Re: Emacs canvas support

[Po Lu <luangruo@yahoo.com>]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> 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.

That's what I'm trying to do right now, but so far keeping track of
exactly where each canvas is displayed on the screen seems to be
difficult.  I'd appreciate some suggestions, thanks.