ui/gfx/pango_util.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_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_