src/content/browser/web_contents/aura/gesture_nav_simple.cc

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