Closes#11
Requires MR !279
On formats that does not support CMYK and does not use the ScanLineConverter class during write operation, the CMYK images must be converted using the color space conversion functions of `QImage` (if ICC profile is valid).
* 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
Using C-API instead of C++ libheif API has following advantages:
- More libheif features available (for ex.: strict decoding)
- Linking with static build of libheif is possible
- No need to enable exceptions
In recent libheif, application should use
heif_init/heif_deinit calls. Unfortunately, these calls are
not thread-safe in released 1.13.0 version yet (will be in the
future) and HEIFHandler is often created in different threads.
So we have to guard their use with a mutex.
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"
