cc/animation/scrollbar_animation_controller_thinning.cc

   1 // Copyright 2013 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 "cc/animation/scrollbar_animation_controller_thinning.h"
   6
   7 #include "base/time/time.h"
   8 #include "cc/layers/layer_impl.h"
   9 #include "cc/layers/scrollbar_layer_impl_base.h"
  10
  11 namespace {
  12 const float kIdleThicknessScale = 0.4f;
  13 const float kIdleOpacity = 0.7f;
  14 const float kDefaultMouseMoveDistanceToTriggerAnimation = 25.f;
  15 }
  16
  17 namespace cc {
  18
  19 scoped_ptr<ScrollbarAnimationControllerThinning>
  20 ScrollbarAnimationControllerThinning::Create(
  21     LayerImpl* scroll_layer,
  22     ScrollbarAnimationControllerClient* client,
  23     base::TimeDelta delay_before_starting,
  24     base::TimeDelta resize_delay_before_starting,
  25     base::TimeDelta duration) {
  26   return make_scoped_ptr(
  27       new ScrollbarAnimationControllerThinning(scroll_layer,
  28                                                client,
  29                                                delay_before_starting,
  30                                                resize_delay_before_starting,
  31                                                duration));
  32 }
  33
  34 ScrollbarAnimationControllerThinning::ScrollbarAnimationControllerThinning(
  35     LayerImpl* scroll_layer,
  36     ScrollbarAnimationControllerClient* client,
  37     base::TimeDelta delay_before_starting,
  38     base::TimeDelta resize_delay_before_starting,
  39     base::TimeDelta duration)
  40     : ScrollbarAnimationController(client,
  41                                    delay_before_starting,
  42                                    resize_delay_before_starting,
  43                                    duration),
  44       scroll_layer_(scroll_layer),
  45       mouse_is_over_scrollbar_(false),
  46       mouse_is_near_scrollbar_(false),
  47       thickness_change_(NONE),
  48       opacity_change_(NONE),
  49       mouse_move_distance_to_trigger_animation_(
  50           kDefaultMouseMoveDistanceToTriggerAnimation) {
  51   ApplyOpacityAndThumbThicknessScale(kIdleOpacity, kIdleThicknessScale);
  52 }
  53
  54 ScrollbarAnimationControllerThinning::~ScrollbarAnimationControllerThinning() {
  55 }
  56
  57 void ScrollbarAnimationControllerThinning::RunAnimationFrame(float progress) {
  58   float opacity = OpacityAtAnimationProgress(progress);
  59   float thumb_thickness_scale = ThumbThicknessScaleAtAnimationProgress(
  60       progress);
  61   ApplyOpacityAndThumbThicknessScale(opacity, thumb_thickness_scale);
  62   if (progress == 1.f) {
  63     opacity_change_ = NONE;
  64     thickness_change_ = NONE;
  65     StopAnimation();
  66   }
  67 }
  68
  69 void ScrollbarAnimationControllerThinning::DidMouseMoveOffScrollbar() {
  70   mouse_is_over_scrollbar_ = false;
  71   mouse_is_near_scrollbar_ = false;
  72   opacity_change_ = DECREASE;
  73   thickness_change_ = DECREASE;
  74   StartAnimation();
  75 }
  76
  77 void ScrollbarAnimationControllerThinning::DidScrollUpdate(bool on_resize) {
  78   ScrollbarAnimationController::DidScrollUpdate(on_resize);
  79   ApplyOpacityAndThumbThicknessScale(
  80     1, mouse_is_near_scrollbar_ ? 1.f : kIdleThicknessScale);
  81
  82   if (!mouse_is_over_scrollbar_)
  83     opacity_change_ = DECREASE;
  84 }
  85
  86 void ScrollbarAnimationControllerThinning::DidMouseMoveNear(float distance) {
  87   bool mouse_is_over_scrollbar = distance == 0.0;
  88   bool mouse_is_near_scrollbar =
  89       distance < mouse_move_distance_to_trigger_animation_;
  90
  91   if (mouse_is_over_scrollbar == mouse_is_over_scrollbar_ &&
  92       mouse_is_near_scrollbar == mouse_is_near_scrollbar_)
  93     return;
  94
  95   if (mouse_is_over_scrollbar_ != mouse_is_over_scrollbar) {
  96     mouse_is_over_scrollbar_ = mouse_is_over_scrollbar;
  97     opacity_change_ = mouse_is_over_scrollbar_ ? INCREASE : DECREASE;
  98   }
  99
 100   if (mouse_is_near_scrollbar_ != mouse_is_near_scrollbar) {
 101     mouse_is_near_scrollbar_ = mouse_is_near_scrollbar;
 102     thickness_change_ = mouse_is_near_scrollbar_ ? INCREASE : DECREASE;
 103   }
 104
 105   StartAnimation();
 106 }
 107
 108 float ScrollbarAnimationControllerThinning::OpacityAtAnimationProgress(
 109     float progress) {
 110   if (opacity_change_ == NONE)
 111     return mouse_is_over_scrollbar_ ? 1.f : kIdleOpacity;
 112   float factor = opacity_change_ == INCREASE ? progress : (1.f - progress);
 113   float ret = ((1.f - kIdleOpacity) * factor) + kIdleOpacity;
 114   return ret;
 115 }
 116
 117 float
 118 ScrollbarAnimationControllerThinning::ThumbThicknessScaleAtAnimationProgress(
 119     float progress) {
 120   if (thickness_change_ == NONE)
 121     return mouse_is_near_scrollbar_ ? 1.f : kIdleThicknessScale;
 122   float factor = thickness_change_ == INCREASE ? progress : (1.f - progress);
 123   return ((1.f - kIdleThicknessScale) * factor) + kIdleThicknessScale;
 124 }
 125
 126 float ScrollbarAnimationControllerThinning::AdjustScale(
 127     float new_value,
 128     float current_value,
 129     AnimationChange animation_change) {
 130   if (animation_change == INCREASE && current_value > new_value)
 131     return current_value;
 132   if (animation_change == DECREASE && current_value < new_value)
 133     return current_value;
 134   return new_value;
 135 }
 136
 137 void ScrollbarAnimationControllerThinning::ApplyOpacityAndThumbThicknessScale(
 138     float opacity, float thumb_thickness_scale) {
 139   if (!scroll_layer_->scrollbars())
 140     return;
 141
 142   LayerImpl::ScrollbarSet* scrollbars = scroll_layer_->scrollbars();
 143   for (LayerImpl::ScrollbarSet::iterator it = scrollbars->begin();
 144        it != scrollbars->end();
 145        ++it) {
 146     ScrollbarLayerImplBase* scrollbar = *it;
 147     if (scrollbar->is_overlay_scrollbar()) {
 148       float effectiveOpacity =
 149           scrollbar->CanScrollOrientation()
 150               ? AdjustScale(opacity, scrollbar->opacity(), opacity_change_)
 151               : 0;
 152
 153       scrollbar->SetOpacity(effectiveOpacity);
 154       scrollbar->SetThumbThicknessScaleFactor(
 155           AdjustScale(thumb_thickness_scale,
 156                       scrollbar->thumb_thickness_scale_factor(),
 157                       thickness_change_));
 158     }
 159   }
 160 }
 161
 162 }  // namespace cc