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 struct FontRenderParams;
  19
  20 class GFX_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 UNDERLINE.
  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 cap height of the font.
  47   virtual int GetCapHeight() const = 0;
  48
  49   // Returns the expected number of horizontal pixels needed to display the
  50   // specified length of characters. Call GetStringWidth() to retrieve the
  51   // actual number.
  52   virtual int GetExpectedTextWidth(int length) const = 0;
  53
  54   // Returns the style of the font.
  55   virtual int GetStyle() const = 0;
  56
  57   // Returns the specified font name in UTF-8.
  58   virtual std::string GetFontName() const = 0;
  59
  60   // Returns the actually used font name in UTF-8.
  61   virtual std::string GetActualFontNameForTesting() const = 0;
  62
  63   // Returns the font size in pixels.
  64   virtual int GetFontSize() const = 0;
  65
  66   // Returns an object describing how the font should be rendered.
  67   virtual const FontRenderParams& GetFontRenderParams() = 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_