ui/gfx/font_render_params_win.cc

   1 // Copyright 2014 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.h"
   6
   7 #include "base/memory/scoped_ptr.h"
   8 #include "base/memory/singleton.h"
   9 #include "ui/gfx/win/singleton_hwnd.h"
  10
  11 namespace gfx {
  12
  13 namespace {
  14
  15 // Caches font render params and updates them on system notifications.
  16 class CachedFontRenderParams : public gfx::SingletonHwnd::Observer {
  17  public:
  18   static CachedFontRenderParams* GetInstance() {
  19     return Singleton<CachedFontRenderParams>::get();
  20   }
  21
  22   const FontRenderParams& GetParams(bool for_web_contents) {
  23     if (params_)
  24       return *params_;
  25
  26     params_.reset(new FontRenderParams());
  27     params_->antialiasing = false;
  28     params_->subpixel_positioning = false;
  29     params_->autohinter = false;
  30     params_->use_bitmaps = false;
  31     params_->hinting = FontRenderParams::HINTING_MEDIUM;
  32     params_->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_NONE;
  33
  34     BOOL enabled = false;
  35     if (SystemParametersInfo(SPI_GETFONTSMOOTHING, 0, &enabled, 0) && enabled) {
  36       params_->antialiasing = true;
  37       // Subpixel positioning is not yet implemented for UI. crbug.com/389649
  38       params_->subpixel_positioning = for_web_contents;
  39
  40       UINT type = 0;
  41       if (SystemParametersInfo(SPI_GETFONTSMOOTHINGTYPE, 0, &type, 0) &&
  42           type == FE_FONTSMOOTHINGCLEARTYPE) {
  43         params_->subpixel_rendering = FontRenderParams::SUBPIXEL_RENDERING_RGB;
  44       }
  45     }
  46     gfx::SingletonHwnd::GetInstance()->AddObserver(this);
  47     return *params_;
  48   }
  49
  50  private:
  51   friend struct DefaultSingletonTraits<CachedFontRenderParams>;
  52
  53   CachedFontRenderParams() {}
  54   virtual ~CachedFontRenderParams() {
  55     // Can't remove the SingletonHwnd observer here since SingletonHwnd may have
  56     // been destroyed already (both singletons).
  57   }
  58
  59   virtual void OnWndProc(HWND hwnd,
  60                          UINT message,
  61                          WPARAM wparam,
  62                          LPARAM lparam) override {
  63     if (message == WM_SETTINGCHANGE) {
  64       params_.reset();
  65       gfx::SingletonHwnd::GetInstance()->RemoveObserver(this);
  66     }
  67   }
  68
  69   scoped_ptr<FontRenderParams> params_;
  70
  71   DISALLOW_COPY_AND_ASSIGN(CachedFontRenderParams);
  72 };
  73
  74 }  // namespace
  75
  76 FontRenderParams GetFontRenderParams(const FontRenderParamsQuery& query,
  77                                      std::string* family_out) {
  78   // Customized font rendering settings are not supported, only defaults.
  79   if (!query.is_empty() || family_out)
  80     NOTIMPLEMENTED();
  81   return CachedFontRenderParams::GetInstance()->GetParams(
  82       query.for_web_contents);
  83 }
  84
  85 }  // namespace gfx