bug#67794: 30.0.50; mouse-face is not respected on SVG images

[Manuel Giraud via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

[-- Attachment #1: Type: text/plain, Size: 865 bytes --]

Alan Third <alan@idiocy.org> writes:

[...]

> Thanks, that worked. It was fine in NS (under GNUstep no less! It's
> unusual for GNUstep to work when other things don't) but failed under
> GTK/Cairo.
>
> I believe that we need to do some final set-up for the image under
> X/GTK/whatever and it looks as though this is all that's needed:
>
>      id = lookup_image (f, s->img->spec, hlinfo->mouse_face_face_id);
>      s->img = IMAGE_FROM_ID (f, id);
>      prepare_image_for_display (f, s->img); <------
>
> Under X we need to send the image to the X server, and under Cairo it
> does some other stuff. That's what prepare_image_for_display does. It
> does nothing under NS, so the image worked fine under GNUstep.

Thank you Alan!  That does the trick.  So here is an updated version of
the patch that works with XRender (i'll test with cairo).
-- 
Manuel Giraud

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-Respect-mouse-face-on-image-glyphs-bug-67794.patch --]
[-- Type: text/x-patch, Size: 1163 bytes --]

From 10c123988308cea24384205d118af75fdc09635c Mon Sep 17 00:00:00 2001
From: Manuel Giraud <manuel@ledu-giraud.fr>
Date: Tue, 19 Dec 2023 12:25:24 +0100
Subject: [PATCH] Respect mouse-face on image glyphs (bug#67794)

* src/xdisp.c (draw_glyphs): Maybe update image glyphs with mouse face
features before drawing.
---
 src/xdisp.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/xdisp.c b/src/xdisp.c
index 75d769600c4..cd9ce57c0da 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -30985,6 +30985,21 @@ draw_glyphs (struct window *w, int x, struct glyph_row *row,
 	  }
     }
 
+  /* Update image glyphs with mouse face features.  */
+  if (hl == DRAW_MOUSE_FACE)
+    {
+      Mouse_HLInfo *hlinfo = MOUSE_HL_INFO (f);
+      for (s = head; s; s = s->next)
+	if (s->first_glyph->type == IMAGE_GLYPH)
+	  if (s->img)
+	    {
+	      ptrdiff_t id;
+	      id = lookup_image (f, s->img->spec, hlinfo->mouse_face_face_id);
+	      s->img = IMAGE_FROM_ID (f, id);
+	      prepare_image_for_display(f, s->img);
+	    }
+    }
+
   /* Draw all strings.  */
   for (s = head; s; s = s->next)
     FRAME_RIF (f)->draw_glyph_string (s);
-- 
2.43.0