I have a PNG image. I want to use GraphicsMagick to convert all pixels with RGBA=(0, 0, 0, 0) (transparent over black) to be RGBA=(255, 255, 255, 0) (transparent over white). Is it possible to do this in GraphicsMagick?
my current command is:
gm convert orig.png -fill "#FFFFFF00" -opaque "#00000000" result.png
however, this doesn't work because for some reason the alpha channel on the replacement gets set to 100%. So, the actual fill ends up being #FFFFFFFF. Am I missing something?