Re: Emacs canvas support

[Stefan Monnier]

> Now imagine there's a (graphical) line going from (text) display
> line 3 to 7. You are not implying that we have to segment that
> into four chunks, one per text line?

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.


        Stefan