Prevent overlay scrollbars expand or hover together

cc/input/single_scrollbar_animation_controller_thinning.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "cc/input/scrollbar_animation_controller_thinning.h"
+#include "cc/input/single_scrollbar_animation_controller_thinning.h"
+
+#include <limits>
+#include <vector>
 
 #include "base/memory/ptr_util.h"
 #include "base/time/time.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/layers/scrollbar_layer_impl_base.h"
 #include "cc/trees/layer_tree_impl.h"
 
 namespace {
 const float kIdleThicknessScale = 0.4f;
 const float kDefaultMouseMoveDistanceToTriggerAnimation = 25.f;
 }
 
 namespace cc {
 
-std::unique_ptr<ScrollbarAnimationControllerThinning>
-ScrollbarAnimationControllerThinning::Create(
+using std::vector;
+
+std::unique_ptr<SingleScrollbarAnimationControllerThinning>
+SingleScrollbarAnimationControllerThinning::Create(
     int scroll_layer_id,
+    ScrollbarOrientation orientation,
     ScrollbarAnimationControllerClient* client,
     base::TimeDelta delay_before_starting,
     base::TimeDelta resize_delay_before_starting,
     base::TimeDelta fade_duration,
     base::TimeDelta thinning_duration) {
-  return base::WrapUnique(new ScrollbarAnimationControllerThinning(
-      scroll_layer_id, client, delay_before_starting,
+  return base::WrapUnique(new SingleScrollbarAnimationControllerThinning(
+      scroll_layer_id, orientation, client, delay_before_starting,
       resize_delay_before_starting, fade_duration, thinning_duration));
 }
 
-ScrollbarAnimationControllerThinning::ScrollbarAnimationControllerThinning(
-    int scroll_layer_id,
-    ScrollbarAnimationControllerClient* client,
-    base::TimeDelta delay_before_starting,
-    base::TimeDelta resize_delay_before_starting,
-    base::TimeDelta fade_duration,
-    base::TimeDelta thinning_duration)
+SingleScrollbarAnimationControllerThinning::
+    SingleScrollbarAnimationControllerThinning(
+        int scroll_layer_id,
+        ScrollbarOrientation orientation,
+        ScrollbarAnimationControllerClient* client,
+        base::TimeDelta delay_before_starting,
+        base::TimeDelta resize_delay_before_starting,
+        base::TimeDelta fade_duration,
+        base::TimeDelta thinning_duration)
     : ScrollbarAnimationController(scroll_layer_id,
                                    client,
                                    delay_before_starting,
                                    resize_delay_before_starting),
+      orientation_(orientation),
       opacity_(0.0f),
       captured_(false),
       mouse_is_over_scrollbar_(false),
       mouse_is_near_scrollbar_(false),
       thickness_change_(NONE),
       mouse_move_distance_to_trigger_animation_(
           kDefaultMouseMoveDistanceToTriggerAnimation),
       fade_duration_(fade_duration),
       thinning_duration_(thinning_duration),
       current_animating_property_(OPACITY) {
   ApplyOpacity(0.f);
   ApplyThumbThicknessScale(kIdleThicknessScale);
 }
 
-ScrollbarAnimationControllerThinning::~ScrollbarAnimationControllerThinning() {}
-
-void ScrollbarAnimationControllerThinning::RunAnimationFrame(float progress) {
+void SingleScrollbarAnimationControllerThinning::RunAnimationFrame(
+    float progress) {
   if (captured_)
     return;
 
   if (current_animating_property_ == OPACITY)
     ApplyOpacity(1.f - progress);
   else
     ApplyThumbThicknessScale(ThumbThicknessScaleAt(progress));
 
   client_->SetNeedsRedrawForScrollbarAnimation();
   if (progress == 1.f) {
     StopAnimation();
     if (current_animating_property_ == THICKNESS) {
       thickness_change_ = NONE;
       SetCurrentAnimatingProperty(OPACITY);
       PostDelayedAnimationTask(false);
     }
   }
 }
 
-const base::TimeDelta& ScrollbarAnimationControllerThinning::Duration() {
+const base::TimeDelta& SingleScrollbarAnimationControllerThinning::Duration() {
   if (current_animating_property_ == OPACITY)
     return fade_duration_;
   else
     return thinning_duration_;
 }
 
-void ScrollbarAnimationControllerThinning::DidMouseDown() {
+void SingleScrollbarAnimationControllerThinning::DidMouseDown() {
   if (!mouse_is_over_scrollbar_ || opacity_ == 0.0f)
     return;
 
   StopAnimation();
   captured_ = true;
   ApplyOpacity(1.f);
   ApplyThumbThicknessScale(1.f);
 }
 
-void ScrollbarAnimationControllerThinning::DidMouseUp() {
+void SingleScrollbarAnimationControllerThinning::DidMouseUp() {
   if (!captured_ || opacity_ == 0.0f)
     return;
 
   captured_ = false;
   StopAnimation();
 
   if (!mouse_is_near_scrollbar_) {
     SetCurrentAnimatingProperty(THICKNESS);
     thickness_change_ = DECREASE;
     StartAnimation();
   } else {
     SetCurrentAnimatingProperty(OPACITY);
     PostDelayedAnimationTask(false);
   }
 }
 
-void ScrollbarAnimationControllerThinning::DidMouseLeave() {
+void SingleScrollbarAnimationControllerThinning::DidMouseLeave() {
   if (!mouse_is_over_scrollbar_ && !mouse_is_near_scrollbar_)
     return;
 
   mouse_is_over_scrollbar_ = false;
   mouse_is_near_scrollbar_ = false;
 
   if (captured_ || opacity_ == 0.0f)
     return;
 
   thickness_change_ = DECREASE;
   SetCurrentAnimatingProperty(THICKNESS);
   StartAnimation();
 }
 
-void ScrollbarAnimationControllerThinning::DidScrollUpdate(bool on_resize) {
+void SingleScrollbarAnimationControllerThinning::DidScrollUpdate(
+    bool on_resize) {
   if (captured_)
     return;
 
   ScrollbarAnimationController::DidScrollUpdate(on_resize);
   ApplyOpacity(1.f);
   ApplyThumbThicknessScale(mouse_is_near_scrollbar_ ? 1.f
                                                     : kIdleThicknessScale);
   SetCurrentAnimatingProperty(OPACITY);
 }
 
-void ScrollbarAnimationControllerThinning::DidMouseMoveNear(float distance) {
+void SingleScrollbarAnimationControllerThinning::DidMouseMoveNear(
+    vector<DistanceToScrollbar> distances) {
+  float distance = std::numeric_limits<float>::max();
+  for (DistanceToScrollbar& distance_to_scrollbar : distances) {
+    if (distance_to_scrollbar.orientation_ == orientation_) {
+      distance = distance_to_scrollbar.distance_;
+    }
+  }
+
   bool mouse_is_over_scrollbar = distance == 0.0f;
   bool mouse_is_near_scrollbar =
       distance < mouse_move_distance_to_trigger_animation_;
 
   if (captured_ || opacity_ == 0.0f) {
     mouse_is_near_scrollbar_ = mouse_is_near_scrollbar;
     mouse_is_over_scrollbar_ = mouse_is_over_scrollbar;
     return;
   }
 
   if (mouse_is_over_scrollbar == mouse_is_over_scrollbar_ &&
       mouse_is_near_scrollbar == mouse_is_near_scrollbar_)
     return;
 
   if (mouse_is_over_scrollbar_ != mouse_is_over_scrollbar)
     mouse_is_over_scrollbar_ = mouse_is_over_scrollbar;
 
   if (mouse_is_near_scrollbar_ != mouse_is_near_scrollbar) {
     mouse_is_near_scrollbar_ = mouse_is_near_scrollbar;
     thickness_change_ = mouse_is_near_scrollbar_ ? INCREASE : DECREASE;
   }
 
   SetCurrentAnimatingProperty(THICKNESS);
   StartAnimation();
 }
 
-bool ScrollbarAnimationControllerThinning::ScrollbarsHidden() const {
+bool SingleScrollbarAnimationControllerThinning::ScrollbarsHidden() const {
   return opacity_ == 0.0f;
 }
 
-float ScrollbarAnimationControllerThinning::ThumbThicknessScaleAt(
+float SingleScrollbarAnimationControllerThinning::ThumbThicknessScaleAt(
     float progress) {
   if (thickness_change_ == NONE)
     return mouse_is_near_scrollbar_ ? 1.f : kIdleThicknessScale;
   float factor = thickness_change_ == INCREASE ? progress : (1.f - progress);
   return ((1.f - kIdleThicknessScale) * factor) + kIdleThicknessScale;
 }
 
-float ScrollbarAnimationControllerThinning::AdjustScale(
+float SingleScrollbarAnimationControllerThinning::AdjustScale(
     float new_value,
     float current_value,
     AnimationChange animation_change,
     float min_value,
     float max_value) {
   float result;
   if (animation_change == INCREASE && current_value > new_value)
     result = current_value;
   else if (animation_change == DECREASE && current_value < new_value)
     result = current_value;
   else
     result = new_value;
   if (result > max_value)
     return max_value;
   if (result < min_value)
     return min_value;
   return result;
 }
 
-void ScrollbarAnimationControllerThinning::ApplyOpacity(float opacity) {
+void SingleScrollbarAnimationControllerThinning::ApplyOpacity(float opacity) {
   for (ScrollbarLayerImplBase* scrollbar : Scrollbars()) {
+    if (scrollbar->orientation() != orientation_)
+      continue;
     if (!scrollbar->is_overlay_scrollbar())
       continue;
+
     float effective_opacity = scrollbar->CanScrollOrientation() ? opacity : 0;
     PropertyTrees* property_trees =
         scrollbar->layer_tree_impl()->property_trees();
     // If this method is called during LayerImpl::PushPropertiesTo, we may not
     // yet have valid effect_id_to_index_map entries as property trees are
     // pushed after layers during activation. We can skip updating opacity in
     // that case as we are only registering a scrollbar and because opacity will
     // be overwritten anyway when property trees are pushed.
     if (property_trees->IsInIdToIndexMap(PropertyTrees::TreeType::EFFECT,
                                          scrollbar->id())) {
       property_trees->effect_tree.OnOpacityAnimated(
           effective_opacity,
           property_trees->effect_id_to_index_map[scrollbar->id()],
           scrollbar->layer_tree_impl());
     }
   }
 
   bool previouslyVisible = opacity_ > 0.0f;
   bool currentlyVisible = opacity > 0.0f;
 
   opacity_ = opacity;
 
   if (previouslyVisible != currentlyVisible)
     client_->DidChangeScrollbarVisibility();
 }
 
-void ScrollbarAnimationControllerThinning::ApplyThumbThicknessScale(
+void SingleScrollbarAnimationControllerThinning::ApplyThumbThicknessScale(
     float thumb_thickness_scale) {
   for (ScrollbarLayerImplBase* scrollbar : Scrollbars()) {
+    if (scrollbar->orientation() != orientation_)
+      continue;
     if (!scrollbar->is_overlay_scrollbar())
       continue;
 
-    scrollbar->SetThumbThicknessScaleFactor(AdjustScale(
-        thumb_thickness_scale, scrollbar->thumb_thickness_scale_factor(),
-        thickness_change_, kIdleThicknessScale, 1));
+    float scale = AdjustScale(thumb_thickness_scale,
+                              scrollbar->thumb_thickness_scale_factor(),
+                              thickness_change_, kIdleThicknessScale, 1);
+
+    scrollbar->SetThumbThicknessScaleFactor(scale);
   }
 }
 
-void ScrollbarAnimationControllerThinning::SetCurrentAnimatingProperty(
+void SingleScrollbarAnimationControllerThinning::SetCurrentAnimatingProperty(
     AnimatingProperty property) {
   if (current_animating_property_ == property)
     return;
 
   StopAnimation();
   current_animating_property_ = property;
   if (current_animating_property_ == THICKNESS)
     ApplyOpacity(1.f);
 }
 
 }  // namespace cc