aura: Make Linux UI text rendering match GTK Chrome OS.

ui/gfx/pango_util.cc

 // Copyright (c) 2012 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/pango_util.h"
 
 #include <cairo/cairo.h>
 #include <pango/pango.h>
 #include <pango/pangocairo.h>
 
@@ skipping 18 matching lines @@
 // Marker for accelerators in the text.
 const gunichar kAcceleratorChar = '&';
 
 // Multiply by the text height to determine how much text should be faded
 // when elliding.
 const double kFadeWidthFactor = 1.5;
 
 // End state of the elliding fade.
 const double kFadeFinalAlpha = 0.15;
 
-// Return |cairo_font_options|. If needed, allocate and update it based on
-// GtkSettings.
+// Return |cairo_font_options|. If needed, allocate and update it.
 cairo_font_options_t* GetCairoFontOptions() {
   // Font settings that we initialize once and then use when drawing text.
   static cairo_font_options_t* cairo_font_options = NULL;
 
   if (cairo_font_options)
     return cairo_font_options;
 
   cairo_font_options = cairo_font_options_create();
 
+#if defined(TOOLKIT_USES_GTK)
   gint antialias = 0;
   gint hinting = 0;
   gchar* hint_style = NULL;
   gchar* rgba_style = NULL;
 
-#if !defined(USE_WAYLAND) && defined(TOOLKIT_USES_GTK)
-  // TODO(xji): still has gtk dependency.
   GtkSettings* gtk_settings = gtk_settings_get_default();
   g_object_get(gtk_settings,
                "gtk-xft-antialias", &antialias,
                "gtk-xft-hinting", &hinting,
                "gtk-xft-hintstyle", &hint_style,
                "gtk-xft-rgba", &rgba_style,
                NULL);
-#endif
 
   // g_object_get() doesn't tell us whether the properties were present or not,
   // but if they aren't (because gnome-settings-daemon isn't running), we'll get
   // NULL values for the strings.
   if (hint_style && rgba_style) {
     if (!antialias) {
       cairo_font_options_set_antialias(cairo_font_options,
                                        CAIRO_ANTIALIAS_NONE);
     } else if (strcmp(rgba_style, "none") == 0) {
       cairo_font_options_set_antialias(cairo_font_options,
@@ skipping 26 matching lines @@
     } else if (strcmp(hint_style, "hintfull") == 0) {
       cairo_hint_style = CAIRO_HINT_STYLE_FULL;
     }
     cairo_font_options_set_hint_style(cairo_font_options, cairo_hint_style);
   }
 
   if (hint_style)
     g_free(hint_style);
   if (rgba_style)
     g_free(rgba_style);
+#else
+  // For non-GTK builds (read: Aura), use the same settings that were previously
+  // used for GTK Chrome OS builds: RGB subpixel rendering with strong hinting.
+  // Note: We should probably be getting per-font settings from FontConfig here,
+  // but this path will be made obsolete by http://crbug.com/105550.
+  cairo_font_options_set_antialias(cairo_font_options,
+                                   CAIRO_ANTIALIAS_SUBPIXEL);
+  cairo_font_options_set_subpixel_order(cairo_font_options,
+                                        CAIRO_SUBPIXEL_ORDER_RGB);
+  cairo_font_options_set_hint_style(cairo_font_options, CAIRO_HINT_STYLE_FULL);
+#endif
 
   return cairo_font_options;
 }
 
 // Returns the number of pixels in a point.
 // - multiply a point size by this to get pixels ("device units")
 // - divide a pixel size by this to get points
 float GetPixelsInPoint() {
   static float pixels_in_point = 1.0;
   static bool determined_value = false;
@@ skipping 256 matching lines @@
     // There are PANGO_SCALE Pango units in a device unit (pixel).
     size_in_pixels /= PANGO_SCALE;
   } else {
     // Otherwise, we need to convert from points.
     size_in_pixels = size_in_pixels * GetPixelsInPoint() / PANGO_SCALE;
   }
   return size_in_pixels;
 }
 
 }  // namespace gfx