ui/gfx/platform_font.h

   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_H_
   6 #define UI_GFX_PLATFORM_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 class Font;
  18
  19 class GFX_EXPORT PlatformFont : public base::RefCounted<PlatformFont> {
  20  public:
  21   // Creates an appropriate PlatformFont implementation.
  22   static PlatformFont* CreateDefault();
  23   static PlatformFont* CreateFromNativeFont(NativeFont native_font);
  24   // Creates a PlatformFont implementation with the specified |font_name|
  25   // (encoded in UTF-8) and |font_size| in pixels.
  26   static PlatformFont* CreateFromNameAndSize(const std::string& font_name,
  27                                              int font_size);
  28
  29   // Returns a new Font derived from the existing font.
  30   // |size_delta| is the size in pixels to add to the current font.
  31   // The style parameter specifies the new style for the font, and is a
  32   // bitmask of the values: BOLD, ITALIC and UNDERLINE.
  33   virtual Font DeriveFont(int size_delta, int style) const = 0;
  34
  35   // Returns the number of vertical pixels needed to display characters from
  36   // the specified font.  This may include some leading, i.e. height may be
  37   // greater than just ascent + descent.  Specifically, the Windows and Mac
  38   // implementations include leading and the Linux one does not.  This may
  39   // need to be revisited in the future.
  40   virtual int GetHeight() const = 0;
  41
  42   // Returns the baseline, or ascent, of the font.
  43   virtual int GetBaseline() const = 0;
  44
  45   // Returns the cap height of the font.
  46   virtual int GetCapHeight() const = 0;
  47
  48   // Returns the average character width for the font.
  49   virtual int GetAverageCharacterWidth() const = 0;
  50
  51   // Returns the number of horizontal pixels needed to display the specified
  52   // string.
  53   virtual int GetStringWidth(const base::string16& text) const = 0;
  54
  55   // Returns the expected number of horizontal pixels needed to display the
  56   // specified length of characters. Call GetStringWidth() to retrieve the
  57   // actual number.
  58   virtual int GetExpectedTextWidth(int length) const = 0;
  59
  60   // Returns the style of the font.
  61   virtual int GetStyle() const = 0;
  62
  63   // Returns the font name in UTF-8.
  64   virtual std::string GetFontName() const = 0;
  65
  66   // Returns the font size in pixels.
  67   virtual int GetFontSize() const = 0;
  68
  69   // Returns the native font handle.
  70   virtual NativeFont GetNativeFont() const = 0;
  71
  72  protected:
  73   virtual ~PlatformFont() {}
  74
  75  private:
  76   friend class base::RefCounted<PlatformFont>;
  77 };
  78
  79 }  // namespace gfx
  80
  81 #endif  // UI_GFX_PLATFORM_FONT_H_