ui/views/controls/styled_label.h

   1 // Copyright 2013 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_VIEWS_CONTROLS_STYLED_LABEL_H_
   6 #define UI_VIEWS_CONTROLS_STYLED_LABEL_H_
   7
   8 #include <list>
   9 #include <map>
  10
  11 #include "base/basictypes.h"
  12 #include "base/strings/string16.h"
  13 #include "third_party/skia/include/core/SkColor.h"
  14 #include "ui/gfx/font_list.h"
  15 #include "ui/gfx/range/range.h"
  16 #include "ui/gfx/size.h"
  17 #include "ui/views/controls/link_listener.h"
  18 #include "ui/views/view.h"
  19
  20 namespace views {
  21
  22 class Link;
  23 class StyledLabelListener;
  24
  25 // A class which can apply mixed styles to a block of text. Currently, text is
  26 // always multiline. Trailing whitespace in the styled label text is not
  27 // supported and will be trimmed on StyledLabel construction. Leading
  28 // whitespace is respected, provided not only whitespace fits in the first line.
  29 // In this case, leading whitespace is ignored.
  30 class VIEWS_EXPORT StyledLabel : public View, public LinkListener {
  31  public:
  32   // Parameters that define label style for a styled label's text range.
  33   struct VIEWS_EXPORT RangeStyleInfo {
  34     RangeStyleInfo();
  35     ~RangeStyleInfo();
  36
  37     // Creates a range style info with default values for link.
  38     static RangeStyleInfo CreateForLink();
  39
  40     // The font style that will be applied to the range. Should be a bitmask of
  41     // values defined in gfx::Font::FontStyle (BOLD, ITALIC, UNDERLINE).
  42     int font_style;
  43
  44     // The text color for the range.
  45     SkColor color;
  46
  47     // Tooltip for the range.
  48     base::string16 tooltip;
  49
  50     // If set, the whole range will be put on a single line.
  51     bool disable_line_wrapping;
  52
  53     // If set, the range will be created as a link.
  54     bool is_link;
  55   };
  56
  57   // Note that any trailing whitespace in |text| will be trimmed.
  58   StyledLabel(const base::string16& text, StyledLabelListener* listener);
  59   virtual ~StyledLabel();
  60
  61   // Sets the text to be displayed, and clears any previous styling.
  62   void SetText(const base::string16& text);
  63
  64   // Sets the fonts used by all labels. Can be augemented by styling set by
  65   // AddStyleRange and SetDefaultStyle.
  66   void SetBaseFontList(const gfx::FontList& font_list);
  67
  68   // Marks the given range within |text_| with style defined by |style_info|.
  69   // |range| must be contained in |text_|.
  70   void AddStyleRange(const gfx::Range& range, const RangeStyleInfo& style_info);
  71
  72   // Sets the default style to use for any part of the text that isn't within
  73   // a range set by AddStyleRange.
  74   void SetDefaultStyle(const RangeStyleInfo& style_info);
  75
  76   // Get or set the distance in pixels between baselines of multi-line text.
  77   // Default is 0, indicating the distance between lines should be the standard
  78   // one for the label's text, font list, and platform.
  79   void SetLineHeight(int height);
  80
  81   // Sets the color of the background on which the label is drawn. This won't
  82   // be explicitly drawn, but the label will force the text color to be
  83   // readable over it.
  84   void SetDisplayedOnBackgroundColor(SkColor color);
  85   SkColor displayed_on_background_color() const {
  86     return displayed_on_background_color_;
  87   }
  88
  89   void set_auto_color_readability_enabled(bool auto_color_readability) {
  90     auto_color_readability_enabled_ = auto_color_readability;
  91   }
  92
  93   // View implementation:
  94   virtual gfx::Insets GetInsets() const OVERRIDE;
  95   virtual int GetHeightForWidth(int w) const OVERRIDE;
  96   virtual void Layout() OVERRIDE;
  97   virtual void PreferredSizeChanged() OVERRIDE;
  98
  99   // LinkListener implementation:
 100   virtual void LinkClicked(Link* source, int event_flags) OVERRIDE;
 101
 102  private:
 103   struct StyleRange {
 104     StyleRange(const gfx::Range& range,
 105                const RangeStyleInfo& style_info)
 106         : range(range),
 107           style_info(style_info) {
 108     }
 109     ~StyleRange() {}
 110
 111     bool operator<(const StyleRange& other) const;
 112
 113     gfx::Range range;
 114     RangeStyleInfo style_info;
 115   };
 116   typedef std::list<StyleRange> StyleRanges;
 117
 118   // Calculates how to layout child views, creates them and sets their size
 119   // and position. |width| is the horizontal space, in pixels, that the view
 120   // has to work with. If |dry_run| is true, the view hierarchy is not touched.
 121   // The return value is the necessary size.
 122   gfx::Size CalculateAndDoLayout(int width, bool dry_run);
 123
 124   // The text to display.
 125   base::string16 text_;
 126
 127   // Fonts used to display text. Can be augmented by RangeStyleInfo.
 128   gfx::FontList font_list_;
 129
 130   // Line height.
 131   int specified_line_height_;
 132
 133   // The default style to use for any part of the text that isn't within
 134   // a range in |style_ranges_|.
 135   RangeStyleInfo default_style_info_;
 136
 137   // The listener that will be informed of link clicks.
 138   StyledLabelListener* listener_;
 139
 140   // The ranges that should be linkified, sorted by start position.
 141   StyleRanges style_ranges_;
 142
 143   // A mapping from a view to the range it corresponds to in |text_|. Only views
 144   // that correspond to ranges with is_link style set will be added to the map.
 145   std::map<View*, gfx::Range> link_targets_;
 146
 147   // This variable saves the result of the last GetHeightForWidth call in order
 148   // to avoid repeated calculation.
 149   mutable gfx::Size calculated_size_;
 150
 151   // Background color on which the label is drawn, for auto color readability.
 152   SkColor displayed_on_background_color_;
 153   bool displayed_on_background_color_set_;
 154
 155   // Controls whether the text is automatically re-colored to be readable on the
 156   // background.
 157   bool auto_color_readability_enabled_;
 158
 159   DISALLOW_COPY_AND_ASSIGN(StyledLabel);
 160 };
 161
 162 }  // namespace views
 163
 164 #endif  // UI_VIEWS_CONTROLS_STYLED_LABEL_H_