Highlights of the patch:
- Supersede MR !249
- Added FP16 and FP32 images support thus preserving HDR values (read / write, required libjxl 0.9+).
- Added Gray8 and Gray16 support (read / write).
- Indexed images are saved as Gray8 when palette is gray scale.
- Binary images are saved as Gray8 (does JXL natively support binary images?).
- Simplified writing process by partially removing the use of additional buffers.
- Added XMP metadata support by decoding/encoding Boxes.
- Changed maximum image size in pixels in accordance with JXL feature level 5 (still limited to 256 megapixels).
Compatibility:
- Older versions of this plugin load FP images correctly as UINT16 (obviously losing HDR info).
- HDR images saved with this patch are also loaded correctly by Gimp and Photoshop.
- Grayscale images saved with this patch are also loaded correctly by Gimp and Photoshop.
Compilation modifiers for cmake file:
- `JXL_HDR_PRESERVATION_DISABLED`: disable the FP support (behaves like previous versions).
- `JXL_DECODE_BOXES_DISABLED`: disable metadata reading (behaves like previous versions).
Let Qt rotate the image when the ImageAutotransform option is set to true.
In tests it also solves the image size control with the value returned by the options with certain rotations.
* speeds up incremental builds as changes to a header will not always
need the full mocs_compilation.cpp for all the target's headers rebuild,
while having a moc file sourced into a source file only adds minor
extra costs, due to small own code and the used headers usually
already covered by the source file, being for the same class/struct
* seems to not slow down clean builds, due to empty mocs_compilation.cpp
resulting in those quickly processed, while the minor extra cost of the
sourced moc files does not outweigh that in summary.
Measured times actually improved by some percent points.
(ideally CMake would just skip empty mocs_compilation.cpp & its object
file one day)
* enables compiler to see all methods of a class in same compilation unit
to do some sanity checks
* potentially more inlining in general, due to more in the compilation unit
* allows to keep using more forward declarations in the header, as with the
moc code being sourced into the cpp file there definitions can be ensured
and often are already for the needs of the normal class methods
To make the plugins fail to allocate if the image size is greater than QImageReader::allocationLimit() it is necessary to allocate the image with QImageIOHandler::allocateImage().
Note that not all plugins have been changed and some others are not tested in the CI (maybe due to missing libraries).
PS: the following message is printed by QImageIOHandler::allocateImage() if the size is exceeded: "qt.gui.imageio: QImageIOHandler: Rejecting image as it exceeds the current allocation limit of XXX megabytes"
New libjxl API changed the way how lossless 16bit depth images
must be encoded: codestream level 10 must be set,
which implies use of container format.
Unfortunately, there isn’t version number inside libjxl header yet,
so we must detect new version on cmake/PkgConfig level.
