Transform tools don't add an alpha channel in 'None' interpolation
Submitted by Ingo Ruhnke
Link to original bug (#796078)
Description
The transform tools don't automatically add an alpha channel when the interpolation is set to 'None', but will do so in all other interpolation modes.
For reproduction:
- Create a new image with a single layer without an alpha channel
- Use one of the transform tools (rotate, shear, perspective) on that layer
If the tools blend mode is set Linear, Cubic, NoHalo or LoHalo, everything works as expected and an alpha channel will be automatically added to the layer. The sections that should be transparent, will be transparent.
However if switching the blend mode to None, an alpha channel will not be added and the transparent sections of the transformed layer will be filled with black instead.
Workaround: Manually adding an alpha channel before doing a transformation with 'None' interpolation and things will work as expected.
This issue can be reproduced with Gimp 2.10.0 (Ubuntu snap-package) and Gimp 2.8.22 (regular Ubuntu 18.04 package).
Version: 2.10.0