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/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
  24 namespace content {
  25
  26 namespace {
  27
  28 const int kArrowHeight = 280;
  29 const int kArrowWidth = 140;
  30 const float kMinOpacity = 0.25f;
  31
  32 bool ShouldNavigateForward(const NavigationController& controller,
  33                            OverscrollMode mode) {
  34   return mode == (base::i18n::IsRTL() ? OVERSCROLL_EAST : OVERSCROLL_WEST) &&
  35          controller.CanGoForward();
  36 }
  37
  38 bool 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.
  46 template <class T>
  47 class 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.
  72 class 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
 113 GestureNavSimple::GestureNavSimple(WebContentsImpl* web_contents)
 114     : web_contents_(web_contents),
 115       completion_threshold_(0.f) {}
 116
 117 GestureNavSimple::~GestureNavSimple() {}
 118
 119 void 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
 131 void 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
 139 void 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
 147 void 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
 161 gfx::Rect GestureNavSimple::GetVisibleBounds() const {
 162   return web_contents_->GetNativeView()->bounds();
 163 }
 164
 165 void GestureNavSimple::OnOverscrollUpdate(float delta_x, float delta_y) {
 166   ApplyEffectsForDelta(std::abs(delta_x) + 50.f);
 167 }
 168
 169 void 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
 179 void 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