ui/gfx/font_list_impl.h

   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 #ifndef UI_GFX_FONT_LIST_IMPL_H_
   6 #define UI_GFX_FONT_LIST_IMPL_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/memory/ref_counted.h"
  12
  13 namespace gfx {
  14
  15 class Font;
  16
  17 // FontListImpl is designed to provide the implementation of FontList and
  18 // intended to be used only from FontList.  You must not use this class
  19 // directly.
  20 //
  21 // FontListImpl represents a list of fonts either in the form of Font vector or
  22 // in the form of a string representing font names, styles, and size.
  23 //
  24 // FontListImpl could be initialized either way without conversion to the other
  25 // form. The conversion to the other form is done only when asked to get the
  26 // other form.
  27 //
  28 // For the format of font description string, see font_list.h for details.
  29 class FontListImpl : public base::RefCounted<FontListImpl> {
  30  public:
  31   // Creates a font list from a string representing font names, styles, and
  32   // size.
  33   explicit FontListImpl(const std::string& font_description_string);
  34
  35   // Creates a font list from font names, styles and size.
  36   FontListImpl(const std::vector<std::string>& font_names,
  37                int font_style,
  38                int font_size);
  39
  40   // Creates a font list from a Font vector.
  41   // All fonts in this vector should have the same style and size.
  42   explicit FontListImpl(const std::vector<Font>& fonts);
  43
  44   // Creates a font list from a Font.
  45   explicit FontListImpl(const Font& font);
  46
  47   // Returns a new FontListImpl with the same font names but resized and the
  48   // given style. |size_delta| is the size in pixels to add to the current font
  49   // size. |font_style| specifies the new style, which is a bitmask of the
  50   // values: Font::BOLD, Font::ITALIC and Font::UNDERLINE.
  51   FontListImpl* Derive(int size_delta, int font_style) const;
  52
  53   // Returns the height of this font list, which is max(ascent) + max(descent)
  54   // for all the fonts in the font list.
  55   int GetHeight() const;
  56
  57   // Returns the baseline of this font list, which is max(baseline) for all the
  58   // fonts in the font list.
  59   int GetBaseline() const;
  60
  61   // Returns the cap height of this font list.
  62   // Currently returns the cap height of the primary font.
  63   int GetCapHeight() const;
  64
  65   // Returns the expected number of horizontal pixels needed to display the
  66   // specified length of characters. Call GetStringWidth() to retrieve the
  67   // actual number.
  68   int GetExpectedTextWidth(int length) const;
  69
  70   // Returns the |gfx::Font::FontStyle| style flags for this font list.
  71   int GetFontStyle() const;
  72
  73   // Returns the font size in pixels.
  74   int GetFontSize() const;
  75
  76   // Returns the Font vector.
  77   const std::vector<Font>& GetFonts() const;
  78
  79   // Returns the first font in the list.
  80   const Font& GetPrimaryFont() const;
  81
  82  private:
  83   friend class base::RefCounted<FontListImpl>;
  84
  85   ~FontListImpl();
  86
  87   // Extracts common font height and baseline into |common_height_| and
  88   // |common_baseline_|.
  89   void CacheCommonFontHeightAndBaseline() const;
  90
  91   // Extracts font style and size into |font_style_| and |font_size_|.
  92   void CacheFontStyleAndSize() const;
  93
  94   // A vector of Font. If FontListImpl is constructed with font description
  95   // string, |fonts_| is not initialized during construction. Instead, it is
  96   // computed lazily when user asked to get the font vector.
  97   mutable std::vector<Font> fonts_;
  98
  99   // A string representing font names, styles, and sizes.
 100   // Please refer to the comments before class declaration for details on string
 101   // format.
 102   // If FontListImpl is constructed with a vector of font,
 103   // |font_description_string_| is not initialized during construction. Instead,
 104   // it is computed lazily when user asked to get the font description string.
 105   //
 106   // TODO(derat): Remove laziness so that this can be removed.
 107   mutable std::string font_description_string_;
 108
 109   // The cached common height and baseline of the fonts in the font list.
 110   mutable int common_height_;
 111   mutable int common_baseline_;
 112
 113   // Cached font style and size.
 114   mutable int font_style_;
 115   mutable int font_size_;
 116 };
 117
 118 }  // namespace gfx
 119
 120 #endif  // UI_GFX_FONT_LIST_IMPL_H_