remove alpha channel should not composite with background
GIMP version: master
Operating System: any
Package: irrelevant
Description of the bug
A layer that has transparency (an alpha channel) offers users the action remove alpha channel with the hint Remove transparency information from the layer
.
This raises the expectation that nothing in the other channels will change – only the alpha channel will be removed.
But in fact, the actual behaviour is very different: the background is used to composite over the remaining channels. That behaviour might be useful under many circumstances, but not all. And it is definitely not what is documented.
I propose the following changes to fix this:
- add a new operation that actually does what the current documentation says, i.e. just removing the alpha channel
- expose the new operation as a new action in the UI, with the current action's name and description
- replace the current action's name and description with a better fit, e.g. reduce alpha channel with the hint
Remove transparency information by compositing with the background
The implementation is in gimp_layer_remove_alpha.