I have one layer with some black pixels in the middle and a transparent background.
If I add an opaque white background under it, merge both, and then click “Antialias” from the “Filters” menu, it correctly generates gray pixels where appropriate. However, I intend to use this image on top of a dynamic background, so I can’t use anti-alias against a specific color, but if I don’t add the background opaque layer and just use the Antialias filter, nothing happens. My expectation was that semi-transparent pixels would be generated, so that it would become anti-aliased with different backgrounds.
Is there a way to achieve this or am I trying to do something wrong?
I still haven’t tested this, but I think I figured out a workaround. In troubleshooting another issue, I came to know the option “Color to Alpha”, which seems exactly what’s needed here. I think I can get Antialiasing like usual against one specific color and then use Color to Alpha to turn that color into different degrees of transparency. This would work fine on simple layers with very few colors, and it would probably be problematic in more busy patterns, but it fits my own needs at least.