ui/touch_selection/touch_selection_draggable.h

   1 // Copyright 2015 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_TOUCH_SELECTION_DRAG_DRAGGABLE_H_
   6 #define UI_TOUCH_SELECTION_DRAG_DRAGGABLE_H_
   7
   8 #include "ui/gfx/geometry/point_f.h"
   9 #include "ui/touch_selection/ui_touch_selection_export.h"
  10
  11 namespace ui {
  12
  13 class MotionEvent;
  14 class TouchSelectionDraggable;
  15
  16 // Interface through which TouchSelectionDraggable manipulates the selection.
  17 class UI_TOUCH_SELECTION_EXPORT TouchSelectionDraggableClient {
  18  public:
  19   virtual ~TouchSelectionDraggableClient() {}
  20   virtual void OnDragBegin(const TouchSelectionDraggable& draggable,
  21                            const gfx::PointF& start_position) = 0;
  22   virtual void OnDragUpdate(const TouchSelectionDraggable& draggable,
  23                             const gfx::PointF& new_position) = 0;
  24   virtual void OnDragEnd(const TouchSelectionDraggable& draggable) = 0;
  25   virtual bool IsWithinTapSlop(const gfx::Vector2dF& delta) const = 0;
  26 };
  27
  28 // Generic interface for entities that manipulate the selection via dragging.
  29 class UI_TOUCH_SELECTION_EXPORT TouchSelectionDraggable {
  30  protected:
  31   virtual ~TouchSelectionDraggable() {}
  32
  33   // Offers a touch sequence to the draggable target. Returns true if the event
  34   // was consumed, in which case the caller should cease further handling.
  35   virtual bool WillHandleTouchEvent(const ui::MotionEvent& event) = 0;
  36
  37   // Whether a drag is active OR being detected for the current touch sequence.
  38   virtual bool IsActive() const = 0;
  39 };
  40
  41 }  // namespace ui
  42
  43 #endif  // UI_TOUCH_SELECTION_DRAG_DRAGGABLE_H_