Re: Emacs canvas support

[tomas@tuxteam.de]

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On Wed, Apr 29, 2020 at 09:19:51PM -0400, Stefan Monnier wrote:
> > 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.

This is sounding more and more like a compositor :-)

Nit: perhaps we'd like to have pics below as well as above text.

Cheers
-- t

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