RenderTextHarfBuzz: Try fallback fonts of the Uniscribe font while shaping

ui/gfx/render_text_harfbuzz.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/render_text_harfbuzz.h"
 
 #include <limits>
 #include <map>
 
 #include "base/i18n/bidi_line_iterator.h"
@@ skipping 1086 matching lines @@
   FontRenderParams best_render_params;
   size_t best_missing_glyphs = std::numeric_limits<size_t>::max();
 
   if (CompareFamily(run, primary_font.GetFontName(),
                     primary_font.GetFontRenderParams(),
                     &best_family, &best_render_params, &best_missing_glyphs))
     return;
 
 #if defined(OS_WIN)
   Font uniscribe_font;
+  bool got_uniscribe_font = false;
   const base::char16* run_text = &(GetLayoutText()[run->range.start()]);
   if (GetUniscribeFallbackFont(primary_font, run_text, run->range.length(),
-                               &uniscribe_font) &&
-      CompareFamily(run, uniscribe_font.GetFontName(),
-                    uniscribe_font.GetFontRenderParams(),
-                    &best_family, &best_render_params, &best_missing_glyphs))
-    return;
+                               &uniscribe_font)) {
+    got_uniscribe_font = true;
+    if (CompareFamily(run, uniscribe_font.GetFontName(),
+                      uniscribe_font.GetFontRenderParams(),
+                      &best_family, &best_render_params, &best_missing_glyphs))
+      return;
+  }
 #endif
 
   // Skip the first fallback font, which is |primary_font|.
   std::vector<std::string> fallback_families =
       GetFallbackFontFamilies(primary_font.GetFontName());
   for (size_t i = 1; i < fallback_families.size(); ++i) {
     FontRenderParamsQuery query(false);
     query.families.push_back(fallback_families[i]);
     query.pixel_size = run->font_size;
     query.style = run->font_style;
     FontRenderParams fallback_render_params = GetFontRenderParams(query, NULL);
     if (CompareFamily(run, fallback_families[i], fallback_render_params,
                       &best_family, &best_render_params, &best_missing_glyphs))
       return;
   }
 
+  // Try fonts in the fallback list of the Uniscribe font.

[msw, 2014/10/27 17:28:51]

Shouldn't this be in an #if defined(OS_WIN) block?

[ckocagil, 2014/10/28 03:24:42]

Done.

+  if (got_uniscribe_font) {
+    fallback_families =
+        GetFallbackFontFamilies(uniscribe_font.GetFontName());
+    for (size_t i = 1; i < fallback_families.size(); ++i) {

[Daniel Erat, 2014/10/27 18:49:24]

there's a bunch of duplicated code here. is the GetFallbackFontFamilies() call
expensive, or could you just append this list to the primary font's fallbacks
and have a single loop?

[ckocagil, 2014/10/28 03:24:42]

Done.

+      FontRenderParamsQuery query(false);
+      query.families.push_back(fallback_families[i]);
+      query.pixel_size = run->font_size;
+      query.style = run->font_style;
+      FontRenderParams fallback_render_params =
+          GetFontRenderParams(query, NULL);
+      if (CompareFamily(run, fallback_families[i], fallback_render_params,
+                        &best_family, &best_render_params,
+                        &best_missing_glyphs))
+        return;
+    }
+  }
+
   if (!best_family.empty() &&
       (best_family == run->family ||
        ShapeRunWithFont(run, best_family, best_render_params)))
     return;
 
   run->glyph_count = 0;
   run->width = 0.0f;
 }
 
 bool RenderTextHarfBuzz::ShapeRunWithFont(internal::TextRunHarfBuzz* run,
@@ skipping 50 matching lines @@
       run->width = std::floor(run->width + 0.5f);
 #endif
   }
 
   hb_buffer_destroy(buffer);
   hb_font_destroy(harfbuzz_font);
   return true;
 }
 
 }  // namespace gfx