This patch removes the Use Alpha option from Composite and Viewer nodes.
The reasoning for the removal is as follows:
- It has an unintuitive complicated design at the moment.
- If the Alpha Input is unlinked, the output alpha is not adjusted
even if Use Alpha is enabled, leaving users wondering why their
adjustments have no effect.
- Disabled Use Alpha means output an opaque image, that is, it
actually means Ignore Alpha. Which is confusing because users might
think that it controls alpha adjustments based on input.
- It always does alpha replacement without premultiplication, which is
not clear to the user and is not what the user wants in most cases.
- Adding a Set Alpha node before the output is pretty easy and clear, so
the option seems redundant considering the above.
Pull Request: https://projects.blender.org/blender/blender/pulls/138309
4cb69dafb0