cairo: Work harder to measure spacemore-space-tweaks

When coming up with a width for a missing space,
we were just measuring the hex digits. But in
subsetted fonts, such as the ones we use for ci,
hex digits might well be missing. Take that into
account and still provide some nonzero width
for space.

Update affected tests.

1 files changed, 21 insertions, 3 deletions

diff --git a/pango/pangocairo-font.c b/pango/pangocairo-font.c
index c2bcc51b..02a976d8 100644
--- a/pango/pangocairo-font.c
+++ b/pango/pangocairo-font.c
@@ -676,27 +676,45 @@ get_space_extents (PangoCairoFontPrivate *cf_priv,
                    PangoRectangle        *ink_rect,
                    PangoRectangle        *logical_rect)
 {
+  cairo_scaled_font_t *scaled_font;
   const char hexdigits[] = "0123456789ABCDEF";
   char c[2] = {0, 0};
   int i;
   double hex_width;
   int width;
+  int n_chars;
 
   /* we don't render missing spaces as hex boxes,
    * so come up with some width to use. For lack
    * of anything better, use average hex digit width.
    */
 
+  scaled_font = _pango_cairo_font_private_get_scaled_font (cf_priv);
   hex_width = 0;
+  n_chars = 0;
   for (i = 0 ; i < 16 ; i++)
     {
       cairo_text_extents_t extents;
 
       c[0] = hexdigits[i];
-      cairo_scaled_font_text_extents (_pango_cairo_font_private_get_scaled_font (cf_priv), c, &extents);
-      hex_width += extents.width;
+      cairo_scaled_font_text_extents (scaled_font, c, &extents);
+      if (extents.width > 0)
+        {
+          hex_width += extents.width;
+          n_chars++;
+        }
+    }
+
+  if (n_chars == 0)
+    {
+      cairo_font_extents_t extents;
+
+      cairo_scaled_font_extents (scaled_font, &extents);
+      hex_width += extents.max_x_advance;
+      n_chars++;
     }
-  width = pango_units_from_double (hex_width / 16);
+
+  width = pango_units_from_double (hex_width / n_chars);
 
   if (ink_rect)
     {