RE: Emacs canvas support

[Drew Adams]

> I think it would make more sense to treat the overlaid canvas as
> a completely separate pixmap: when we get an request to redraw
> a particular area of the screen, we'd ask the current redisplay code to
> redraw the corresponding text content and then we'd ask the canvas code
> to draw on top of it.  So for rendering of the canvas code we don't
> need to know which part of the canvas cover which characters, we just
> render the glyph matrix into a pixmap, render the canvas into another
> pixmap and then combine them onto the screen.

Exactly what I was thinking/wondering, as someone
totally naive in this area.  If we're after a graphic
canvas (editing with pixels), why involve glyphs/chars
at all, for that space?