ui/views/controls/label.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_VIEWS_CONTROLS_LABEL_H_
   6 #define UI_VIEWS_CONTROLS_LABEL_H_
   7
   8 #include "base/compiler_specific.h"
   9 #include "base/gtest_prod_util.h"
  10 #include "base/memory/scoped_vector.h"
  11 #include "ui/gfx/render_text.h"
  12 #include "ui/views/view.h"
  13
  14 namespace views {
  15
  16 // A view subclass that can display a string.
  17 class VIEWS_EXPORT Label : public View {
  18  public:
  19   // Internal class name.
  20   static const char kViewClassName[];
  21
  22   // The padding for the focus border when rendering focused text.
  23   static const int kFocusBorderPadding;
  24
  25   Label();
  26   explicit Label(const base::string16& text);
  27   Label(const base::string16& text, const gfx::FontList& font_list);
  28   ~Label() override;
  29
  30   // Gets or sets the fonts used by this label.
  31   const gfx::FontList& font_list() const { return render_text_->font_list(); }
  32
  33   virtual void SetFontList(const gfx::FontList& font_list);
  34
  35   // Get or set the label text.
  36   const base::string16& text() const { return render_text_->text(); }
  37   virtual void SetText(const base::string16& text);
  38
  39   // Enables or disables auto-color-readability (enabled by default).  If this
  40   // is enabled, then calls to set any foreground or background color will
  41   // trigger an automatic mapper that uses color_utils::GetReadableColor() to
  42   // ensure that the foreground colors are readable over the background color.
  43   void SetAutoColorReadabilityEnabled(bool enabled);
  44
  45   // Sets the color.  This will automatically force the color to be readable
  46   // over the current background color, if auto color readability is enabled.
  47   virtual void SetEnabledColor(SkColor color);
  48   void SetDisabledColor(SkColor color);
  49
  50   SkColor enabled_color() const { return actual_enabled_color_; }
  51
  52   // Sets the background color.  This won't be explicitly drawn, but the label
  53   // will force the text color to be readable over it.
  54   void SetBackgroundColor(SkColor color);
  55   SkColor background_color() const { return background_color_; }
  56
  57   // Set drop shadows underneath the text.
  58   void SetShadows(const gfx::ShadowValues& shadows);
  59   const gfx::ShadowValues& shadows() const { return render_text_->shadows(); }
  60
  61   // Sets whether subpixel rendering is used; the default is true, but this
  62   // feature also requires an opaque background color.
  63   // TODO(mukai): rename this as SetSubpixelRenderingSuppressed() to keep the
  64   // consistency with RenderText field name.
  65   void SetSubpixelRenderingEnabled(bool subpixel_rendering_enabled);
  66
  67   // Sets the horizontal alignment; the argument value is mirrored in RTL UI.
  68   void SetHorizontalAlignment(gfx::HorizontalAlignment alignment);
  69   gfx::HorizontalAlignment horizontal_alignment() const {
  70     return render_text_->horizontal_alignment();
  71   }
  72
  73   // Get or set the distance in pixels between baselines of multi-line text.
  74   // Default is 0, indicating the distance between lines should be the standard
  75   // one for the label's text, font list, and platform.
  76   int line_height() const { return render_text_->min_line_height(); }
  77   void SetLineHeight(int height);
  78
  79   // Get or set if the label text can wrap on multiple lines; default is false.
  80   bool multi_line() const { return multi_line_; }
  81   void SetMultiLine(bool multi_line);
  82
  83   // Get or set if the label text should be obscured before rendering (e.g.
  84   // should "Password!" display as "*********"); default is false.
  85   bool obscured() const { return render_text_->obscured(); }
  86   void SetObscured(bool obscured);
  87
  88   // Sets whether multi-line text can wrap mid-word; the default is false.
  89   void SetAllowCharacterBreak(bool allow_character_break);
  90
  91   // Sets the eliding or fading behavior, applied as necessary. The default is
  92   // to elide at the end. Eliding is not well-supported for multi-line labels.
  93   void SetElideBehavior(gfx::ElideBehavior elide_behavior);
  94   gfx::ElideBehavior elide_behavior() const { return elide_behavior_; }
  95
  96   // Sets the tooltip text.  Default behavior for a label (single-line) is to
  97   // show the full text if it is wider than its bounds.  Calling this overrides
  98   // the default behavior and lets you set a custom tooltip.  To revert to
  99   // default behavior, call this with an empty string.
 100   void SetTooltipText(const base::string16& tooltip_text);
 101
 102   // Get or set whether this label can act as a tooltip handler; the default is
 103   // true.  Set to false whenever an ancestor view should handle tooltips
 104   // instead.
 105   bool handles_tooltips() const { return handles_tooltips_; }
 106   void SetHandlesTooltips(bool enabled);
 107
 108   // Resizes the label so its width is set to the width of the longest line and
 109   // its height deduced accordingly.
 110   // This is only intended for multi-line labels and is useful when the label's
 111   // text contains several lines separated with \n.
 112   // |max_width| is the maximum width that will be used (longer lines will be
 113   // wrapped).  If 0, no maximum width is enforced.
 114   void SizeToFit(int max_width);
 115
 116   // Sets whether the preferred size is empty when the label is not visible.
 117   void set_collapse_when_hidden(bool value) { collapse_when_hidden_ = value; }
 118
 119   // Get the text as displayed to the user, respecting the obscured flag.
 120   base::string16 GetDisplayTextForTesting();
 121
 122   // View:
 123   gfx::Insets GetInsets() const override;
 124   int GetBaseline() const override;
 125   gfx::Size GetPreferredSize() const override;
 126   gfx::Size GetMinimumSize() const override;
 127   int GetHeightForWidth(int w) const override;
 128   void Layout() override;
 129   const char* GetClassName() const override;
 130   View* GetTooltipHandlerForPoint(const gfx::Point& point) override;
 131   bool CanProcessEventsWithinSubtree() const override;
 132   void GetAccessibleState(ui::AXViewState* state) override;
 133   bool GetTooltipText(const gfx::Point& p,
 134                       base::string16* tooltip) const override;
 135   void OnEnabledChanged() override;
 136
 137  protected:
 138   void PaintText(gfx::Canvas* canvas);
 139
 140   SkColor disabled_color() const { return actual_disabled_color_; }
 141
 142   // View:
 143   void OnBoundsChanged(const gfx::Rect& previous_bounds) override;
 144   void VisibilityChanged(View* starting_from, bool is_visible) override;
 145   void OnPaint(gfx::Canvas* canvas) override;
 146   void OnDeviceScaleFactorChanged(float device_scale_factor) override;
 147   void OnNativeThemeChanged(const ui::NativeTheme* theme) override;
 148
 149  private:
 150   FRIEND_TEST_ALL_PREFIXES(LabelTest, ResetRenderTextData);
 151   FRIEND_TEST_ALL_PREFIXES(LabelTest, MultilineSupportedRenderText);
 152   FRIEND_TEST_ALL_PREFIXES(LabelTest, TextChangeWithoutLayout);
 153   FRIEND_TEST_ALL_PREFIXES(LabelFocusTest, FocusBounds);
 154   FRIEND_TEST_ALL_PREFIXES(LabelFocusTest, EmptyLabel);
 155
 156   void Init(const base::string16& text, const gfx::FontList& font_list);
 157
 158   void ResetLayout();
 159
 160   // Create a single RenderText instance to actually be painted.
 161   scoped_ptr<gfx::RenderText> CreateRenderText(
 162       const base::string16& text,
 163       gfx::HorizontalAlignment alignment,
 164       gfx::DirectionalityMode directionality,
 165       gfx::ElideBehavior elide_behavior);
 166
 167   // Set up |lines_| to actually be painted.
 168   void MaybeBuildRenderTextLines();
 169
 170   gfx::Rect GetFocusBounds();
 171
 172   // Get the text broken into lines as needed to fit the given |width|.
 173   std::vector<base::string16> GetLinesForWidth(int width) const;
 174
 175   // Get the text size for the current layout.
 176   gfx::Size GetTextSize() const;
 177
 178   void RecalculateColors();
 179
 180   // Updates any colors that have not been explicitly set from the theme.
 181   void UpdateColorsFromTheme(const ui::NativeTheme* theme);
 182
 183   bool ShouldShowDefaultTooltip() const;
 184
 185   // An un-elided and single-line RenderText object used for preferred sizing.
 186   scoped_ptr<gfx::RenderText> render_text_;
 187
 188   // The RenderText instances used to display elided and multi-line text.
 189   ScopedVector<gfx::RenderText> lines_;
 190
 191   SkColor requested_enabled_color_;
 192   SkColor actual_enabled_color_;
 193   SkColor requested_disabled_color_;
 194   SkColor actual_disabled_color_;
 195   SkColor background_color_;
 196
 197   // Set to true once the corresponding setter is invoked.
 198   bool enabled_color_set_;
 199   bool disabled_color_set_;
 200   bool background_color_set_;
 201
 202   gfx::ElideBehavior elide_behavior_;
 203
 204   bool subpixel_rendering_enabled_;
 205   bool auto_color_readability_;
 206   // TODO(mukai): remove |multi_line_| when all RenderText can render multiline.
 207   bool multi_line_;
 208   base::string16 tooltip_text_;
 209   bool handles_tooltips_;
 210   // Whether to collapse the label when it's not visible.
 211   bool collapse_when_hidden_;
 212   bool allow_character_break_;
 213   int max_width_;
 214
 215   // TODO(vadimt): Remove is_first_paint_text_ before crbug.com/431326 is
 216   // closed.
 217   bool is_first_paint_text_;
 218
 219   DISALLOW_COPY_AND_ASSIGN(Label);
 220 };
 221
 222 }  // namespace views
 223
 224 #endif  // UI_VIEWS_CONTROLS_LABEL_H_