Re: Pixel-based display functions

[Eli Zaretskii]

> From: Lars Ingebrigtsen <address@hidden>
> Date: Fri, 30 Jan 2015 17:37:00 +1100
> 
> `font-get-glyphs' on a large region is quite fast, but since the font
> may vary, I'm calling it on a char-by-char basis, and that's s-l-o-w.

That's your problem: you should call it on a run of characters that
have the same face.  Use next-single-char-property-change to find
where such runs begin and end.

> `font-get-glyphs' returns an awful lot of data, and virtually all of it
> isn't used for doing this sort of filling, so I have a suspicion that
> I'm going to end up writing a new C-level function that just returns
> glyph widths fast.

That'd be a waste of effort, IMO.  Just do the above, and I think the
speed will be acceptable.