ui/gfx/font_fallback_win.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_FONT_FALLBACK_WIN_H_
   6 #define UI_GFX_FONT_FALLBACK_WIN_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "ui/gfx/font.h"
  12 #include "ui/gfx/font_fallback.h"
  13
  14 namespace gfx {
  15
  16 // Internals of font_fallback_win.cc exposed for testing.
  17 namespace internal {
  18
  19 // Parses comma separated SystemLink |entry|, per the format described here:
  20 // http://msdn.microsoft.com/en-us/goglobal/bb688134.aspx
  21 //
  22 // Sets |filename| and |font_name| respectively. If a field is not present
  23 // or could not be parsed, the corresponding parameter will be cleared.
  24 void GFX_EXPORT ParseFontLinkEntry(const std::string& entry,
  25                                   std::string* filename,
  26                                   std::string* font_name);
  27
  28 // Parses a font |family| in the format "FamilyFoo & FamilyBar (TrueType)".
  29 // Splits by '&' and strips off the trailing parenthesized expression.
  30 void GFX_EXPORT ParseFontFamilyString(const std::string& family,
  31                                      std::vector<std::string>* font_names);
  32
  33 // Iterator over linked fallback fonts for a given font. The linked font chain
  34 // comes from the Windows registry, but gets cached between uses.
  35 class GFX_EXPORT LinkedFontsIterator {
  36  public:
  37   // Instantiates the iterator over the linked font chain for |font|. The first
  38   // item will be |font| itself.
  39   explicit LinkedFontsIterator(Font font);
  40   virtual ~LinkedFontsIterator();
  41
  42   // Sets the font that would be returned by the next call to |NextFont()|,
  43   // useful for inserting one-time entries into the iterator chain.
  44   void SetNextFont(Font font);
  45
  46   // Gets the next font in the link chain, if available, and increments the
  47   // iterator. Returns |true| on success or |false| if the iterator is past
  48   // last item (in that case, the value of |font| should not be used). If
  49   // |SetNextFont()| was called, returns the font set that way and clears it.
  50   bool NextFont(Font* font);
  51
  52  protected:
  53   // Retrieves the list of linked fonts. Protected and virtual so that it may
  54   // be overridden by tests.
  55   virtual const std::vector<Font>* GetLinkedFonts() const;
  56
  57  private:
  58   // Original font whose linked fonts are being iterated over.
  59   Font original_font_;
  60
  61   // Font that was set via |SetNextFont()|.
  62   Font next_font_;
  63
  64   // Indicates whether |SetNextFont()| was called.
  65   bool next_font_set_;
  66
  67   // The font most recently returned by |NextFont()|.
  68   Font current_font_;
  69
  70   // List of linked fonts; weak pointer.
  71   const std::vector<Font>* linked_fonts_;
  72
  73   // Index of the current entry in the |linked_fonts_| list.
  74   size_t linked_font_index_;
  75
  76   DISALLOW_COPY_AND_ASSIGN(LinkedFontsIterator);
  77 };
  78
  79 }  // namespace internal
  80
  81 // Finds a fallback font to render the specified |text| with respect to an
  82 // initial |font|. Returns the resulting font via out param |result|. Returns
  83 // |true| if a fallback font was found.
  84 bool GetUniscribeFallbackFont(const Font& font,
  85                               const wchar_t* text,
  86                               int text_length,
  87                               Font* result);
  88
  89 }  // namespace gfx
  90
  91 #endif  // UI_GFX_FONT_FALLBACK_WIN_H_