a given image (loaded from
png), and write a file out and compare to a previously-written image.
The write test in particular is kind of fragile, but it should help
catch some errors where a code change was not intended to affect the
output of the plugin.
Tests are included for all the writable formats, as well as every
readable format that GIMP can write to (and so I could easily get an
example of).
REVIEW: 115430
