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 class View;
  14 class ViewTargeterDelegate;
  15
  16 // Contains the logic used to determine the View to which an
  17 // event should be dispatched. A ViewTargeter (or one of its
  18 // derived classes) is installed on a View to specify the
  19 // targeting behaviour to be used for the subtree rooted at
  20 // that View.
  21 // TODO(tdanderson): Remove overrides of all EventHandler methods except for
  22 //                   FindTargetForEvent() and FindNextBestTarget().
  23 class VIEWS_EXPORT ViewTargeter : public ui::EventTargeter {
  24  public:
  25   explicit ViewTargeter(ViewTargeterDelegate* delegate);
  26   virtual ~ViewTargeter();
  27
  28   // A call-through to DoesIntersectRect() on |delegate_|.
  29   bool DoesIntersectRect(const View* target, const gfx::Rect& rect) const;
  30
  31   // A call-through to TargetForRect() on |delegate_|.
  32   View* TargetForRect(View* root, const gfx::Rect& rect) const;
  33
  34  protected:
  35   // Returns the location of |event| represented as a rect. If |event| is
  36   // a gesture event, its bounding box is returned. Otherwise, a 1x1 rect
  37   // having its origin at the location of |event| is returned.
  38   gfx::RectF BoundsForEvent(const ui::LocatedEvent& event) const;
  39
  40   // ui::EventTargeter:
  41   virtual ui::EventTarget* FindTargetForEvent(ui::EventTarget* root,
  42                                               ui::Event* event) OVERRIDE;
  43   virtual ui::EventTarget* FindNextBestTarget(ui::EventTarget* previous_target,
  44                                               ui::Event* event) OVERRIDE;
  45   virtual bool SubtreeCanAcceptEvent(
  46       ui::EventTarget* target,
  47       const ui::LocatedEvent& event) const OVERRIDE;
  48   virtual bool EventLocationInsideBounds(
  49       ui::EventTarget* target,
  50       const ui::LocatedEvent& event) const OVERRIDE;
  51
  52  private:
  53   View* FindTargetForKeyEvent(View* view, const ui::KeyEvent& key);
  54
  55   // ViewTargeter does not own the |delegate_|, but |delegate_| must
  56   // outlive the targeter.
  57   ViewTargeterDelegate* delegate_;
  58
  59   DISALLOW_COPY_AND_ASSIGN(ViewTargeter);
  60 };
  61
  62 }  // namespace views
  63
  64 #endif  // UI_VIEWS_VIEW_TARGETER_H_