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 "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/paint_context.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 #include "ui/resources/grit/ui_resources.h"
  25
  26 namespace content {
  27
  28 namespace {
  29
  30 const int kArrowHeight = 280;
  31 const int kArrowWidth = 140;
  32 const float kMinOpacity = 0.25f;
  33
  34 bool ShouldNavigateForward(const NavigationController& controller,
  35                            OverscrollMode mode) {
  36   return mode == (base::i18n::IsRTL() ? OVERSCROLL_EAST : OVERSCROLL_WEST) &&
  37          controller.CanGoForward();
  38 }
  39
  40 bool ShouldNavigateBack(const NavigationController& controller,
  41                         OverscrollMode mode) {
  42   return mode == (base::i18n::IsRTL() ? OVERSCROLL_WEST : OVERSCROLL_EAST) &&
  43          controller.CanGoBack();
  44 }
  45
  46 // An animation observers that deletes itself and a pointer after the end of the
  47 // animation.
  48 template <class T>
  49 class DeleteAfterAnimation : public ui::ImplicitAnimationObserver {
  50  public:
  51   explicit DeleteAfterAnimation(scoped_ptr<T> object)
  52       : object_(object.Pass()) {}
  53
  54  private:
  55   friend class base::DeleteHelper<DeleteAfterAnimation<T> >;
  56
  57   virtual ~DeleteAfterAnimation() {}
  58
  59   // ui::ImplicitAnimationObserver:
  60   virtual void OnImplicitAnimationsCompleted() override {
  61     // Deleting an observer when a ScopedLayerAnimationSettings is iterating
  62     // over them can cause a crash (which can happen during tests). So instead,
  63     // schedule this observer to be deleted soon.
  64     BrowserThread::DeleteSoon(BrowserThread::UI, FROM_HERE, this);
  65   }
  66
  67   scoped_ptr<T> object_;
  68   DISALLOW_COPY_AND_ASSIGN(DeleteAfterAnimation);
  69 };
  70
  71 }  // namespace
  72
  73 // A layer delegate that paints the shield with the arrow in it.
  74 class ArrowLayerDelegate : public ui::LayerDelegate {
  75  public:
  76   explicit ArrowLayerDelegate(int resource_id)
  77       : image_(GetContentClient()->GetNativeImageNamed(resource_id)),
  78         left_arrow_(resource_id == IDR_BACK_ARROW) {
  79     CHECK(!image_.IsEmpty());
  80   }
  81
  82   ~ArrowLayerDelegate() override {}
  83
  84   bool left() const { return left_arrow_; }
  85
  86  private:
  87   // ui::LayerDelegate:
  88   void OnPaintLayer(const ui::PaintContext& context) override {
  89     SkPaint paint;
  90     paint.setColor(SkColorSetARGB(0xa0, 0, 0, 0));
  91     paint.setStyle(SkPaint::kFill_Style);
  92     paint.setAntiAlias(true);
  93
  94     gfx::Canvas* canvas = context.canvas();
  95     canvas->DrawCircle(
  96         gfx::Point(left_arrow_ ? 0 : kArrowWidth, kArrowHeight / 2),
  97         kArrowWidth,
  98         paint);
  99     canvas->DrawImageInt(*image_.ToImageSkia(),
 100                          left_arrow_ ? 0 : kArrowWidth - image_.Width(),
 101                          (kArrowHeight - image_.Height()) / 2);
 102   }
 103
 104   void OnDelegatedFrameDamage(const gfx::Rect& damage_rect_in_dip) override {}
 105
 106   void OnDeviceScaleFactorChanged(float device_scale_factor) override {}
 107
 108   base::Closure PrepareForLayerBoundsChange() override {
 109     return base::Closure();
 110   }
 111
 112   const gfx::Image& image_;
 113   const bool left_arrow_;
 114
 115   DISALLOW_COPY_AND_ASSIGN(ArrowLayerDelegate);
 116 };
 117
 118 GestureNavSimple::GestureNavSimple(WebContentsImpl* web_contents)
 119     : web_contents_(web_contents),
 120       completion_threshold_(0.f) {}
 121
 122 GestureNavSimple::~GestureNavSimple() {}
 123
 124 void GestureNavSimple::ApplyEffectsAndDestroy(const gfx::Transform& transform,
 125                                               float opacity) {
 126   ui::Layer* layer = arrow_.get();
 127   ui::ScopedLayerAnimationSettings settings(arrow_->GetAnimator());
 128   settings.AddObserver(
 129       new DeleteAfterAnimation<ArrowLayerDelegate>(arrow_delegate_.Pass()));
 130   settings.AddObserver(new DeleteAfterAnimation<ui::Layer>(arrow_.Pass()));
 131   settings.AddObserver(new DeleteAfterAnimation<ui::Layer>(clip_layer_.Pass()));
 132   layer->SetTransform(transform);
 133   layer->SetOpacity(opacity);
 134 }
 135
 136 void GestureNavSimple::AbortGestureAnimation() {
 137   if (!arrow_)
 138     return;
 139   gfx::Transform transform;
 140   transform.Translate(arrow_delegate_->left() ? -kArrowWidth : kArrowWidth, 0);
 141   ApplyEffectsAndDestroy(transform, kMinOpacity);
 142 }
 143
 144 void GestureNavSimple::CompleteGestureAnimation() {
 145   if (!arrow_)
 146     return;
 147   // Make sure the fade-out starts from the complete state.
 148   ApplyEffectsForDelta(completion_threshold_);
 149   ApplyEffectsAndDestroy(arrow_->transform(), 0.f);
 150 }
 151
 152 bool GestureNavSimple::ApplyEffectsForDelta(float delta_x) {
 153   if (!arrow_)
 154     return false;
 155   CHECK_GT(completion_threshold_, 0.f);
 156   CHECK_GE(delta_x, 0.f);
 157   double complete = std::min(1.f, delta_x / completion_threshold_);
 158   float translate_x = gfx::Tween::FloatValueBetween(complete, -kArrowWidth, 0);
 159   gfx::Transform transform;
 160   transform.Translate(arrow_delegate_->left() ? translate_x : -translate_x,
 161                       0.f);
 162   arrow_->SetTransform(transform);
 163   arrow_->SetOpacity(gfx::Tween::FloatValueBetween(complete, kMinOpacity, 1.f));
 164   return true;
 165 }
 166
 167 gfx::Rect GestureNavSimple::GetVisibleBounds() const {
 168   return web_contents_->GetNativeView()->bounds();
 169 }
 170
 171 bool GestureNavSimple::OnOverscrollUpdate(float delta_x, float delta_y) {
 172   return ApplyEffectsForDelta(std::abs(delta_x) + 50.f);
 173 }
 174
 175 void GestureNavSimple::OnOverscrollComplete(OverscrollMode overscroll_mode) {
 176   CompleteGestureAnimation();
 177
 178   NavigationControllerImpl& controller = web_contents_->GetController();
 179   if (ShouldNavigateForward(controller, overscroll_mode))
 180     controller.GoForward();
 181   else if (ShouldNavigateBack(controller, overscroll_mode))
 182     controller.GoBack();
 183 }
 184
 185 void GestureNavSimple::OnOverscrollModeChange(OverscrollMode old_mode,
 186                                               OverscrollMode new_mode) {
 187   NavigationControllerImpl& controller = web_contents_->GetController();
 188   if (!ShouldNavigateForward(controller, new_mode) &&
 189       !ShouldNavigateBack(controller, new_mode)) {
 190     AbortGestureAnimation();
 191     return;
 192   }
 193
 194   arrow_.reset(new ui::Layer(ui::LAYER_TEXTURED));
 195   // Note that RTL doesn't affect the arrow that should be displayed.
 196   int resource_id = 0;
 197   if (new_mode == OVERSCROLL_WEST)
 198     resource_id = IDR_FORWARD_ARROW;
 199   else if (new_mode == OVERSCROLL_EAST)
 200     resource_id = IDR_BACK_ARROW;
 201   else
 202     NOTREACHED();
 203
 204   arrow_delegate_.reset(new ArrowLayerDelegate(resource_id));
 205   arrow_->set_delegate(arrow_delegate_.get());
 206   arrow_->SetFillsBoundsOpaquely(false);
 207
 208   aura::Window* window = web_contents_->GetNativeView();
 209   const gfx::Rect& window_bounds = window->bounds();
 210   completion_threshold_ = window_bounds.width() *
 211       GetOverscrollConfig(OVERSCROLL_CONFIG_HORIZ_THRESHOLD_COMPLETE);
 212
 213   // Align on the left or right edge.
 214   int x = (resource_id == IDR_BACK_ARROW) ? 0 :
 215       (window_bounds.width() - kArrowWidth);
 216   // Align in the center vertically.
 217   int y = std::max(0, (window_bounds.height() - kArrowHeight) / 2);
 218   arrow_->SetBounds(gfx::Rect(x, y, kArrowWidth, kArrowHeight));
 219   ApplyEffectsForDelta(0.f);
 220
 221   // Adding the arrow as a child of the content window is not sufficient,
 222   // because it is possible for a new layer to be parented on top of the arrow
 223   // layer (e.g. when the navigated-to page is displayed while the completion
 224   // animation is in progress). So instead, a clip layer (that doesn't paint) is
 225   // installed on top of the content window as its sibling, and the arrow layer
 226   // is added to that clip layer.
 227   clip_layer_.reset(new ui::Layer(ui::LAYER_NOT_DRAWN));
 228   clip_layer_->SetBounds(window->layer()->bounds());
 229   clip_layer_->SetMasksToBounds(true);
 230   clip_layer_->Add(arrow_.get());
 231
 232   ui::Layer* parent = window->layer()->parent();
 233   parent->Add(clip_layer_.get());
 234   parent->StackAtTop(clip_layer_.get());
 235 }
 236
 237 }  // namespace content