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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_VIEWS_CONTROLS_LABEL_H_
#define UI_VIEWS_CONTROLS_LABEL_H_
#pragma once
#include <string>
#include "base/compiler_specific.h"
#include "base/gtest_prod_util.h"
#include "base/string16.h"
#include "googleurl/src/gurl.h"
#include "third_party/skia/include/core/SkColor.h"
#include "ui/gfx/font.h"
#include "ui/views/view.h"
namespace views {
/////////////////////////////////////////////////////////////////////////////
//
// Label class
//
// A label is a view subclass that can display a string.
//
/////////////////////////////////////////////////////////////////////////////
class VIEWS_EXPORT Label : public View {
public:
enum Alignment { ALIGN_LEFT = 0,
ALIGN_CENTER,
ALIGN_RIGHT };
// The following enum is used to indicate whether using the Chrome UI's
// directionality as the label's directionality, or auto-detecting the label's
// directionality.
//
// If the label text originates from the Chrome UI, we should use the Chrome
// UI's directionality as the label's directionality.
//
// If the text originates from a web page, its directionality is determined
// based on its first character with strong directionality, disregarding what
// directionality the Chrome UI is.
enum DirectionalityMode {
USE_UI_DIRECTIONALITY = 0,
AUTO_DETECT_DIRECTIONALITY
};
// The view class name.
static const char kViewClassName[];
// The padding for the focus border when rendering focused text.
static const int kFocusBorderPadding;
Label();
explicit Label(const string16& text);
Label(const string16& text, const gfx::Font& font);
virtual ~Label();
// Sets the font.
virtual void SetFont(const gfx::Font& font);
// Sets the label text.
void SetText(const string16& text);
// Sets the label text to |email|. Emails have a custom eliding algorithm.
void SetEmail(const string16& email);
// Sets URL Value - text_ is set to spec().
void SetURL(const GURL& url);
// Returns the font used by this label.
gfx::Font font() const { return font_; }
// Returns the label text.
string16 text() const { return text_; };
// Enables or disables auto-color-readability (enabled by default). If this
// is enabled, then calls to set any foreground or background color will
// trigger an automatic mapper that uses color_utils::GetReadableColor() to
// ensure that the foreground colors are readable over the background color.
void SetAutoColorReadabilityEnabled(bool enabled);
// Sets the color. This will automatically force the color to be readable
// over the current background color.
virtual void SetEnabledColor(const SkColor& color);
void SetDisabledColor(const SkColor& color);
SkColor enabled_color() const { return actual_enabled_color_; }
// Sets the background color. This won't be explicitly drawn, but the label
// will force the text color to be readable over it.
void SetBackgroundColor(const SkColor& color);
// Enables a drop shadow underneath the text.
void SetShadowColors(SkColor enabled_color, SkColor disabled_color);
// Sets the drop shadow's offset from the text.
void SetShadowOffset(int x, int y);
// Disables shadows.
void ClearEmbellishing();
// Sets horizontal alignment. If the locale is RTL, and the directionality
// mode is USE_UI_DIRECTIONALITY, the alignment is flipped around.
//
// Caveat: for labels originating from a web page, the directionality mode
// should be reset to AUTO_DETECT_DIRECTIONALITY before the horizontal
// alignment is set. Otherwise, the label's alignment specified as a parameter
// will be flipped in RTL locales.
void SetHorizontalAlignment(Alignment alignment);
Alignment horizontal_alignment() const { return horiz_alignment_; }
// Sets the directionality mode. The directionality mode is initialized to
// USE_UI_DIRECTIONALITY when the label is constructed. USE_UI_DIRECTIONALITY
// applies to every label that originates from the Chrome UI. However, if the
// label originates from a web page, its directionality is auto-detected.
void set_directionality_mode(DirectionalityMode mode) {
directionality_mode_ = mode;
}
DirectionalityMode directionality_mode() const {
return directionality_mode_;
}
// Sets whether the label text can wrap on multiple lines.
// Default is false.
void SetMultiLine(bool multi_line);
// Returns whether the label text can wrap on multiple lines.
bool is_multi_line() const { return is_multi_line_; }
// Sets whether the label text can be split on words.
// Default is false. This only works when is_multi_line is true.
void SetAllowCharacterBreak(bool allow_character_break);
// Sets whether the label text should be elided in the middle (if necessary).
// The default is to elide at the end.
// NOTE: This is not supported for multi-line strings.
void SetElideInMiddle(bool elide_in_middle);
// Sets the tooltip text. Default behavior for a label (single-line) is to
// show the full text if it is wider than its bounds. Calling this overrides
// the default behavior and lets you set a custom tooltip. To revert to
// default behavior, call this with an empty string.
void SetTooltipText(const string16& tooltip_text);
// The background color to use when the mouse is over the label. Label
// takes ownership of the Background.
void SetMouseOverBackground(Background* background);
const Background* GetMouseOverBackground() const;
// Resizes the label so its width is set to the width of the longest line and
// its height deduced accordingly.
// This is only intended for multi-line labels and is useful when the label's
// text contains several lines separated with \n.
// |max_width| is the maximum width that will be used (longer lines will be
// wrapped). If 0, no maximum width is enforced.
void SizeToFit(int max_width);
// Gets/sets the flag to determine whether the label should be collapsed when
// it's hidden (not visible). If this flag is true, the label will return a
// preferred size of (0, 0) when it's not visible.
void set_collapse_when_hidden(bool value) { collapse_when_hidden_ = value; }
bool collapse_when_hidden() const { return collapse_when_hidden_; }
// Gets/set whether or not this label is to be painted as a focused element.
void set_paint_as_focused(bool paint_as_focused) {
paint_as_focused_ = paint_as_focused;
}
bool paint_as_focused() const { return paint_as_focused_; }
void SetHasFocusBorder(bool has_focus_border);
// Overridden from View:
virtual gfx::Insets GetInsets() const OVERRIDE;
virtual int GetBaseline() const OVERRIDE;
// Overridden to compute the size required to display this label.
virtual gfx::Size GetPreferredSize() OVERRIDE;
// Returns the height necessary to display this label with the provided width.
// This method is used to layout multi-line labels. It is equivalent to
// GetPreferredSize().height() if the receiver is not multi-line.
virtual int GetHeightForWidth(int w) OVERRIDE;
virtual std::string GetClassName() const OVERRIDE;
virtual bool HitTest(const gfx::Point& l) const OVERRIDE;
// Mouse enter/exit are overridden to render mouse over background color.
// These invoke SetContainsMouse as necessary.
virtual void OnMouseMoved(const MouseEvent& event) OVERRIDE;
virtual void OnMouseEntered(const MouseEvent& event) OVERRIDE;
virtual void OnMouseExited(const MouseEvent& event) OVERRIDE;
virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
// Gets the tooltip text for labels that are wider than their bounds, except
// when the label is multiline, in which case it just returns false (no
// tooltip). If a custom tooltip has been specified with SetTooltipText()
// it is returned instead.
virtual bool GetTooltipText(const gfx::Point& p,
string16* tooltip) const OVERRIDE;
protected:
// Called by Paint to paint the text. Override this to change how
// text is painted.
virtual void PaintText(gfx::Canvas* canvas,
const string16& text,
const gfx::Rect& text_bounds,
int flags);
void invalidate_text_size() { text_size_valid_ = false; }
virtual gfx::Size GetTextSize() const;
SkColor disabled_color() const { return actual_disabled_color_; }
// Overridden from View:
// Overridden to dirty our text bounds if we're multi-line.
virtual void OnBoundsChanged(const gfx::Rect& previous_bounds) OVERRIDE;
virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
// If the mouse is over the label, and a mouse over background has been
// specified, its used. Otherwise super's implementation is invoked.
virtual void OnPaintBackground(gfx::Canvas* canvas) OVERRIDE;
private:
// These tests call CalculateDrawStringParams in order to verify the
// calculations done for drawing text.
FRIEND_TEST_ALL_PREFIXES(LabelTest, DrawSingleLineString);
FRIEND_TEST_ALL_PREFIXES(LabelTest, DrawMultiLineString);
FRIEND_TEST_ALL_PREFIXES(LabelTest, DrawSingleLineStringInRTL);
FRIEND_TEST_ALL_PREFIXES(LabelTest, DrawMultiLineStringInRTL);
FRIEND_TEST_ALL_PREFIXES(LabelTest, AutoDetectDirectionality);
// Calls ComputeDrawStringFlags().
FRIEND_TEST_ALL_PREFIXES(LabelTest, DisableSubpixelRendering);
static gfx::Font GetDefaultFont();
void Init(const string16& text, const gfx::Font& font);
void RecalculateColors();
// If the mouse is over the text, SetContainsMouse(true) is invoked, otherwise
// SetContainsMouse(false) is invoked.
void UpdateContainsMouse(const MouseEvent& event);
// Updates whether the mouse is contained in the Label. If the new value
// differs from the current value, and a mouse over background is specified,
// SchedulePaint is invoked.
void SetContainsMouse(bool contains_mouse);
// Returns where the text is drawn, in the receivers coordinate system.
gfx::Rect GetTextBounds() const;
int ComputeDrawStringFlags() const;
gfx::Rect GetAvailableRect() const;
// Returns parameters to be used for the DrawString call.
void CalculateDrawStringParams(string16* paint_text,
gfx::Rect* text_bounds,
int* flags) const;
string16 text_;
GURL url_;
gfx::Font font_;
SkColor requested_enabled_color_;
SkColor actual_enabled_color_;
SkColor requested_disabled_color_;
SkColor actual_disabled_color_;
SkColor background_color_;
bool auto_color_readability_;
mutable gfx::Size text_size_;
mutable bool text_size_valid_;
bool is_multi_line_;
bool allow_character_break_;
bool elide_in_middle_;
bool is_email_;
Alignment horiz_alignment_;
string16 tooltip_text_;
// Whether the mouse is over this label.
bool contains_mouse_;
scoped_ptr<Background> mouse_over_background_;
// Whether to collapse the label when it's not visible.
bool collapse_when_hidden_;
// The following member variable is used to control whether the
// directionality is auto-detected based on first strong directionality
// character or is determined by chrome UI's locale.
DirectionalityMode directionality_mode_;
// When embedded in a larger control that is focusable, setting this flag
// allows this view to be painted as focused even when it is itself not.
bool paint_as_focused_;
// When embedded in a larger control that is focusable, setting this flag
// allows this view to reserve space for a focus border that it otherwise
// might not have because it is not itself focusable.
bool has_focus_border_;
// Colors for shadow.
SkColor enabled_shadow_color_;
SkColor disabled_shadow_color_;
// Space between text and shadow.
gfx::Point shadow_offset_;
// Should a shadow be drawn behind the text?
bool has_shadow_;
DISALLOW_COPY_AND_ASSIGN(Label);
};
} // namespace views
#endif // UI_VIEWS_CONTROLS_LABEL_H_