ui/gfx/font_render_params_linux.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/gfx/font_render_params_linux.h"
   6
   7 #include "base/command_line.h"
   8 #include "base/logging.h"
   9 #include "ui/gfx/switches.h"
  10
  11 #if defined(TOOLKIT_GTK)
  12 #include <gtk/gtk.h>
  13 #else
  14 #include <fontconfig/fontconfig.h>
  15 #endif
  16
  17 #if defined(OS_LINUX) && defined(USE_AURA) && !defined(OS_CHROMEOS)
  18 #include "ui/gfx/linux_font_delegate.h"
  19 #endif
  20
  21 namespace gfx {
  22
  23 namespace {
  24
  25 bool SubpixelPositioningRequested(bool renderer) {
  26   return CommandLine::ForCurrentProcess()->HasSwitch(
  27       renderer ?
  28       switches::kEnableWebkitTextSubpixelPositioning :
  29       switches::kEnableBrowserTextSubpixelPositioning);
  30 }
  31
  32 // Initializes |params| with the system's default settings. |renderer| is true
  33 // when setting WebKit renderer defaults.
  34 void LoadDefaults(FontRenderParams* params, bool renderer) {
  35 #if defined(TOOLKIT_GTK)
  36   params->antialiasing = true;
  37   // TODO(wangxianzhu): autohinter is now true to keep original behavior
  38   // of WebKit, but it might not be the best value.
  39   params->autohinter = true;
  40   params->use_bitmaps = true;
  41   params->hinting = FontRenderParams::HINTING_SLIGHT;
  42   params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_NONE;
  43
  44   GtkSettings* gtk_settings = gtk_settings_get_default();
  45   CHECK(gtk_settings);
  46   gint gtk_antialias = 0;
  47   gint gtk_hinting = 0;
  48   gchar* gtk_hint_style = NULL;
  49   gchar* gtk_rgba = NULL;
  50   g_object_get(gtk_settings,
  51                "gtk-xft-antialias", &gtk_antialias,
  52                "gtk-xft-hinting", &gtk_hinting,
  53                "gtk-xft-hintstyle", &gtk_hint_style,
  54                "gtk-xft-rgba", &gtk_rgba,
  55                NULL);
  56
  57   // g_object_get() doesn't tell us whether the properties were present or not,
  58   // but if they aren't (because gnome-settings-daemon isn't running), we'll get
  59   // NULL values for the strings.
  60   if (gtk_hint_style && gtk_rgba) {
  61     params->antialiasing = gtk_antialias;
  62
  63     if (gtk_hinting == 0 || strcmp(gtk_hint_style, "hintnone") == 0)
  64       params->hinting = FontRenderParams::HINTING_NONE;
  65     else if (strcmp(gtk_hint_style, "hintslight") == 0)
  66       params->hinting = FontRenderParams::HINTING_SLIGHT;
  67     else if (strcmp(gtk_hint_style, "hintmedium") == 0)
  68       params->hinting = FontRenderParams::HINTING_MEDIUM;
  69     else if (strcmp(gtk_hint_style, "hintfull") == 0)
  70       params->hinting = FontRenderParams::HINTING_FULL;
  71
  72     if (strcmp(gtk_rgba, "none") == 0)
  73       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_NONE;
  74     else if (strcmp(gtk_rgba, "rgb") == 0)
  75       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_RGB;
  76     else if (strcmp(gtk_rgba, "bgr") == 0)
  77       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_BGR;
  78     else if (strcmp(gtk_rgba, "vrgb") == 0)
  79       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_VRGB;
  80     else if (strcmp(gtk_rgba, "vbgr") == 0)
  81       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_VBGR;
  82   }
  83
  84   g_free(gtk_hint_style);
  85   g_free(gtk_rgba);
  86 #else
  87   // For non-GTK builds (read: Aura), just use reasonable hardcoded values.
  88   params->antialiasing = true;
  89   params->autohinter = true;
  90   params->use_bitmaps = true;
  91   params->hinting = FontRenderParams::HINTING_SLIGHT;
  92
  93   // Fetch default subpixel rendering settings from FontConfig.
  94   FcPattern* pattern = FcPatternCreate();
  95   FcConfigSubstitute(NULL, pattern, FcMatchPattern);
  96   FcDefaultSubstitute(pattern);
  97   FcResult result;
  98   FcPattern* match = FcFontMatch(0, pattern, &result);
  99   DCHECK(match);
 100   int fc_rgba = FC_RGBA_RGB;
 101   FcPatternGetInteger(match, FC_RGBA, 0, &fc_rgba);
 102   FcPatternDestroy(pattern);
 103   FcPatternDestroy(match);
 104
 105   switch (fc_rgba) {
 106     case FC_RGBA_RGB:
 107       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_RGB;
 108       break;
 109     case FC_RGBA_BGR:
 110       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_BGR;
 111       break;
 112     case FC_RGBA_VRGB:
 113       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_VRGB;
 114       break;
 115     case FC_RGBA_VBGR:
 116       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_VBGR;
 117       break;
 118     default:
 119       params->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_NONE;
 120   }
 121
 122 #if defined(OS_LINUX) && defined(USE_AURA) && !defined(OS_CHROMEOS)
 123   const LinuxFontDelegate* delegate = LinuxFontDelegate::instance();
 124   if (delegate) {
 125     params->antialiasing = delegate->UseAntialiasing();
 126     params->hinting = delegate->GetHintingStyle();
 127     params->subpixel_rendering = delegate->GetSubpixelRenderingStyle();
 128   }
 129 #endif
 130 #endif
 131
 132   params->subpixel_positioning = SubpixelPositioningRequested(renderer);
 133
 134   // To enable subpixel positioning, we need to disable hinting.
 135   if (params->subpixel_positioning)
 136     params->hinting = FontRenderParams::HINTING_NONE;
 137 }
 138
 139 }  // namespace
 140
 141 const FontRenderParams& GetDefaultFontRenderParams() {
 142   static bool loaded_defaults = false;
 143   static FontRenderParams default_params;
 144   if (!loaded_defaults)
 145     LoadDefaults(&default_params, /* renderer */ false);
 146   loaded_defaults = true;
 147   return default_params;
 148 }
 149
 150 const FontRenderParams& GetDefaultWebKitFontRenderParams() {
 151   static bool loaded_defaults = false;
 152   static FontRenderParams default_params;
 153   if (!loaded_defaults)
 154     LoadDefaults(&default_params, /* renderer */ true);
 155   loaded_defaults = true;
 156   return default_params;
 157 }
 158
 159 bool GetDefaultWebkitSubpixelPositioning() {
 160   return SubpixelPositioningRequested(true);
 161 }
 162
 163 }  // namespace gfx