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#include "ui/views/widget/root_view_targeter.h"
6
7#include "ui/views/view.h"
8#include "ui/views/view_targeter_delegate.h"
9#include "ui/views/views_switches.h"
10#include "ui/views/widget/root_view.h"
11#include "ui/views/widget/widget.h"
12
13namespace views {
14
15RootViewTargeter::RootViewTargeter(ViewTargeterDelegate* delegate,
16                                   internal::RootView* root_view)
17    : ViewTargeter(delegate), root_view_(root_view) {
18}
19
20RootViewTargeter::~RootViewTargeter() {
21}
22
23View* RootViewTargeter::FindTargetForGestureEvent(
24    View* root,
25    const ui::GestureEvent& gesture) {
26  CHECK_EQ(root, root_view_);
27
28  // Return the default gesture handler if one is already set.
29  if (root_view_->gesture_handler_) {
30    CHECK(root_view_->gesture_handler_set_before_processing_);
31    return root_view_->gesture_handler_;
32  }
33
34  // If no default gesture handler has already been set, do not perform any
35  // targeting for a ET_GESTURE_END event.
36  if (gesture.type() == ui::ET_GESTURE_END)
37    return NULL;
38
39  // If rect-based targeting is enabled, use the gesture's bounding box to
40  // determine the target. Otherwise use the center point of the gesture's
41  // bounding box to determine the target.
42  gfx::Rect rect(gesture.location(), gfx::Size(1, 1));
43  if (views::switches::IsRectBasedTargetingEnabled() &&
44      !gesture.details().bounding_box().IsEmpty()) {
45    // TODO(tdanderson): Pass in the bounding box to GetEventHandlerForRect()
46    // once crbug.com/313392 is resolved.
47    rect.set_size(gesture.details().bounding_box().size());
48    rect.Offset(-rect.width() / 2, -rect.height() / 2);
49  }
50
51  return root->GetEffectiveViewTargeter()->TargetForRect(root, rect);
52}
53
54ui::EventTarget* RootViewTargeter::FindNextBestTargetForGestureEvent(
55    ui::EventTarget* previous_target,
56    const ui::GestureEvent& gesture) {
57  // ET_GESTURE_END events should only ever be targeted to the default
58  // gesture handler set by a previous gesture, if one exists. Thus we do not
59  // permit any re-targeting of ET_GESTURE_END events.
60  if (gesture.type() == ui::ET_GESTURE_END)
61    return NULL;
62
63  // Prohibit re-targeting of gesture events (except for GESTURE_SCROLL_BEGIN
64  // events) if the default gesture handler was set by the dispatch of a
65  // previous gesture event.
66  if (root_view_->gesture_handler_set_before_processing_ &&
67      gesture.type() != ui::ET_GESTURE_SCROLL_BEGIN) {
68    return NULL;
69  }
70
71  // If |gesture_handler_| is NULL, it is either because the view was removed
72  // from the tree by the previous dispatch of |gesture| or because |gesture| is
73  // the GESTURE_END event corresponding to the removal of the last touch
74  // point. In either case, no further re-targeting of |gesture| should be
75  // permitted.
76  if (!root_view_->gesture_handler_)
77    return NULL;
78
79  return previous_target->GetParentTarget();
80}
81
82}  // namespace views
83