ui/events/event_targeter.cc

   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 #include "ui/events/event_targeter.h"
   6
   7 #include "ui/events/event.h"
   8 #include "ui/events/event_target.h"
   9 #include "ui/events/event_target_iterator.h"
  10
  11 namespace ui {
  12
  13 EventTargeter::~EventTargeter() {
  14 }
  15
  16 EventTarget* EventTargeter::FindTargetForEvent(EventTarget* root,
  17                                                Event* event) {
  18   if (event->IsMouseEvent() ||
  19       event->IsScrollEvent() ||
  20       event->IsTouchEvent() ||
  21       event->IsGestureEvent()) {
  22     return FindTargetForLocatedEvent(root,
  23                                      static_cast<LocatedEvent*>(event));
  24   }
  25   return root;
  26 }
  27
  28 EventTarget* EventTargeter::FindTargetForLocatedEvent(EventTarget* root,
  29                                                       LocatedEvent* event) {
  30   scoped_ptr<EventTargetIterator> iter = root->GetChildIterator();
  31   if (iter) {
  32     EventTarget* target = root;
  33     for (EventTarget* child = iter->GetNextTarget(); child;
  34          child = iter->GetNextTarget()) {
  35       EventTargeter* targeter = child->GetEventTargeter();
  36       if (!targeter)
  37         targeter = this;
  38       if (!targeter->SubtreeShouldBeExploredForEvent(child, *event))
  39         continue;
  40       target->ConvertEventToTarget(child, event);
  41       target = child;
  42       EventTarget* child_target = targeter ?
  43           targeter->FindTargetForLocatedEvent(child, event) :
  44           FindTargetForLocatedEvent(child, event);
  45       if (child_target)
  46         return child_target;
  47     }
  48     target->ConvertEventToTarget(root, event);
  49   }
  50   return root->CanAcceptEvent(*event) ? root : NULL;
  51 }
  52
  53 bool EventTargeter::SubtreeShouldBeExploredForEvent(EventTarget* target,
  54                                                     const LocatedEvent& event) {
  55   return SubtreeCanAcceptEvent(target, event) &&
  56          EventLocationInsideBounds(target, event);
  57 }
  58
  59 EventTarget* EventTargeter::FindNextBestTarget(EventTarget* previous_target,
  60                                                Event* event) {
  61   return NULL;
  62 }
  63
  64 bool EventTargeter::SubtreeCanAcceptEvent(EventTarget* target,
  65                                           const LocatedEvent& event) const {
  66   return true;
  67 }
  68
  69 bool EventTargeter::EventLocationInsideBounds(EventTarget* target,
  70                                               const LocatedEvent& event) const {
  71   return true;
  72 }
  73
  74 }  // namespace ui