Gimp export to PNG with "automatic pixel format" ignores alpha channel
Environment/Versions
- GIMP version: GIMP 2.10.32 (revision 1)
- Package: Installer from gimp.org
- Operating System: Windows
Description of the bug
I want to export layers of file shades_issue.xcf to PNG files for each separate layer. Doing it via "Export layers" or manually exporting single visible layer via "Export..." with "automatic pixel format" produces PNG files for respective layers, but after "cloudshades.008.png" layer, exported images are wrong (wrong_pictures.zip). They are pure black, without any alpha value. Changing "automatic pixel format" to any other containing alpha (8bpc or 16bpc with RGBA or GREYA) produces correct images (good_pictures.zip), with alpha.
Source file: shades_issue.xcf
Reproduction
Is the bug reproducible? Always
Reproduction steps:
- Open "shades_issue.xcf"
- Export layers via "Export layers" or manually export each layer via "Export..."
- Set "automatic pixel format" option in export options.
Expected result: Pictures with correct alpha good_pictures.zip
Actual result: Pictures with incorrect alpha wrong_pictures.zip
Additional information
No crashes and bug reports, everything other than output images is ok.