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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 CHROME_BROWSER_UI_GTK_PANELS_PANEL_DRAG_GTK_H_
      6 #define CHROME_BROWSER_UI_GTK_PANELS_PANEL_DRAG_GTK_H_
      7 
      8 #include <gtk/gtk.h>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/compiler_specific.h"
     12 #include "ui/base/gtk/gtk_signal.h"
     13 
     14 class Panel;
     15 class PanelDragDelegate;
     16 
     17 // Class for GTK handling of move-drag and resize-drag on a panel.
     18 // Only one type of drag may be active at any time.
     19 // Dragging only begins if the mouse is moved beyond the drag threshold.
     20 // If mouse is released without exceeding the drag threshold, the mouse
     21 // press and release is treated as a mouse click.
     22 class PanelDragGtk {
     23  public:
     24   explicit PanelDragGtk(Panel* panel);
     25   ~PanelDragGtk();
     26 
     27   GtkWidget* widget() const { return drag_widget_; }
     28 
     29   // Sets up mouse and keyboard events processing while the mouse
     30   // is pressed on a window edge.
     31   // |event| is the mouse press event.
     32   // |cursor| is the cursor to display during the drag.
     33   // |edge| is the window edge from which to resize the panel.
     34   void InitialWindowEdgeMousePress(GdkEventButton* event, GdkCursor* cursor,
     35                                    GdkWindowEdge& edge);
     36 
     37   // Sets up mouse and keyboard events processing while the mouse is
     38   // pressed on the titlebar.
     39   // |event| is the mouse press event.
     40   // |titlebar_widget| should handle the mouse release event if the mouse
     41   // is released without exceeding the drag threshold (a mouse click).
     42   void InitialTitlebarMousePress(GdkEventButton* event,
     43                                  GtkWidget* titlebar_widget);
     44 
     45  private:
     46   friend class GtkNativePanelTesting;
     47 
     48   enum DragState {
     49     NOT_DRAGGING,
     50     DRAG_CAN_START,  // mouse pressed
     51     DRAG_IN_PROGRESS,  // mouse moved beyond drag threshold
     52     DRAG_ENDED_WAITING_FOR_MOUSE_RELEASE
     53   };
     54 
     55   // Callbacks for GTK mouse and key events.
     56   CHROMEGTK_CALLBACK_1(PanelDragGtk, gboolean, OnMouseMoveEvent,
     57                        GdkEventMotion*);
     58   CHROMEGTK_CALLBACK_1(PanelDragGtk, gboolean, OnButtonPressEvent,
     59                        GdkEventButton*);
     60   CHROMEGTK_CALLBACK_1(PanelDragGtk, gboolean, OnButtonReleaseEvent,
     61                        GdkEventButton*);
     62   CHROMEGTK_CALLBACK_1(PanelDragGtk, gboolean, OnKeyPressEvent,
     63                        GdkEventKey*);
     64   CHROMEGTK_CALLBACK_1(PanelDragGtk, gboolean, OnKeyReleaseEvent,
     65                        GdkEventKey*);
     66   CHROMEGTK_CALLBACK_1(PanelDragGtk, gboolean, OnGrabBrokenEvent,
     67                        GdkEventGrabBroken*);
     68 
     69   // Utility to dcheck a bunch of state to ensure a clean slate.
     70   // Returns only if all the dchecks pass.
     71   void AssertCleanState();
     72 
     73   void GrabPointerAndKeyboard(GdkEventButton* event,
     74                               GdkCursor* cursor);
     75   void ReleasePointerAndKeyboardGrab();
     76 
     77   // Ends any drag that is currently in progress (if any).
     78   // Resets all drag state except for pointer and keyboard grabs.
     79   // The grabs are released when the mouse is released to prevent a
     80   // mouse release *after* the drag has ended (e.g. via ESC key) from
     81   // being treated as a mouse click.
     82   void EndDrag(bool canceled);
     83 
     84   // Weak pointer to the panel being dragged.
     85   Panel* panel_;
     86 
     87   // Invisible event box to receive mouse and key events.
     88   GtkWidget* drag_widget_;
     89 
     90   DragState drag_state_;
     91 
     92   // A copy of the initial button press event.
     93   GdkEvent* initial_mouse_down_;
     94 
     95   // Widget that should process the mouse click if mouse is released
     96   // without exceeding the drag threshold. May be NULL if no click
     97   // handling is necessary.
     98   GtkWidget* click_handler_;
     99 
    100   // Delegate for processing drag depends on actual type of drag.
    101   PanelDragDelegate* drag_delegate_;
    102 
    103   DISALLOW_COPY_AND_ASSIGN(PanelDragGtk);
    104 };
    105 
    106 #endif  // CHROME_BROWSER_UI_GTK_PANELS_PANEL_DRAG_GTK_H_
    107