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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_FONT_H_ | |
6 #define UI_GFX_FONT_H_ | |
7 | |
8 #include <string> | |
9 | |
10 #include "base/memory/ref_counted.h" | |
11 #include "base/strings/string16.h" | |
12 #include "ui/gfx/gfx_export.h" | |
13 #include "ui/gfx/native_widget_types.h" | |
14 | |
15 namespace gfx { | |
16 | |
17 struct FontRenderParams; | |
18 class PlatformFont; | |
19 | |
20 // Font provides a wrapper around an underlying font. Copy and assignment | |
21 // operators are explicitly allowed, and cheap. | |
22 // | |
23 // Figure of font metrics: | |
24 // +--------+-------------------+------------------+ | |
25 // | | | internal leading | | |
26 // | | ascent (baseline) +------------------+ | |
27 // | height | | cap height | | |
28 // | |-------------------+------------------+ | |
29 // | | descent (height - baseline) | | |
30 // +--------+--------------------------------------+ | |
31 class GFX_EXPORT Font { | |
32 public: | |
33 // The following constants indicate the font style. | |
34 enum FontStyle { | |
35 NORMAL = 0, | |
36 BOLD = 1, | |
37 ITALIC = 2, | |
38 UNDERLINE = 4, | |
39 }; | |
40 | |
41 // Creates a font with the default name and style. | |
42 Font(); | |
43 | |
44 // Creates a font that is a clone of another font object. | |
45 Font(const Font& other); | |
46 Font& operator=(const Font& other); | |
47 | |
48 // Creates a font from the specified native font. | |
49 explicit Font(NativeFont native_font); | |
50 | |
51 // Constructs a Font object with the specified PlatformFont object. The Font | |
52 // object takes ownership of the PlatformFont object. | |
53 explicit Font(PlatformFont* platform_font); | |
54 | |
55 // Creates a font with the specified name in UTF-8 and size in pixels. | |
56 Font(const std::string& font_name, int font_size); | |
57 | |
58 ~Font(); | |
59 | |
60 // Returns a new Font derived from the existing font. | |
61 // |size_delta| is the size in pixels to add to the current font. For example, | |
62 // a value of 5 results in a font 5 pixels bigger than this font. | |
63 // The style parameter specifies the new style for the font, and is a | |
64 // bitmask of the values: BOLD, ITALIC and UNDERLINE. | |
65 Font Derive(int size_delta, int style) const; | |
66 | |
67 // Returns the number of vertical pixels needed to display characters from | |
68 // the specified font. This may include some leading, i.e. height may be | |
69 // greater than just ascent + descent. Specifically, the Windows and Mac | |
70 // implementations include leading and the Linux one does not. This may | |
71 // need to be revisited in the future. | |
72 int GetHeight() const; | |
73 | |
74 // Returns the baseline, or ascent, of the font. | |
75 int GetBaseline() const; | |
76 | |
77 // Returns the cap height of the font. | |
78 int GetCapHeight() const; | |
79 | |
80 // Returns the expected number of horizontal pixels needed to display the | |
81 // specified length of characters. Call gfx::GetStringWidth() to retrieve the | |
82 // actual number. | |
83 int GetExpectedTextWidth(int length) const; | |
84 | |
85 // Returns the style of the font. | |
86 int GetStyle() const; | |
87 | |
88 // Returns the specified font name in UTF-8. | |
89 std::string GetFontName() const; | |
90 | |
91 // Returns the actually used font name in UTF-8. | |
92 std::string GetActualFontNameForTesting() const; | |
93 | |
94 // Returns the font size in pixels. | |
95 int GetFontSize() const; | |
96 | |
97 // Returns an object describing how the font should be rendered. | |
98 const FontRenderParams& GetFontRenderParams() const; | |
99 | |
100 // Returns the native font handle. | |
101 // Lifetime lore: | |
102 // Windows: This handle is owned by the Font object, and should not be | |
103 // destroyed by the caller. | |
104 // Mac: The object is owned by the system and should not be released. | |
105 // Gtk: This handle is created on demand, and must be freed by calling | |
106 // pango_font_description_free() when the caller is done using it or | |
107 // by using ScopedPangoFontDescription. | |
108 NativeFont GetNativeFont() const; | |
109 | |
110 // Raw access to the underlying platform font implementation. Can be | |
111 // static_cast to a known implementation type if needed. | |
112 PlatformFont* platform_font() const { return platform_font_.get(); } | |
113 | |
114 private: | |
115 // Wrapped platform font implementation. | |
116 scoped_refptr<PlatformFont> platform_font_; | |
117 }; | |
118 | |
119 } // namespace gfx | |
120 | |
121 #endif // UI_GFX_FONT_H_ | |
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