view_targeter.h revision 1320f92c476a1ad9d19dba2a48c72b75566198e9 
1// Copyright 2014 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_VIEW_TARGETER_H_
6#define UI_VIEWS_VIEW_TARGETER_H_
7
8#include "ui/events/event_targeter.h"
9#include "ui/views/views_export.h"
10
11namespace views {
12
13namespace internal {
14class RootView;
15}  // namespace internal
16
17class View;
18class ViewTargeterDelegate;
19
20// A ViewTargeter is installed on a View that wishes to use the custom
21// hit-testing or event-targeting behaviour defined by |delegate|.
22class VIEWS_EXPORT ViewTargeter : public ui::EventTargeter {
23 public:
24  explicit ViewTargeter(ViewTargeterDelegate* delegate);
25  virtual ~ViewTargeter();
26
27  // A call-through to DoesIntersectRect() on |delegate_|.
28  bool DoesIntersectRect(const View* target, const gfx::Rect& rect) const;
29
30  // A call-through to TargetForRect() on |delegate_|.
31  View* TargetForRect(View* root, const gfx::Rect& rect) const;
32
33 protected:
34  // ui::EventTargeter:
35  virtual ui::EventTarget* FindTargetForEvent(ui::EventTarget* root,
36                                              ui::Event* event) OVERRIDE;
37  virtual ui::EventTarget* FindNextBestTarget(ui::EventTarget* previous_target,
38                                              ui::Event* event) OVERRIDE;
39  virtual bool SubtreeCanAcceptEvent(
40      ui::EventTarget* target,
41      const ui::LocatedEvent& event) const OVERRIDE;
42  virtual bool EventLocationInsideBounds(
43      ui::EventTarget* target,
44      const ui::LocatedEvent& event) const OVERRIDE;
45
46 private:
47  // TODO(tdanderson): Un-friend RootView once RootView::DispatchGestureEvent()
48  //                   has been removed.
49  friend class internal::RootView;
50
51  View* FindTargetForKeyEvent(View* root, const ui::KeyEvent& key);
52  View* FindTargetForScrollEvent(View* root, const ui::ScrollEvent& scroll);
53
54  virtual View* FindTargetForGestureEvent(View* root,
55                                          const ui::GestureEvent& gesture);
56  virtual ui::EventTarget* FindNextBestTargetForGestureEvent(
57      ui::EventTarget* previous_target,
58      const ui::GestureEvent& gesture);
59
60  // ViewTargeter does not own the |delegate_|, but |delegate_| must
61  // outlive the targeter.
62  ViewTargeterDelegate* delegate_;
63
64  DISALLOW_COPY_AND_ASSIGN(ViewTargeter);
65};
66
67}  // namespace views
68
69#endif  // UI_VIEWS_VIEW_TARGETER_H_
70