Currently, Drawpile's Color Erase blend mode actually works like "color to alpha", which is not really what you want most of the time.
So, the Color Erase blend mode should be renamed to Color to Alpha and the Erase blend mode should get a color tolerance slider, akin to the fill tool, and then only erase colors that fall into this tolerance. Analogously, that should also be available for the Recolor blend mode, which would only change the color of stuff that falls into the tolerance.
This needs some thinking on how to present this extra parameter in the UI.
Separately from that, it also needs some thinking of how it can fit in the protocol in a sensible way, without increasing the size of every command sent.
Currently, Drawpile's Color Erase blend mode actually works like "color to alpha", which is not really what you want most of the time.
So, the Color Erase blend mode should be renamed to Color to Alpha and the Erase blend mode should get a color tolerance slider, akin to the fill tool, and then only erase colors that fall into this tolerance. Analogously, that should also be available for the Recolor blend mode, which would only change the color of stuff that falls into the tolerance.
This needs some thinking on how to present this extra parameter in the UI.
Separately from that, it also needs some thinking of how it can fit in the protocol in a sensible way, without increasing the size of every command sent.
Credit Meru and dAVePAGE for suggesting.