Bug 583250 – pango_font_metrics_get_approximate_char_width is wrong when LANG=fa_IR

When computing approximate char width for context metrics use the actual
size the sample string renders to.  Previously it was taking average
over all the fonts used by the sample str.

1 files changed, 10 insertions, 19 deletions

diff --git a/pango/pango-context.c b/pango/pango-context.c
index 0b70f596..c00338e0 100644
--- a/pango/pango-context.c
+++ b/pango/pango-context.c
@@ -1575,13 +1575,16 @@ get_base_metrics (PangoFontset *fontset)
 static void
 update_metrics_from_items (PangoFontMetrics *metrics,
 			   PangoLanguage    *language,
+			   const char       *text,
 			   GList            *items)
 
 {
   GHashTable *fonts_seen = g_hash_table_new (NULL, NULL);
-  int count = 0;
+  PangoGlyphString *glyphs = pango_glyph_string_new ();
   GList *l;
 
+  metrics->approximate_char_width = 0;
+
   for (l = items; l; l = l->next)
     {
       PangoItem *item = l->data;
@@ -1595,29 +1598,17 @@ update_metrics_from_items (PangoFontMetrics *metrics,
 	  /* metrics will already be initialized from the first font in the fontset */
 	  metrics->ascent = MAX (metrics->ascent, raw_metrics->ascent);
 	  metrics->descent = MAX (metrics->descent, raw_metrics->descent);
-
-	  if (count == 0)
-	    {
-	      metrics->approximate_char_width = raw_metrics->approximate_char_width;
-	      metrics->approximate_digit_width = raw_metrics->approximate_digit_width;
-	    }
-	  else
-	    {
-	      metrics->approximate_char_width += raw_metrics->approximate_char_width;
-	      metrics->approximate_digit_width += raw_metrics->approximate_digit_width;
-	    }
-	  count++;
 	  pango_font_metrics_unref (raw_metrics);
 	}
+
+      pango_shape (text + item->offset, item->length, &item->analysis, glyphs);
+      metrics->approximate_char_width += pango_glyph_string_get_width (glyphs);
     }
 
+  pango_glyph_string_free (glyphs);
   g_hash_table_destroy (fonts_seen);
 
-  if (count)
-    {
-      metrics->approximate_char_width /= count;
-      metrics->approximate_digit_width /= count;
-    }
+  metrics->approximate_char_width /= pango_utf8_strwidth (text);
 }
 
 /**
@@ -1671,7 +1662,7 @@ pango_context_get_metrics (PangoContext                 *context,
   sample_str = pango_language_get_sample_string (language);
   items = itemize_with_font (context, sample_str, 0, strlen (sample_str), desc);
 
-  update_metrics_from_items (metrics, language, items);
+  update_metrics_from_items (metrics, language, sample_str, items);
 
   g_list_foreach (items, (GFunc)pango_item_free, NULL);
   g_list_free (items);