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.
5 #ifndef UI_VIEWS_CONTROLS_LABEL_H_
6 #define UI_VIEWS_CONTROLS_LABEL_H_
11 #include "base/compiler_specific.h"
12 #include "base/gtest_prod_util.h"
13 #include "base/strings/string16.h"
14 #include "third_party/skia/include/core/SkColor.h"
15 #include "ui/gfx/font_list.h"
16 #include "ui/gfx/text_constants.h"
17 #include "ui/views/view.h"
21 /////////////////////////////////////////////////////////////////////////////
25 // A label is a view subclass that can display a string.
27 /////////////////////////////////////////////////////////////////////////////
28 class VIEWS_EXPORT Label : public View {
30 // Internal class name.
31 static const char kViewClassName[];
33 // The following enum is used to indicate whether using the Chrome UI's
34 // directionality as the label's directionality, or auto-detecting the label's
37 // If the label text originates from the Chrome UI, we should use the Chrome
38 // UI's directionality as the label's directionality.
40 // If the text originates from a web page, its directionality is determined
41 // based on its first character with strong directionality, disregarding what
42 // directionality the Chrome UI is.
43 enum DirectionalityMode {
44 USE_UI_DIRECTIONALITY = 0,
45 AUTO_DETECT_DIRECTIONALITY
49 NO_ELIDE, // Do not elide the label text; truncate as needed.
50 ELIDE_IN_MIDDLE, // Add ellipsis in the middle of the string as needed.
51 ELIDE_AT_END, // Add ellipsis at the end of the string as needed.
52 ELIDE_AS_EMAIL, // Elide while retaining username/domain chars as needed.
56 explicit Label(const string16& text);
57 Label(const string16& text, const gfx::FontList& font_list);
58 Label(const string16& text, const gfx::Font& font); // OBSOLETE
61 // Gets or sets the fonts used by this label.
62 const gfx::FontList& font_list() const { return font_list_; }
63 virtual void SetFontList(const gfx::FontList& font_list);
64 // Obsolete gfx::Font version. Should use gfx::FontList version instead.
65 const gfx::Font& font() const; // OBSOLETE
66 virtual void SetFont(const gfx::Font& font); // OBSOLETE
68 // Get or set the label text.
69 const string16& text() const { return text_; }
70 void SetText(const string16& text);
72 // Enables or disables auto-color-readability (enabled by default). If this
73 // is enabled, then calls to set any foreground or background color will
74 // trigger an automatic mapper that uses color_utils::GetReadableColor() to
75 // ensure that the foreground colors are readable over the background color.
76 void SetAutoColorReadabilityEnabled(bool enabled);
78 // Sets the color. This will automatically force the color to be readable
79 // over the current background color.
80 virtual void SetEnabledColor(SkColor color);
81 void SetDisabledColor(SkColor color);
83 SkColor enabled_color() const { return actual_enabled_color_; }
85 // Sets the background color. This won't be explicitly drawn, but the label
86 // will force the text color to be readable over it.
87 void SetBackgroundColor(SkColor color);
88 SkColor background_color() const { return background_color_; }
90 // Enables a drop shadow underneath the text.
91 void SetShadowColors(SkColor enabled_color, SkColor disabled_color);
93 // Sets the drop shadow's offset from the text.
94 void SetShadowOffset(int x, int y);
97 void ClearEmbellishing();
99 // Sets horizontal alignment. If the locale is RTL, and the directionality
100 // mode is USE_UI_DIRECTIONALITY, the alignment is flipped around.
102 // Caveat: for labels originating from a web page, the directionality mode
103 // should be reset to AUTO_DETECT_DIRECTIONALITY before the horizontal
104 // alignment is set. Otherwise, the label's alignment specified as a parameter
105 // will be flipped in RTL locales.
106 void SetHorizontalAlignment(gfx::HorizontalAlignment alignment);
108 gfx::HorizontalAlignment horizontal_alignment() const {
109 return horizontal_alignment_;
112 // Sets the directionality mode. The directionality mode is initialized to
113 // USE_UI_DIRECTIONALITY when the label is constructed. USE_UI_DIRECTIONALITY
114 // applies to every label that originates from the Chrome UI. However, if the
115 // label originates from a web page, its directionality is auto-detected.
116 void set_directionality_mode(DirectionalityMode mode) {
117 directionality_mode_ = mode;
120 DirectionalityMode directionality_mode() const {
121 return directionality_mode_;
124 // Get or set the distance in pixels between baselines of multi-line text.
125 // Default is 0, indicating the distance between lines should be the standard
126 // one for the label's text, font list, and platform.
127 int line_height() const { return line_height_; }
128 void SetLineHeight(int height);
130 // Get or set if the label text can wrap on multiple lines; default is false.
131 bool is_multi_line() const { return is_multi_line_; }
132 void SetMultiLine(bool multi_line);
134 // Sets whether the label text can be split on words.
135 // Default is false. This only works when is_multi_line is true.
136 void SetAllowCharacterBreak(bool allow_character_break);
138 // Sets whether the label text should be elided in the middle or end (if
139 // necessary). The default is to elide at the end.
140 // NOTE: Eliding in the middle is not supported for multi-line strings.
141 void SetElideBehavior(ElideBehavior elide_behavior);
143 // Sets the tooltip text. Default behavior for a label (single-line) is to
144 // show the full text if it is wider than its bounds. Calling this overrides
145 // the default behavior and lets you set a custom tooltip. To revert to
146 // default behavior, call this with an empty string.
147 void SetTooltipText(const string16& tooltip_text);
149 // Resizes the label so its width is set to the width of the longest line and
150 // its height deduced accordingly.
151 // This is only intended for multi-line labels and is useful when the label's
152 // text contains several lines separated with \n.
153 // |max_width| is the maximum width that will be used (longer lines will be
154 // wrapped). If 0, no maximum width is enforced.
155 void SizeToFit(int max_width);
157 // Gets/sets the flag to determine whether the label should be collapsed when
158 // it's hidden (not visible). If this flag is true, the label will return a
159 // preferred size of (0, 0) when it's not visible.
160 void set_collapse_when_hidden(bool value) { collapse_when_hidden_ = value; }
161 bool collapse_when_hidden() const { return collapse_when_hidden_; }
163 void SetHasFocusBorder(bool has_focus_border);
165 // Overridden from View:
166 virtual gfx::Insets GetInsets() const OVERRIDE;
167 virtual int GetBaseline() const OVERRIDE;
168 // Overridden to compute the size required to display this label.
169 virtual gfx::Size GetPreferredSize() OVERRIDE;
170 // Returns the height necessary to display this label with the provided width.
171 // This method is used to layout multi-line labels. It is equivalent to
172 // GetPreferredSize().height() if the receiver is not multi-line.
173 virtual int GetHeightForWidth(int w) OVERRIDE;
174 virtual const char* GetClassName() const OVERRIDE;
175 virtual View* GetTooltipHandlerForPoint(const gfx::Point& point) OVERRIDE;
176 virtual bool HitTestRect(const gfx::Rect& rect) const OVERRIDE;
177 virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
178 // Gets the tooltip text for labels that are wider than their bounds, except
179 // when the label is multiline, in which case it just returns false (no
180 // tooltip). If a custom tooltip has been specified with SetTooltipText()
181 // it is returned instead.
182 virtual bool GetTooltipText(const gfx::Point& p,
183 string16* tooltip) const OVERRIDE;
186 // Called by Paint to paint the text. Override this to change how
188 virtual void PaintText(gfx::Canvas* canvas,
189 const string16& text,
190 const gfx::Rect& text_bounds,
193 virtual gfx::Size GetTextSize() const;
195 SkColor disabled_color() const { return actual_disabled_color_; }
197 // Overridden from View:
198 // Overridden to dirty our text bounds if we're multi-line.
199 virtual void OnBoundsChanged(const gfx::Rect& previous_bounds) OVERRIDE;
200 virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
201 virtual void OnNativeThemeChanged(const ui::NativeTheme* theme) OVERRIDE;
204 // These tests call CalculateDrawStringParams in order to verify the
205 // calculations done for drawing text.
206 FRIEND_TEST_ALL_PREFIXES(LabelTest, DrawSingleLineString);
207 FRIEND_TEST_ALL_PREFIXES(LabelTest, DrawMultiLineString);
208 FRIEND_TEST_ALL_PREFIXES(LabelTest, DrawSingleLineStringInRTL);
209 FRIEND_TEST_ALL_PREFIXES(LabelTest, DrawMultiLineStringInRTL);
210 FRIEND_TEST_ALL_PREFIXES(LabelTest, AutoDetectDirectionality);
212 // Calls ComputeDrawStringFlags().
213 FRIEND_TEST_ALL_PREFIXES(LabelTest, DisableSubpixelRendering);
215 void Init(const string16& text, const gfx::FontList& font_list);
217 void RecalculateColors();
219 // Returns where the text is drawn, in the receivers coordinate system.
220 gfx::Rect GetTextBounds() const;
222 int ComputeDrawStringFlags() const;
224 gfx::Rect GetAvailableRect() const;
226 // Returns parameters to be used for the DrawString call.
227 void CalculateDrawStringParams(string16* paint_text,
228 gfx::Rect* text_bounds,
231 // Updates any colors that have not been explicitly set from the theme.
232 void UpdateColorsFromTheme(const ui::NativeTheme* theme);
234 // Resets |cached_heights_| and |cached_heights_cursor_| and mark
235 // |text_size_valid_| as false.
236 void ResetCachedSize();
238 bool ShouldShowDefaultTooltip() const;
241 gfx::FontList font_list_;
242 SkColor requested_enabled_color_;
243 SkColor actual_enabled_color_;
244 SkColor requested_disabled_color_;
245 SkColor actual_disabled_color_;
246 SkColor background_color_;
248 // Set to true once the corresponding setter is invoked.
249 bool enabled_color_set_;
250 bool disabled_color_set_;
251 bool background_color_set_;
253 bool auto_color_readability_;
254 mutable gfx::Size text_size_;
255 mutable bool text_size_valid_;
258 bool allow_character_break_;
259 ElideBehavior elide_behavior_;
260 gfx::HorizontalAlignment horizontal_alignment_;
261 string16 tooltip_text_;
262 // Whether to collapse the label when it's not visible.
263 bool collapse_when_hidden_;
264 // The following member variable is used to control whether the
265 // directionality is auto-detected based on first strong directionality
266 // character or is determined by chrome UI's locale.
267 DirectionalityMode directionality_mode_;
268 // When embedded in a larger control that is focusable, setting this flag
269 // allows this view to reserve space for a focus border that it otherwise
270 // might not have because it is not itself focusable.
271 bool has_focus_border_;
273 // Colors for shadow.
274 SkColor enabled_shadow_color_;
275 SkColor disabled_shadow_color_;
277 // Space between text and shadow.
278 gfx::Point shadow_offset_;
280 // Should a shadow be drawn behind the text?
283 // The cached heights to avoid recalculation in GetHeightForWidth().
284 std::vector<gfx::Size> cached_heights_;
285 int cached_heights_cursor_;
287 DISALLOW_COPY_AND_ASSIGN(Label);
292 #endif // UI_VIEWS_CONTROLS_LABEL_H_