Larger images in HEIF/AVIF/JPEG-XL format are opened with reduced resolution

[sobrus]

 * Pix version 2.8.7
 Distribution - Manjaro

Issue When opening larger images (for example 26Mpix photos from digital camera) converted to these formats, they are being displayed in significally reduced resolution compared to original JPEG. Reported image resolution is displayed properly, but image itself is downscaled. GIMP is able to open them correctly.

Steps to reproduce

1. Convert large image to AVIF/HEIF/JXL format using imagemagick convert command.
2. Try to view it using pix.
3. Compare zoom ratio against original image or zoom in to 1:1 view and compare images.
4. Open file with GIMP or xviewer to view full resolution AVIF/HEIF/JXL image.

Expected behaviour Images are displayed at their full resolution.

Other information This issue also affects gThumb, but xviewer (from x-apps as well) works OK.

[sobrus]

I've noticed strange behaviour

• if I try to load test 26Mpix JXL image directly by file association with pix - it loads with reduced resolution (and reduction size is not constant, sometimes decoded image even fails to fill 1440p screen, sometimes it's larger).
• if I load simple jpeg image, wait a moment, and then go to next image (which is this JXL image), it gets loaded with full resolution (usually, but not always!)

This is just my hard guess - It seems like there is some sort of soft deadline to load image - resolution gets reduced when it needs to be loaded and showed quickly, and it gets worse on application launch.

[clefebvre]

This is fixed on master after the gthumb 3.12 rebase.