ui/views/drag_controller.h

   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,
  34                                        const gfx::Point& p) = 0;
  35
  36   // Returns true if a drag operation can be started.
  37   // |press_pt| represents the coordinates where the mouse was initially
  38   // pressed down. |p| is the current mouse coordinates.
  39   virtual bool CanStartDragForView(View* sender,
  40                                    const gfx::Point& press_pt,
  41                                    const gfx::Point& p) = 0;
  42
  43  protected:
  44   virtual ~DragController() {}
  45 };
  46
  47 }  // namespace views
  48
  49 #endif  // UI_VIEWS_DRAG_CONTROLLER_H_