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      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_PANGO_UTIL_H_
      6 #define UI_GFX_PANGO_UTIL_H_
      7 
      8 #include <cairo/cairo.h>
      9 #include <pango/pango.h>
     10 #include <string>
     11 
     12 #include "base/i18n/rtl.h"
     13 #include "base/logging.h"
     14 #include "base/strings/string16.h"
     15 #include "third_party/skia/include/core/SkColor.h"
     16 #include "ui/gfx/gfx_export.h"
     17 
     18 typedef struct _PangoContext PangoContext;
     19 
     20 namespace gfx {
     21 
     22 class Font;
     23 class PlatformFontPango;
     24 class Rect;
     25 
     26 // Creates and returns a PangoContext. The caller owns the context.
     27 PangoContext* GetPangoContext();
     28 
     29 // Returns the resolution (DPI) used by pango. A negative values means the
     30 // resolution hasn't been set.
     31 double GetPangoResolution();
     32 
     33 // Utility class to ensure that PangoFontDescription is freed.
     34 class ScopedPangoFontDescription {
     35  public:
     36   explicit ScopedPangoFontDescription(PangoFontDescription* description)
     37       : description_(description) {
     38     DCHECK(description);
     39   }
     40 
     41   ~ScopedPangoFontDescription() {
     42     pango_font_description_free(description_);
     43   }
     44 
     45   PangoFontDescription* get() { return description_; }
     46 
     47  private:
     48   PangoFontDescription* description_;
     49 
     50   DISALLOW_COPY_AND_ASSIGN(ScopedPangoFontDescription);
     51 };
     52 
     53 // ----------------------------------------------------------------------------
     54 // All other methods in this file are only to be used within the ui/ directory.
     55 // They are shared with internal skia interfaces.
     56 // ----------------------------------------------------------------------------
     57 
     58 // Setup pango |layout|; set the |text|, the font description based on
     59 // |font_description|, the |width| in PANGO_SCALE for RTL locale, the base
     60 // |text_direction|, alignment, ellipsis, word wrapping, resolution, etc.
     61 void SetupPangoLayoutWithFontDescription(
     62     PangoLayout* layout,
     63     const base::string16& text,
     64     const std::string& font_description,
     65     int width,
     66     base::i18n::TextDirection text_direction,
     67     int flags);
     68 
     69 // Returns the size in pixels for the specified |pango_font|.
     70 size_t GetPangoFontSizeInPixels(PangoFontDescription* pango_font);
     71 
     72 // Retrieves the Pango metrics for a Pango font description. Caches the metrics
     73 // and never frees them. The metrics objects are relatively small and very
     74 // expensive to look up.
     75 PangoFontMetrics* GetPangoFontMetrics(PangoFontDescription* desc);
     76 
     77 }  // namespace gfx
     78 
     79 #endif  // UI_GFX_PANGO_UTIL_H_
     80