ui/views/view_targeter.h

   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
  11 namespace views {
  12
  13 namespace internal {
  14 class RootView;
  15 }  // namespace internal
  16
  17 class View;
  18 class 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|.
  22 class 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_