cc/animation/scrollbar_animation_controller_thinning.h

   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 #ifndef CC_ANIMATION_SCROLLBAR_ANIMATION_CONTROLLER_THINNING_H_
   6 #define CC_ANIMATION_SCROLLBAR_ANIMATION_CONTROLLER_THINNING_H_
   7
   8 #include "base/memory/scoped_ptr.h"
   9 #include "cc/animation/scrollbar_animation_controller.h"
  10 #include "cc/base/cc_export.h"
  11
  12 namespace cc {
  13 class LayerImpl;
  14
  15 // Scrollbar animation that partially fades and thins after an idle delay,
  16 // and reacts to mouse movements.
  17 class CC_EXPORT ScrollbarAnimationControllerThinning
  18     : public ScrollbarAnimationController {
  19  public:
  20   static scoped_ptr<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
  27   ~ScrollbarAnimationControllerThinning() override;
  28
  29   void set_mouse_move_distance_for_test(float distance) {
  30     mouse_move_distance_to_trigger_animation_ = distance;
  31   }
  32   bool mouse_is_over_scrollbar() const { return mouse_is_over_scrollbar_; }
  33   bool mouse_is_near_scrollbar() const { return mouse_is_near_scrollbar_; }
  34
  35   void DidScrollUpdate(bool on_resize) override;
  36   void DidMouseMoveOffScrollbar() override;
  37   void DidMouseMoveNear(float distance) override;
  38
  39  protected:
  40   ScrollbarAnimationControllerThinning(
  41       LayerImpl* scroll_layer,
  42       ScrollbarAnimationControllerClient* client,
  43       base::TimeDelta delay_before_starting,
  44       base::TimeDelta resize_delay_before_starting,
  45       base::TimeDelta duration);
  46
  47   void RunAnimationFrame(float progress) override;
  48
  49  private:
  50   // Describes whether the current animation should INCREASE (darken / thicken)
  51   // a bar or DECREASE it (lighten / thin).
  52   enum AnimationChange {
  53     NONE,
  54     INCREASE,
  55     DECREASE
  56   };
  57   float OpacityAtAnimationProgress(float progress);
  58   float ThumbThicknessScaleAtAnimationProgress(float progress);
  59   float AdjustScale(float new_value,
  60                     float current_value,
  61                     AnimationChange animation_change);
  62   void ApplyOpacityAndThumbThicknessScale(float opacity,
  63                                           float thumb_thickness_scale);
  64
  65   LayerImpl* scroll_layer_;
  66
  67   bool mouse_is_over_scrollbar_;
  68   bool mouse_is_near_scrollbar_;
  69   // Are we narrowing or thickening the bars.
  70   AnimationChange thickness_change_;
  71   // Are we darkening or lightening the bars.
  72   AnimationChange opacity_change_;
  73   // How close should the mouse be to the scrollbar before we thicken it.
  74   float mouse_move_distance_to_trigger_animation_;
  75
  76   DISALLOW_COPY_AND_ASSIGN(ScrollbarAnimationControllerThinning);
  77 };
  78
  79 }  // namespace cc
  80
  81 #endif  // CC_ANIMATION_SCROLLBAR_ANIMATION_CONTROLLER_THINNING_H_