Whoops, just realised I sent my previous message to Werner alone rather than the whole list… let me re-send it:
A somewhat related question - colour fonts are used beyond emoji's. While there are 5 kinds of emoji fonts now, and most people are using one of 4... but if you check Google Fonts, there are 10 colour fonts, one is emoji, but 6 are Arabic (useful for annotating the Quran...) and 3 are Latin. So there are intentions for text fonts. A few percents of western male population is color-blind. Colour-blindness is one of the most common eye problems, after short-sightedness 😄. I’m colour-blind, but not sure I understand what you’re asking here. None of the colour fonts on Google Fonts seem obviously difficult to read for me. Let's assume that you can't discern colors A and B, where both map to exactly the same gray value C (or to almost identical values). If a glyph uses those two colours exclusively, you will have problems with both a colour and a gray-level version of it. I see the problem. Yes, I would indeed have trouble using such a font. But in that case I’m tempted to blame the designer: if they can’t be bothered to account for colourblindness, FreeType can’t do very much to compensate for that! (Unless it can? Maybe there’s scope to allow the user to remap colours, or to switch between the two greyscale modes Hin-Tak mentioned, in much the same way that they can, say, select hinting modes. But I don’t know how feasible this would be.) Regards, Brad
