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      1 // Copyright 2014 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 CHROME_BROWSER_UI_VIEWS_PANELS_X11_PANEL_RESIZER_H_
      6 #define CHROME_BROWSER_UI_VIEWS_PANELS_X11_PANEL_RESIZER_H_
      7 
      8 #include "ui/events/event_handler.h"
      9 #include "ui/gfx/point.h"
     10 
     11 namespace aura {
     12 class Window;
     13 }
     14 
     15 class Panel;
     16 
     17 // EventHandler which implements special handling for resizing panels. Panels
     18 // should use X11PanelResizer instead of X11WindowEventFilter.
     19 // When resizing a panel:
     20 // - The panel bounds should update in sync with the user's mouse movement
     21 //   during the resize operation.
     22 // - The layout of all of the panels should be updated once the resize operation
     23 //   completes.
     24 // X11PanelResizer does not hand off resizing to the window manager because it
     25 // is not possible to determine when the window manager has finished resizing.
     26 class X11PanelResizer : public ui::EventHandler {
     27  public:
     28   X11PanelResizer(Panel* panel, aura::Window* window);
     29   virtual ~X11PanelResizer();
     30 
     31  private:
     32   enum ResizeState {
     33     NOT_RESIZING,
     34 
     35     // The user has clicked on one of the panel's edges.
     36     RESIZE_CAN_START,
     37 
     38     // The user has dragged one of the panel's edges far enough for resizing to
     39     // begin.
     40     RESIZE_IN_PROGRESS
     41   };
     42 
     43   // Called as a result of ET_MOUSE_PRESSED.
     44   void OnMousePressed(ui::MouseEvent* event);
     45 
     46   // Called as a result of ET_MOUSE_DRAGGED.
     47   void OnMouseDragged(ui::MouseEvent* event);
     48 
     49   // Stops the resize operation if one is in progress. Consumes |event| if it
     50   // is not NULL and the resize operation was stopped.
     51   void StopResizing(ui::MouseEvent* event, bool canceled);
     52 
     53   // ui::EventHandler:
     54   virtual void OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
     55 
     56   // The panel being resized.
     57   Panel* panel_;
     58 
     59   // |panel|'s window.
     60   aura::Window* window_;
     61 
     62   ResizeState resize_state_;
     63 
     64   // The edge that the user is resizing.
     65   int resize_component_;
     66 
     67   // The location of the mouse click on the window border.
     68   gfx::Point initial_press_location_in_screen_;
     69 
     70   DISALLOW_COPY_AND_ASSIGN(X11PanelResizer);
     71 };
     72 
     73 #endif  // CHROME_BROWSER_UI_VIEWS_PANELS_X11_PANEL_RESIZER_H_
     74