New drop shadow tool in Gimp 2.10 ignores alpha channel
GIMP version: 2.10.2
Operating System: Windows 10 Professional, x64, Version 10.0.17134 Build 17134
Package: Installer from gimp.org
Description of the bug
If you apply the new drop shadow filter to a layer it ignores its alpha channel and simply creates a rectangular shadow. The legacy drop shadow tool would spare out the transparent image parts, thus creating a "real shadow" of the objects depicted in the layer.
Reproduction
Is the bug reproducible? [Depends on Project / no pattern identified]
Reproduction steps:
- Load an image
- Load another image as a layer on top
- Create a layer mask for the top layer
- Make some parts of the top layer transparent
- Apply the layer mask
- Run the new drop shadow filter on the top layer
Expected result:
The top layer should cast a shadow on the background layer (as a separate, new layer in between the two previous layers), with "light" apparently shining through the transparent parts of the top layer, thus creating a shadow in the shape of the visible parts of the top layer.
Actual result:
A simple, rectangular shadow is cast in a new layer.
Additional information
It would be great, if the new drop shadow tool would not only consider alpha cannels, as the legacy one does, but if it would treat layer masks like alpha channels. You would not have to apply the layer mask then before using the filter, thus depriving yourself of the possibility of further editing the layer mask, at least without a reconversion of the alpha channel into a mask.