ui/aura/window_targeter.h

   1 // Copyright (c) 2013 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_AURA_WINDOW_TARGETER_H_
   6 #define UI_AURA_WINDOW_TARGETER_H_
   7
   8 #include "base/macros.h"
   9 #include "ui/aura/aura_export.h"
  10 #include "ui/events/event_targeter.h"
  11
  12 namespace ui {
  13 class KeyEvent;
  14 class LocatedEvent;
  15 }  // namespace ui
  16
  17 namespace aura {
  18
  19 class Window;
  20
  21 class AURA_EXPORT WindowTargeter : public ui::EventTargeter {
  22  public:
  23   WindowTargeter();
  24   ~WindowTargeter() override;
  25
  26   // Returns true if |window| or one of its descendants can be a target of
  27   // |event|. This requires that |window| and its descendants are not
  28   // prohibited from accepting the event, and that the event is within an
  29   // actionable region of the target's bounds. Note that the location etc. of
  30   // |event| is in |window|'s parent's coordinate system.
  31   virtual bool SubtreeShouldBeExploredForEvent(Window* window,
  32                                                const ui::LocatedEvent& event);
  33
  34  protected:
  35   // Same as FindTargetForEvent(), but used for positional events. The location
  36   // etc. of |event| are in |root|'s coordinate system. When finding the target
  37   // for the event, the targeter can mutate the |event| (e.g. change the
  38   // coordinate to be in the returned target's coordinate system) so that it can
  39   // be dispatched to the target without any further modification.
  40   virtual Window* FindTargetForLocatedEvent(Window* window,
  41                                             ui::LocatedEvent* event);
  42
  43   // Returns false if neither |window| nor any of its descendants are allowed
  44   // to accept |event| for reasons unrelated to the event's location or the
  45   // target's bounds. For example, overrides of this function may consider
  46   // attributes such as the visibility or enabledness of |window|. Note that
  47   // the location etc. of |event| is in |window|'s parent's coordinate system.
  48   virtual bool SubtreeCanAcceptEvent(Window* window,
  49                                      const ui::LocatedEvent& event) const;
  50
  51   // Returns whether the location of the event is in an actionable region of the
  52   // target. Note that the location etc. of |event| is in the |window|'s
  53   // parent's coordinate system.
  54   virtual bool EventLocationInsideBounds(Window* target,
  55                                          const ui::LocatedEvent& event) const;
  56
  57   // ui::EventTargeter:
  58   ui::EventTarget* FindTargetForEvent(ui::EventTarget* root,
  59                                       ui::Event* event) override;
  60   ui::EventTarget* FindNextBestTarget(ui::EventTarget* previous_target,
  61                                       ui::Event* event) override;
  62
  63  private:
  64   Window* FindTargetForKeyEvent(Window* root_window, const ui::KeyEvent& event);
  65   Window* FindTargetForNonKeyEvent(Window* root_window, ui::Event* event);
  66   Window* FindTargetInRootWindow(Window* root_window,
  67                                  const ui::LocatedEvent& event);
  68   Window* FindTargetForLocatedEventRecursively(Window* root_window,
  69                                                ui::LocatedEvent* event);
  70
  71   DISALLOW_COPY_AND_ASSIGN(WindowTargeter);
  72 };
  73
  74 }  // namespace aura
  75
  76 #endif  // UI_AURA_WINDOW_TARGETER_H_