1 // Copyright (c) 2011 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_DRAG_CONTROLLER_H_
6 #define UI_VIEWS_DRAG_CONTROLLER_H_
7 
8 #include "ui/views/views_export.h"
9 
10 namespace gfx {
11 class Point;
12 }
13 
14 namespace ui {
15 class OSExchangeData;
16 }
17 
18 namespace views {
19 class View;
20 
21 // DragController is responsible for writing drag data for a view, as well as
22 // supplying the supported drag operations. Use DragController if you don't
23 // want to subclass.
24 class VIEWS_EXPORT DragController {
25  public:
26   // Writes the data for the drag.
27   virtual void WriteDragDataForView(View* sender,
28                                     const gfx::Point& press_pt,
29                                     ui::OSExchangeData* data) = 0;
30 
31   // Returns the supported drag operations (see DragDropTypes for possible
32   // values). A drag is only started if this returns a non-zero value.
33   virtual int GetDragOperationsForView(View* sender, const gfx::Point& p) = 0;
34 
35   // Returns true if a drag operation can be started.
36   // |press_pt| represents the coordinates where the mouse was initially
37   // pressed down. |p| is the current mouse coordinates.
38   virtual bool CanStartDragForView(View* sender,
39                                    const gfx::Point& press_pt,
40                                    const gfx::Point& p) = 0;
41 
42  protected:
43   virtual ~DragController() = default;
44 };
45 
46 }  // namespace views
47 
48 #endif  // UI_VIEWS_DRAG_CONTROLLER_H_
49