ash/drag_drop/drag_image_view.h

   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 ASH_DRAG_DROP_DRAG_IMAGE_VIEW_H_
   6 #define ASH_DRAG_DROP_DRAG_IMAGE_VIEW_H_
   7
   8 #include "ui/base/dragdrop/drag_drop_types.h"
   9 #include "ui/views/controls/image_view.h"
  10
  11 namespace views {
  12 class Widget;
  13 }
  14
  15 namespace ash {
  16
  17 // This class allows to show a (native) view always on top of everything. It
  18 // does this by creating a widget and setting the content as the given view. The
  19 // caller can then use this object to freely move / drag it around on the
  20 // desktop in screen coordinates.
  21 class DragImageView : public views::ImageView {
  22  public:
  23   // |context is the native view context used to create the widget holding the
  24   // drag image.
  25   // |source| is the event source that started this drag drop operation (touch
  26   // or mouse). It is used to determine attributes of the drag image such as
  27   // whether to show drag operation hint on top of the image.
  28   DragImageView(gfx::NativeView context,
  29                 ui::DragDropTypes::DragEventSource source);
  30   ~DragImageView() override;
  31
  32   // Sets the bounds of the native widget in screen
  33   // coordinates.
  34   // TODO(oshima): Looks like this is root window's
  35   // coordinate. Change this to screen's coordinate.
  36   void SetBoundsInScreen(const gfx::Rect& bounds);
  37
  38   // Sets the position of the native widget.
  39   void SetScreenPosition(const gfx::Point& position);
  40
  41   // Gets the image position in screen coordinates.
  42   gfx::Rect GetBoundsInScreen() const;
  43
  44   // Sets the visibility of the native widget.
  45   void SetWidgetVisible(bool visible);
  46
  47   // For touch drag drop, we show a hint corresponding to the drag operation
  48   // (since no mouse cursor is visible). These functions set the hint
  49   // parameters.
  50   void SetTouchDragOperationHintOff();
  51
  52   // |operation| is a bit field indicating allowable drag operations from
  53   // ui::DragDropTypes::DragOperation.
  54   void SetTouchDragOperation(int operation);
  55   void SetTouchDragOperationHintPosition(const gfx::Point& position);
  56
  57   // Sets the |opacity| of the image view between 0.0 and 1.0.
  58   void SetOpacity(float opacity);
  59
  60  private:
  61   // Overridden from views::ImageView.
  62   void OnPaint(gfx::Canvas* canvas) override;
  63
  64   scoped_ptr<views::Widget> widget_;
  65   gfx::Size widget_size_;
  66
  67   ui::DragDropTypes::DragEventSource drag_event_source_;
  68   int touch_drag_operation_;
  69   gfx::Point touch_drag_operation_indicator_position_;
  70
  71   DISALLOW_COPY_AND_ASSIGN(DragImageView);
  72 };
  73
  74 }  // namespace ash
  75
  76 #endif  // ASH_DRAG_DROP_DRAG_IMAGE_VIEW_H_