Comment 37 for bug 499113

Created an attachment (id=358765)
WIP 0.000001: Move away from using the green channel as the alpha

Extremely-early preview of what I am working on right now.
With this patch, testcases involving extreme colors (white-on-white, black-on-black, #ff0000 on #ff0000, #00ffff on #00ffff) pass, but other tests still show errors, and real-life rendering is also still wrong. This is because the dummy maximum algorithm used in this patch is just a placeholder, and is definitely not correct. However, the basic structure of the _compute_argb32_mask_alpha function is in place, only an alpha-channel generation algorithm is needed. I think I need to convert the RGB colors to HSL and use the lightness value as the alpha, although I am not sure.

If you have an idea what the correct algorithm would be, please post it here!