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   ~ViewTargeter() override;
  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   ui::EventTarget* FindTargetForEvent(ui::EventTarget* root,
  36                                       ui::Event* event) override;
  37   ui::EventTarget* FindNextBestTarget(ui::EventTarget* previous_target,
  38                                       ui::Event* event) override;
  39   bool SubtreeCanAcceptEvent(ui::EventTarget* target,
  40                              const ui::LocatedEvent& event) const override;
  41   bool EventLocationInsideBounds(ui::EventTarget* target,
  42                                  const ui::LocatedEvent& event) const override;
  43
  44  private:
  45   // TODO(tdanderson): Un-friend RootView once RootView::DispatchGestureEvent()
  46   //                   has been removed.
  47   friend class internal::RootView;
  48
  49   View* FindTargetForKeyEvent(View* root, const ui::KeyEvent& key);
  50   View* FindTargetForScrollEvent(View* root, const ui::ScrollEvent& scroll);
  51
  52   virtual View* FindTargetForGestureEvent(View* root,
  53                                           const ui::GestureEvent& gesture);
  54   virtual ui::EventTarget* FindNextBestTargetForGestureEvent(
  55       ui::EventTarget* previous_target,
  56       const ui::GestureEvent& gesture);
  57
  58   // ViewTargeter does not own the |delegate_|, but |delegate_| must
  59   // outlive the targeter.
  60   ViewTargeterDelegate* delegate_;
  61
  62   DISALLOW_COPY_AND_ASSIGN(ViewTargeter);
  63 };
  64
  65 }  // namespace views
  66
  67 #endif  // UI_VIEWS_VIEW_TARGETER_H_