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 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_IOS)
  25   static PlatformFont* CreateFromNativeFont(NativeFont native_font);
  26 #endif
  27   // Creates a PlatformFont implementation with the specified |font_name|
  28   // (encoded in UTF-8) and |font_size| in pixels.
  29   static PlatformFont* CreateFromNameAndSize(const std::string& font_name,
  30                                              int font_size);
  31
  32   // Returns a new Font derived from the existing font.
  33   // |size_delta| is the size in pixels to add to the current font.
  34   // The style parameter specifies the new style for the font, and is a
  35   // bitmask of the values: BOLD, ITALIC and UNDERLINE.
  36   virtual Font DeriveFont(int size_delta, int style) const = 0;
  37
  38   // Returns the number of vertical pixels needed to display characters from
  39   // the specified font.  This may include some leading, i.e. height may be
  40   // greater than just ascent + descent.  Specifically, the Windows and Mac
  41   // implementations include leading and the Linux one does not.  This may
  42   // need to be revisited in the future.
  43   virtual int GetHeight() const = 0;
  44
  45   // Returns the baseline, or ascent, of the font.
  46   virtual int GetBaseline() const = 0;
  47
  48   // Returns the cap height of the font.
  49   virtual int GetCapHeight() const = 0;
  50
  51   // Returns the expected number of horizontal pixels needed to display the
  52   // specified length of characters. Call GetStringWidth() to retrieve the
  53   // actual number.
  54   virtual int GetExpectedTextWidth(int length) const = 0;
  55
  56   // Returns the style of the font.
  57   virtual int GetStyle() const = 0;
  58
  59   // Returns the specified font name in UTF-8.
  60   virtual std::string GetFontName() const = 0;
  61
  62   // Returns the actually used font name in UTF-8.
  63   virtual std::string GetActualFontNameForTesting() const = 0;
  64
  65   // Returns the font size in pixels.
  66   virtual int GetFontSize() const = 0;
  67
  68   // Returns an object describing how the font should be rendered.
  69   virtual const FontRenderParams& GetFontRenderParams() = 0;
  70
  71 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_IOS)
  72   // Returns the native font handle.
  73   virtual NativeFont GetNativeFont() const = 0;
  74 #endif
  75
  76  protected:
  77   virtual ~PlatformFont() {}
  78
  79  private:
  80   friend class base::RefCounted<PlatformFont>;
  81 };
  82
  83 }  // namespace gfx
  84
  85 #endif  // UI_GFX_PLATFORM_FONT_H_