gesture_nav_simple.cc revision 010d83a9304c5a91596085d917d248abff47903a 
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 "content/browser/web_contents/aura/gesture_nav_simple.h"
6
7#include "cc/layers/layer.h"
8#include "content/browser/frame_host/navigation_controller_impl.h"
9#include "content/browser/renderer_host/overscroll_controller.h"
10#include "content/browser/web_contents/web_contents_impl.h"
11#include "content/browser/web_contents/web_contents_view.h"
12#include "content/public/browser/overscroll_configuration.h"
13#include "content/public/common/content_client.h"
14#include "grit/ui_resources.h"
15#include "ui/aura/window.h"
16#include "ui/compositor/layer.h"
17#include "ui/compositor/layer_animation_observer.h"
18#include "ui/compositor/layer_delegate.h"
19#include "ui/compositor/scoped_layer_animation_settings.h"
20#include "ui/gfx/animation/tween.h"
21#include "ui/gfx/canvas.h"
22#include "ui/gfx/image/image.h"
23
24namespace content {
25
26namespace {
27
28const int kArrowHeight = 280;
29const int kArrowWidth = 140;
30const float kMinOpacity = 0.25f;
31
32bool ShouldNavigateForward(const NavigationController& controller,
33                           OverscrollMode mode) {
34  return mode == (base::i18n::IsRTL() ? OVERSCROLL_EAST : OVERSCROLL_WEST) &&
35         controller.CanGoForward();
36}
37
38bool ShouldNavigateBack(const NavigationController& controller,
39                        OverscrollMode mode) {
40  return mode == (base::i18n::IsRTL() ? OVERSCROLL_WEST : OVERSCROLL_EAST) &&
41         controller.CanGoBack();
42}
43
44// An animation observers that deletes itself and a pointer after the end of the
45// animation.
46template <class T>
47class DeleteAfterAnimation : public ui::ImplicitAnimationObserver {
48 public:
49  explicit DeleteAfterAnimation(scoped_ptr<T> object)
50      : object_(object.Pass()) {}
51
52 private:
53  friend class base::DeleteHelper<DeleteAfterAnimation<T> >;
54
55  virtual ~DeleteAfterAnimation() {}
56
57  // ui::ImplicitAnimationObserver:
58  virtual void OnImplicitAnimationsCompleted() OVERRIDE {
59    // Deleting an observer when a ScopedLayerAnimationSettings is iterating
60    // over them can cause a crash (which can happen during tests). So instead,
61    // schedule this observer to be deleted soon.
62    BrowserThread::DeleteSoon(BrowserThread::UI, FROM_HERE, this);
63  }
64
65  scoped_ptr<T> object_;
66  DISALLOW_COPY_AND_ASSIGN(DeleteAfterAnimation);
67};
68
69}  // namespace
70
71// A layer delegate that paints the shield with the arrow in it.
72class ArrowLayerDelegate : public ui::LayerDelegate {
73 public:
74  explicit ArrowLayerDelegate(int resource_id)
75      : image_(GetContentClient()->GetNativeImageNamed(resource_id)),
76        left_arrow_(resource_id == IDR_BACK_ARROW) {
77    CHECK(!image_.IsEmpty());
78  }
79
80  virtual ~ArrowLayerDelegate() {}
81
82  bool left() const { return left_arrow_; }
83
84 private:
85  // ui::LayerDelegate:
86  virtual void OnPaintLayer(gfx::Canvas* canvas) OVERRIDE {
87    SkPaint paint;
88    paint.setColor(SkColorSetARGB(0xa0, 0, 0, 0));
89    paint.setStyle(SkPaint::kFill_Style);
90    paint.setAntiAlias(true);
91
92    canvas->DrawCircle(
93        gfx::Point(left_arrow_ ? 0 : kArrowWidth, kArrowHeight / 2),
94        kArrowWidth,
95        paint);
96    canvas->DrawImageInt(*image_.ToImageSkia(),
97                         left_arrow_ ? 0 : kArrowWidth - image_.Width(),
98                         (kArrowHeight - image_.Height()) / 2);
99  }
100
101  virtual void OnDeviceScaleFactorChanged(float device_scale_factor) OVERRIDE {}
102
103  virtual base::Closure PrepareForLayerBoundsChange() OVERRIDE {
104    return base::Closure();
105  }
106
107  const gfx::Image& image_;
108  const bool left_arrow_;
109
110  DISALLOW_COPY_AND_ASSIGN(ArrowLayerDelegate);
111};
112
113GestureNavSimple::GestureNavSimple(WebContentsImpl* web_contents)
114    : web_contents_(web_contents),
115      completion_threshold_(0.f) {}
116
117GestureNavSimple::~GestureNavSimple() {}
118
119void GestureNavSimple::ApplyEffectsAndDestroy(const gfx::Transform& transform,
120                                              float opacity) {
121  ui::Layer* layer = arrow_.get();
122  ui::ScopedLayerAnimationSettings settings(arrow_->GetAnimator());
123  settings.AddObserver(
124      new DeleteAfterAnimation<ArrowLayerDelegate>(arrow_delegate_.Pass()));
125  settings.AddObserver(new DeleteAfterAnimation<ui::Layer>(arrow_.Pass()));
126  settings.AddObserver(new DeleteAfterAnimation<ui::Layer>(clip_layer_.Pass()));
127  layer->SetTransform(transform);
128  layer->SetOpacity(opacity);
129}
130
131void GestureNavSimple::AbortGestureAnimation() {
132  if (!arrow_)
133    return;
134  gfx::Transform transform;
135  transform.Translate(arrow_delegate_->left() ? -kArrowWidth : kArrowWidth, 0);
136  ApplyEffectsAndDestroy(transform, kMinOpacity);
137}
138
139void GestureNavSimple::CompleteGestureAnimation() {
140  if (!arrow_)
141    return;
142  // Make sure the fade-out starts from the complete state.
143  ApplyEffectsForDelta(completion_threshold_);
144  ApplyEffectsAndDestroy(arrow_->transform(), 0.f);
145}
146
147void GestureNavSimple::ApplyEffectsForDelta(float delta_x) {
148  if (!arrow_)
149    return;
150  CHECK_GT(completion_threshold_, 0.f);
151  CHECK_GE(delta_x, 0.f);
152  double complete = std::min(1.f, delta_x / completion_threshold_);
153  float translate_x = gfx::Tween::FloatValueBetween(complete, -kArrowWidth, 0);
154  gfx::Transform transform;
155  transform.Translate(arrow_delegate_->left() ? translate_x : -translate_x,
156                      0.f);
157  arrow_->SetTransform(transform);
158  arrow_->SetOpacity(gfx::Tween::FloatValueBetween(complete, kMinOpacity, 1.f));
159}
160
161gfx::Rect GestureNavSimple::GetVisibleBounds() const {
162  return web_contents_->GetNativeView()->bounds();
163}
164
165void GestureNavSimple::OnOverscrollUpdate(float delta_x, float delta_y) {
166  ApplyEffectsForDelta(std::abs(delta_x) + 50.f);
167}
168
169void GestureNavSimple::OnOverscrollComplete(OverscrollMode overscroll_mode) {
170  CompleteGestureAnimation();
171
172  NavigationControllerImpl& controller = web_contents_->GetController();
173  if (ShouldNavigateForward(controller, overscroll_mode))
174    controller.GoForward();
175  else if (ShouldNavigateBack(controller, overscroll_mode))
176    controller.GoBack();
177}
178
179void GestureNavSimple::OnOverscrollModeChange(OverscrollMode old_mode,
180                                              OverscrollMode new_mode) {
181  NavigationControllerImpl& controller = web_contents_->GetController();
182  if (!ShouldNavigateForward(controller, new_mode) &&
183      !ShouldNavigateBack(controller, new_mode)) {
184    AbortGestureAnimation();
185    return;
186  }
187
188  arrow_.reset(new ui::Layer(ui::LAYER_TEXTURED));
189  // Note that RTL doesn't affect the arrow that should be displayed.
190  int resource_id = 0;
191  if (new_mode == OVERSCROLL_WEST)
192    resource_id = IDR_FORWARD_ARROW;
193  else if (new_mode == OVERSCROLL_EAST)
194    resource_id = IDR_BACK_ARROW;
195  else
196    NOTREACHED();
197
198  arrow_delegate_.reset(new ArrowLayerDelegate(resource_id));
199  arrow_->set_delegate(arrow_delegate_.get());
200  arrow_->SetFillsBoundsOpaquely(false);
201
202  aura::Window* window = web_contents_->GetNativeView();
203  const gfx::Rect& window_bounds = window->bounds();
204  completion_threshold_ = window_bounds.width() *
205      GetOverscrollConfig(OVERSCROLL_CONFIG_HORIZ_THRESHOLD_COMPLETE);
206
207  // Align on the left or right edge.
208  int x = (resource_id == IDR_BACK_ARROW) ? 0 :
209      (window_bounds.width() - kArrowWidth);
210  // Align in the center vertically.
211  int y = std::max(0, (window_bounds.height() - kArrowHeight) / 2);
212  arrow_->SetBounds(gfx::Rect(x, y, kArrowWidth, kArrowHeight));
213  ApplyEffectsForDelta(0.f);
214
215  // Adding the arrow as a child of the content window is not sufficient,
216  // because it is possible for a new layer to be parented on top of the arrow
217  // layer (e.g. when the navigated-to page is displayed while the completion
218  // animation is in progress). So instead, a clip layer (that doesn't paint) is
219  // installed on top of the content window as its sibling, and the arrow layer
220  // is added to that clip layer.
221  clip_layer_.reset(new ui::Layer(ui::LAYER_NOT_DRAWN));
222  clip_layer_->SetBounds(window->layer()->bounds());
223  clip_layer_->SetMasksToBounds(true);
224  clip_layer_->Add(arrow_.get());
225
226  ui::Layer* parent = window->layer()->parent();
227  parent->Add(clip_layer_.get());
228  parent->StackAtTop(clip_layer_.get());
229}
230
231}  // namespace content
232