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 #pragma once
   8
   9 #include <string>
  10
  11 #include "base/memory/ref_counted.h"
  12 #include "base/string16.h"
  13 #include "ui/base/ui_export.h"
  14 #include "ui/gfx/native_widget_types.h"
  15
  16 namespace gfx {
  17
  18 class Font;
  19
  20 class UI_EXPORT PlatformFont : public base::RefCounted<PlatformFont> {
  21  public:
  22   // Creates an appropriate PlatformFont implementation.
  23   static PlatformFont* CreateDefault();
  24   static PlatformFont* CreateFromNativeFont(NativeFont native_font);
  25   // Creates a PlatformFont implementation with the specified |font_name|
  26   // (encoded in UTF-8) and |font_size| in pixels.
  27   static PlatformFont* CreateFromNameAndSize(const std::string& font_name,
  28                                              int font_size);
  29
  30   // Returns a new Font derived from the existing font.
  31   // |size_delta| is the size in pixels to add to the current font.
  32   // The style parameter specifies the new style for the font, and is a
  33   // bitmask of the values: BOLD, ITALIC and UNDERLINED.
  34   virtual Font DeriveFont(int size_delta, int style) const = 0;
  35
  36   // Returns the number of vertical pixels needed to display characters from
  37   // the specified font.  This may include some leading, i.e. height may be
  38   // greater than just ascent + descent.  Specifically, the Windows and Mac
  39   // implementations include leading and the Linux one does not.  This may
  40   // need to be revisited in the future.
  41   virtual int GetHeight() const = 0;
  42
  43   // Returns the baseline, or ascent, of the font.
  44   virtual int GetBaseline() const = 0;
  45
  46   // Returns the average character width for the font.
  47   virtual int GetAverageCharacterWidth() const = 0;
  48
  49   // Returns the number of horizontal pixels needed to display the specified
  50   // string.
  51   virtual int GetStringWidth(const string16& text) const = 0;
  52
  53   // Returns the expected number of horizontal pixels needed to display the
  54   // specified length of characters. Call GetStringWidth() to retrieve the
  55   // actual number.
  56   virtual int GetExpectedTextWidth(int length) const = 0;
  57
  58   // Returns the style of the font.
  59   virtual int GetStyle() const = 0;
  60
  61   // Returns the font name in UTF-8.
  62   virtual std::string GetFontName() const = 0;
  63
  64   // Returns the font size in pixels.
  65   virtual int GetFontSize() const = 0;
  66
  67   // Returns the native font handle.
  68   virtual NativeFont GetNativeFont() const = 0;
  69
  70  protected:
  71   virtual ~PlatformFont() {}
  72
  73  private:
  74   friend class base::RefCounted<PlatformFont>;
  75 };
  76
  77 }  // namespace gfx
  78
  79 #endif  // UI_GFX_PLATFORM_FONT_H_
  80