view: multiple colours

[wezm]

New thoughts on how color could be used.... If the following is too complicated and deserves its own issue, say the word!

It would be helpful in some cases to specify a sequence/vector of color values for foreground, where each color value in order is mapped to the corresponding glyph image in the output. The use case I'm envisioning is that each output glyph has its own color, so it's again easy to tell that (for example) a ligature did or did not form.

Instances where the difference is small and hard to detect in a solid-black image are fairly common. There might also be occasions where overlapping glyphs make it impossible to tell (like a small diacritic plonked onto the body of the base glyph).

I think that discrete color lists would suffice; gradients and other things that plotting libraries offer don't seem like they'd apply. But there are perhaps questions that would need answering, like whether spaces or invisible/ignorables count and whether cycling through the list if there are more glyphs than colors is the only option or some other strategy would be useful to someone.

Originally posted by @n8willis in #27 (comment)