On Wednesday, 19 July 2023 at 15:27:20 BST, Alexei Podtelezhnikov <[email protected]> wrote: > Hin-Tak,
> This is probably both a spec question & a technical question. What is the > recommendation for COLRv1 when the rendering target media is not capable of > color? > Are you asking about RGB to gray conversion? There are multiple specs with > slightly different formulas and barely noticeable differences, with and > without gamma correction. I’m is all pretty arbitrary without settled > consensus. > Gray = 0.3R + 0.6G + 0.1B > is good enough. I am talking about 32-bit RGBA to 8-bit gray conversion, and I gave two examples/directions - throwing away the RGB part (and use the alpha channel as a mask on the current foreground colour), or throw away the A part, and doing 24-bit colour to gray conversion like you suggested (or even just gray = (r+g+b)/3). There is probably also a complication in the 2nd case, for layered glyphs - do you throw away the alpha channel first and stack the resulting solid colours/gray on top of one another, or do the full 32-bit rendering, then throw away the alpha channel and collapse the 24-bit? Werner also raised an interesting point - there is provision for palette on dark background vs light background I think, but is there a way of indicating some palettes are colour-blind-friendly? In the western world, it can be as bad as 1 in 30 male Caucasians being colour-blind.
