emacs-29 dc78779c0c: Fix SVG scaling (bug#59802)

[Eli Zaretskii]

branch: emacs-29
commit dc78779c0cd1f057830458f341c280ddb6695409
Author: Manuel Giraud <manuel@ledu-giraud.fr>
Commit: Eli Zaretskii <eliz@gnu.org>

    Fix SVG scaling (bug#59802)
    
    Fix SVG scaling with librsvg>2.52 and SVG file with only one known
    dimension.
    
    * src/image.c (svg_load_image): Compute a percentage dimension with
    the other known dimension.
---
 src/image.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/image.c b/src/image.c
index 2436f78ac3..b881e43e95 100644
--- a/src/image.c
+++ b/src/image.c
@@ -11309,6 +11309,15 @@ svg_load_image (struct frame *f, struct image *img, 
char *contents,
                                                    img->face_font_size);
          viewbox_height = svg_css_length_to_pixels (iheight, dpi,
                                                     img->face_font_size);
+
+         /* Here one dimension could be zero because in percent unit.
+            So calculate this dimension with the other.  */
+         if (! (0 < viewbox_width) && (iwidth.unit == RSVG_UNIT_PERCENT))
+           viewbox_width = (viewbox_height * viewbox.width / viewbox.height)
+             * iwidth.length;
+         else if (! (0 < viewbox_height) && (iheight.unit == 
RSVG_UNIT_PERCENT))
+           viewbox_height = (viewbox_width * viewbox.height / viewbox.width)
+             * iheight.length;
        }
       else if (has_width && has_viewbox)
        {