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      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_BUTTON_MENU_BUTTON_H_
      6 #define UI_VIEWS_CONTROLS_BUTTON_MENU_BUTTON_H_
      7 
      8 #include <string>
      9 
     10 #include "base/memory/weak_ptr.h"
     11 #include "base/strings/string16.h"
     12 #include "base/time/time.h"
     13 #include "ui/views/background.h"
     14 #include "ui/views/controls/button/label_button.h"
     15 
     16 namespace views {
     17 
     18 class MenuButtonListener;
     19 
     20 ////////////////////////////////////////////////////////////////////////////////
     21 //
     22 // MenuButton
     23 //
     24 //  A button that shows a menu when the left mouse button is pushed
     25 //
     26 ////////////////////////////////////////////////////////////////////////////////
     27 class VIEWS_EXPORT MenuButton : public LabelButton {
     28  public:
     29   // A scoped lock for keeping the MenuButton in STATE_PRESSED e.g., while a
     30   // menu is running. These are cumulative.
     31   class VIEWS_EXPORT PressedLock {
     32    public:
     33     explicit PressedLock(MenuButton* menu_button);
     34     ~PressedLock();
     35 
     36    private:
     37     base::WeakPtr<MenuButton> menu_button_;
     38 
     39     DISALLOW_COPY_AND_ASSIGN(PressedLock);
     40   };
     41 
     42   static const char kViewClassName[];
     43 
     44   // How much padding to put on the left and right of the menu marker.
     45   static const int kMenuMarkerPaddingLeft;
     46   static const int kMenuMarkerPaddingRight;
     47 
     48   // Create a Button.
     49   MenuButton(ButtonListener* listener,
     50              const base::string16& text,
     51              MenuButtonListener* menu_button_listener,
     52              bool show_menu_marker);
     53   virtual ~MenuButton();
     54 
     55   bool show_menu_marker() const { return show_menu_marker_; }
     56   void set_menu_marker(const gfx::ImageSkia* menu_marker) {
     57     menu_marker_ = menu_marker;
     58   }
     59   const gfx::ImageSkia* menu_marker() const { return menu_marker_; }
     60 
     61   const gfx::Point& menu_offset() const { return menu_offset_; }
     62   void set_menu_offset(int x, int y) { menu_offset_.SetPoint(x, y); }
     63 
     64   // Activate the button (called when the button is pressed).
     65   virtual bool Activate();
     66 
     67   // Overridden from View:
     68   virtual gfx::Size GetPreferredSize() const OVERRIDE;
     69   virtual const char* GetClassName() const OVERRIDE;
     70   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
     71   virtual bool OnMousePressed(const ui::MouseEvent& event) OVERRIDE;
     72   virtual void OnMouseReleased(const ui::MouseEvent& event) OVERRIDE;
     73   virtual void OnMouseEntered(const ui::MouseEvent& event) OVERRIDE;
     74   virtual void OnMouseExited(const ui::MouseEvent& event) OVERRIDE;
     75   virtual void OnMouseMoved(const ui::MouseEvent& event) OVERRIDE;
     76   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
     77   virtual bool OnKeyPressed(const ui::KeyEvent& event) OVERRIDE;
     78   virtual bool OnKeyReleased(const ui::KeyEvent& event) OVERRIDE;
     79   virtual void GetAccessibleState(ui::AXViewState* state) OVERRIDE;
     80 
     81  protected:
     82   // Paint the menu marker image.
     83   void PaintMenuMarker(gfx::Canvas* canvas);
     84 
     85   // Overridden from LabelButton:
     86   virtual gfx::Rect GetChildAreaBounds() OVERRIDE;
     87 
     88   // Offset of the associated menu position.
     89   gfx::Point menu_offset_;
     90 
     91  private:
     92   friend class PressedLock;
     93 
     94   // Increment/decrement the number of "pressed" locks this button has, and
     95   // set the state accordingly.
     96   void IncrementPressedLocked();
     97   void DecrementPressedLocked();
     98 
     99   // Compute the maximum X coordinate for the current screen. MenuButtons
    100   // use this to make sure a menu is never shown off screen.
    101   int GetMaximumScreenXCoordinate();
    102 
    103   // We use a time object in order to keep track of when the menu was closed.
    104   // The time is used for simulating menu behavior for the menu button; that
    105   // is, if the menu is shown and the button is pressed, we need to close the
    106   // menu. There is no clean way to get the second click event because the
    107   // menu is displayed using a modal loop and, unlike regular menus in Windows,
    108   // the button is not part of the displayed menu.
    109   base::TimeTicks menu_closed_time_;
    110 
    111   // Our listener. Not owned.
    112   MenuButtonListener* listener_;
    113 
    114   // Whether or not we're showing a drop marker.
    115   bool show_menu_marker_;
    116 
    117   // The down arrow used to differentiate the menu button from normal buttons.
    118   const gfx::ImageSkia* menu_marker_;
    119 
    120   // If non-null the destuctor sets this to true. This is set while the menu is
    121   // showing and used to detect if the menu was deleted while running.
    122   bool* destroyed_flag_;
    123 
    124   // The current number of "pressed" locks this button has.
    125   int pressed_lock_count_;
    126 
    127   base::WeakPtrFactory<MenuButton> weak_factory_;
    128 
    129   DISALLOW_COPY_AND_ASSIGN(MenuButton);
    130 };
    131 
    132 }  // namespace views
    133 
    134 #endif  // UI_VIEWS_CONTROLS_BUTTON_MENU_BUTTON_H_
    135