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 #ifndef UI_GFX_PLATFORM_FONT_WIN_H_ 6 #define UI_GFX_PLATFORM_FONT_WIN_H_ 7 8 #include <string> 9 10 #include "base/compiler_specific.h" 11 #include "base/memory/ref_counted.h" 12 #include "ui/gfx/gfx_export.h" 13 #include "ui/gfx/platform_font.h" 14 15 namespace gfx { 16 17 class GFX_EXPORT PlatformFontWin : public PlatformFont { 18 public: 19 PlatformFontWin(); 20 explicit PlatformFontWin(NativeFont native_font); 21 PlatformFontWin(const std::string& font_name, int font_size); 22 23 // Dialog units to pixels conversion. 24 // See http://support.microsoft.com/kb/145994 for details. 25 int horizontal_dlus_to_pixels(int dlus) const { 26 return dlus * font_ref_->GetDluBaseX() / 4; 27 } 28 int vertical_dlus_to_pixels(int dlus) const { 29 return dlus * font_ref_->height() / 8; 30 } 31 32 // Callback that returns the minimum height that should be used for 33 // gfx::Fonts. Optional. If not specified, the minimum font size is 0. 34 typedef int (*GetMinimumFontSizeCallback)(); 35 static GetMinimumFontSizeCallback get_minimum_font_size_callback; 36 37 // Callback that adjusts a LOGFONT to meet suitability requirements of the 38 // embedding application. Optional. If not specified, no adjustments are 39 // performed other than clamping to a minimum font height if 40 // |get_minimum_font_size_callback| is specified. 41 typedef void (*AdjustFontCallback)(LOGFONT* lf); 42 static AdjustFontCallback adjust_font_callback; 43 44 // Returns the font name for the system locale. Some fonts, particularly 45 // East Asian fonts, have different names per locale. If the localized font 46 // name could not be retrieved, returns GetFontName(). 47 std::string GetLocalizedFontName() const; 48 49 // Returns a derived Font with the specified |style| and with height at most 50 // |height|. If the height and style of the receiver already match, it is 51 // returned. Otherwise, the returned Font will have the largest size such that 52 // its height is less than or equal to |height| (since there may not exist a 53 // size that matches the exact |height| specified). 54 Font DeriveFontWithHeight(int height, int style); 55 56 // Overridden from PlatformFont: 57 virtual Font DeriveFont(int size_delta, int style) const OVERRIDE; 58 virtual int GetHeight() const OVERRIDE; 59 virtual int GetBaseline() const OVERRIDE; 60 virtual int GetCapHeight() const OVERRIDE; 61 virtual int GetExpectedTextWidth(int length) const OVERRIDE; 62 virtual int GetStyle() const OVERRIDE; 63 virtual std::string GetFontName() const OVERRIDE; 64 virtual std::string GetActualFontNameForTesting() const OVERRIDE; 65 virtual int GetFontSize() const OVERRIDE; 66 virtual const FontRenderParams& GetFontRenderParams() const OVERRIDE; 67 virtual NativeFont GetNativeFont() const OVERRIDE; 68 69 private: 70 virtual ~PlatformFontWin() {} 71 72 // Chrome text drawing bottoms out in the Windows GDI functions that take an 73 // HFONT (an opaque handle into Windows). To avoid lots of GDI object 74 // allocation and destruction, Font indirectly refers to the HFONT by way of 75 // an HFontRef. That is, every Font has an HFontRef, which has an HFONT. 76 // 77 // HFontRef is reference counted. Upon deletion, it deletes the HFONT. 78 // By making HFontRef maintain the reference to the HFONT, multiple 79 // HFontRefs can share the same HFONT, and Font can provide value semantics. 80 class GFX_EXPORT HFontRef : public base::RefCounted<HFontRef> { 81 public: 82 // This constructor takes control of the HFONT, and will delete it when 83 // the HFontRef is deleted. 84 HFontRef(HFONT hfont, 85 int font_size, 86 int height, 87 int baseline, 88 int cap_height, 89 int ave_char_width, 90 int style); 91 92 // Accessors 93 HFONT hfont() const { return hfont_; } 94 int height() const { return height_; } 95 int baseline() const { return baseline_; } 96 int cap_height() const { return cap_height_; } 97 int ave_char_width() const { return ave_char_width_; } 98 int style() const { return style_; } 99 const std::string& font_name() const { return font_name_; } 100 int font_size() const { return font_size_; } 101 int requested_font_size() const { return requested_font_size_; } 102 103 // Returns the average character width in dialog units. 104 int GetDluBaseX(); 105 106 private: 107 friend class base::RefCounted<HFontRef>; 108 109 ~HFontRef(); 110 111 const HFONT hfont_; 112 const int font_size_; 113 const int height_; 114 const int baseline_; 115 const int cap_height_; 116 const int ave_char_width_; 117 const int style_; 118 // Average character width in dialog units. This is queried lazily from the 119 // system, with an initial value of -1 meaning it hasn't yet been queried. 120 int dlu_base_x_; 121 std::string font_name_; 122 123 // If the requested font size is not possible for the font, |font_size_| 124 // will be different than |requested_font_size_|. This is stored separately 125 // so that code that increases the font size in a loop will not cause the 126 // loop to get stuck on the same size. 127 int requested_font_size_; 128 129 DISALLOW_COPY_AND_ASSIGN(HFontRef); 130 }; 131 132 // Initializes this object with a copy of the specified HFONT. 133 void InitWithCopyOfHFONT(HFONT hfont); 134 135 // Initializes this object with the specified font name and size. 136 void InitWithFontNameAndSize(const std::string& font_name, 137 int font_size); 138 139 // Returns the base font ref. This should ONLY be invoked on the 140 // UI thread. 141 static HFontRef* GetBaseFontRef(); 142 143 // Creates and returns a new HFONTRef from the specified HFONT. 144 static HFontRef* CreateHFontRef(HFONT font); 145 146 // Creates and returns a new HFONTRef from the specified HFONT. Uses provided 147 // |font_metrics| instead of calculating new one. 148 static HFontRef* CreateHFontRef(HFONT font, const TEXTMETRIC& font_metrics); 149 150 // Returns a largest derived Font whose height does not exceed the height of 151 // |base_font|. 152 static Font DeriveWithCorrectedSize(HFONT base_font); 153 154 // Creates a new PlatformFontWin with the specified HFontRef. Used when 155 // constructing a Font from a HFONT we don't want to copy. 156 explicit PlatformFontWin(HFontRef* hfont_ref); 157 158 // Reference to the base font all fonts are derived from. 159 static HFontRef* base_font_ref_; 160 161 // Indirect reference to the HFontRef, which references the underlying HFONT. 162 scoped_refptr<HFontRef> font_ref_; 163 164 DISALLOW_COPY_AND_ASSIGN(PlatformFontWin); 165 }; 166 167 } // namespace gfx 168 169 #endif // UI_GFX_PLATFORM_FONT_WIN_H_ 170
