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. horizontal_dlus_to_pixels(int dlus)25 int horizontal_dlus_to_pixels(int dlus) const { 26 return dlus * font_ref_->GetDluBaseX() / 4; 27 } vertical_dlus_to_pixels(int dlus)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 GetAverageCharacterWidth() const OVERRIDE; 62 virtual int GetStringWidth(const base::string16& text) const OVERRIDE; 63 virtual int GetExpectedTextWidth(int length) const OVERRIDE; 64 virtual int GetStyle() const OVERRIDE; 65 virtual std::string GetFontName() const OVERRIDE; 66 virtual std::string GetActualFontNameForTesting() const OVERRIDE; 67 virtual int GetFontSize() const OVERRIDE; 68 virtual NativeFont GetNativeFont() const OVERRIDE; 69 70 private: ~PlatformFontWin()71 virtual ~PlatformFontWin() {} 72 73 // Chrome text drawing bottoms out in the Windows GDI functions that take an 74 // HFONT (an opaque handle into Windows). To avoid lots of GDI object 75 // allocation and destruction, Font indirectly refers to the HFONT by way of 76 // an HFontRef. That is, every Font has an HFontRef, which has an HFONT. 77 // 78 // HFontRef is reference counted. Upon deletion, it deletes the HFONT. 79 // By making HFontRef maintain the reference to the HFONT, multiple 80 // HFontRefs can share the same HFONT, and Font can provide value semantics. 81 class HFontRef : public base::RefCounted<HFontRef> { 82 public: 83 // This constructor takes control of the HFONT, and will delete it when 84 // the HFontRef is deleted. 85 HFontRef(HFONT hfont, 86 int font_size, 87 int height, 88 int baseline, 89 int cap_height, 90 int ave_char_width, 91 int style); 92 93 // Accessors hfont()94 HFONT hfont() const { return hfont_; } height()95 int height() const { return height_; } baseline()96 int baseline() const { return baseline_; } cap_height()97 int cap_height() const { return cap_height_; } ave_char_width()98 int ave_char_width() const { return ave_char_width_; } style()99 int style() const { return style_; } font_name()100 const std::string& font_name() const { return font_name_; } font_size()101 int font_size() const { return font_size_; } requested_font_size()102 int requested_font_size() const { return requested_font_size_; } 103 104 // Returns the average character width in dialog units. 105 int GetDluBaseX(); 106 107 private: 108 friend class base::RefCounted<HFontRef>; 109 110 ~HFontRef(); 111 112 const HFONT hfont_; 113 const int font_size_; 114 const int height_; 115 const int baseline_; 116 const int cap_height_; 117 const int ave_char_width_; 118 const int style_; 119 // Average character width in dialog units. This is queried lazily from the 120 // system, with an initial value of -1 meaning it hasn't yet been queried. 121 int dlu_base_x_; 122 std::string font_name_; 123 124 // If the requested font size is not possible for the font, |font_size_| 125 // will be different than |requested_font_size_|. This is stored separately 126 // so that code that increases the font size in a loop will not cause the 127 // loop to get stuck on the same size. 128 int requested_font_size_; 129 130 DISALLOW_COPY_AND_ASSIGN(HFontRef); 131 }; 132 133 // Initializes this object with a copy of the specified HFONT. 134 void InitWithCopyOfHFONT(HFONT hfont); 135 136 // Initializes this object with the specified font name and size. 137 void InitWithFontNameAndSize(const std::string& font_name, 138 int font_size); 139 140 // Returns the base font ref. This should ONLY be invoked on the 141 // UI thread. 142 static HFontRef* GetBaseFontRef(); 143 144 // Creates and returns a new HFONTRef from the specified HFONT. 145 static HFontRef* CreateHFontRef(HFONT font); 146 147 // Creates a new PlatformFontWin with the specified HFontRef. Used when 148 // constructing a Font from a HFONT we don't want to copy. 149 explicit PlatformFontWin(HFontRef* hfont_ref); 150 151 // Reference to the base font all fonts are derived from. 152 static HFontRef* base_font_ref_; 153 154 // Indirect reference to the HFontRef, which references the underlying HFONT. 155 scoped_refptr<HFontRef> font_ref_; 156 157 DISALLOW_COPY_AND_ASSIGN(PlatformFontWin); 158 }; 159 160 } // namespace gfx 161 162 #endif // UI_GFX_PLATFORM_FONT_WIN_H_ 163