bug#40845: SVG rendering issues

[Alan Third]

On Sat, Aug 22, 2020 at 07:54:48PM +0300, Eli Zaretskii wrote:
> > Date: Sat, 22 Aug 2020 18:15:15 +0200 (CEST)
> > From: Alan Third <alan@idiocy.org>
> > 
> > I still don't know how to use the mouse face. I couldn't see any way
> > to detect if it's in use when we first load the image in xdisp.c.
> 
> Can you please remind me what was the problem?  The bug discussion is
> very long, and I didn't have time/patience to find the mouse face
> bits.

No problem.

Basically, if you try Clement's original example, when you move the
mouse over the image the background colour doesn't change to match the
rest of the line.

I'm picking up the background colour from the face stored in "it" in
push_prefix_prop or handle_single_display_spec in xdisp.c. As far as I
can tell one or both of these are the only places we can define the
image with the face colours as this is where we actually load the
image. The problem is that I don't see any way to work out if the
current image should use the background colour from the mouse face.

I know that later on we can do (s->hl == DRAW_MOUSE_FACE), but I don't
think those structures are built yet?

I've fixed the mistakes you pointed out. Thanks.
-- 
Alan Third