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
11namespace gfx {
12
13namespace {
14
15// Caches font render params and updates them on system notifications.
16class 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
76FontRenderParams 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
86