Inconsistencies in transparency rendering
Environment/Versions
- GIMP version: 2.10.34
- Package: Self-compiled
- Operating System: Linux
Description of the bug
Checking the rendering of an alpha gradient in different conditions leads to different results. In particular an often used check (adding a white layer at the bottom) no longer works.
Reproduction
Is the bug reproducible? Yes
Reproduction steps:
- Open the attached GradientScale.xcf
- In
Preferences > Interface > Display > Transparency
, set the check style to "White only" - With the
Alpha Gradient
layer set toNormal
, toggle the visibility of theWhite
layer, the general aspect changes - With the
Alpha Gradient
layer set toNormal(l)
, toggle the visibility of theWhite
layer, the general aspect doesn't change. - Furthermore, with the
Alpha Gradient
layer set toNormal
and theWhite
layer invisible), export the image to PNG or WebP and display it over a white background in a browser, the output looks identical to the output of the "legacy" mode, and not to the "2.10" mode: (using this HTML and these two images:
…
Expected result:
Always the same image
Actual result:
Different rendering
Additional information
Looking over the "WhiteLayer" screenshot with the pointer dialog, and doing the reverse math, it appear that the alpha transparency is subject to some gamma correction, and frankly I have never understood why the transparency in 2.10 is rendered like this.
This may be the same problem as #5328
Edited by ofnuts