Is there a way "Extract" a drop shadow in Paint.net?
For example:
I have a Gradient that is from Black to White. It represents a Drop Shadow on top of a White Background, (All in one layer. no transparency. kinda like if the Drop Shadow was "flattened", or you took a "Print Screen" of it). (left half of attached image)
How would you Convert that to a Gradient that is from Black to Transparent? Basically I want to replace White, and any level of "white" within the image, with that same level of Transparency. (right half of attached image)
Color Crosswalk:
Initial color -- post-extract color
(RRR-GGG-BBB-AAA) -- (RRR-GGG-BBB-AAA)
000-000-000-255 -- 000-000-000-255 (black stays black)
093-093-093-255 -- 000-000-000-163 (black, but a little bit transparent)
212-212-212-255 -- 000-000-000-044 (black, a little more transparent)
255-255-255-255 -- 000-000-000-000 (white turns into black, fully transparent)
Thank You,
Aaron