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 duration);
  25
  26   virtual ~ScrollbarAnimationControllerThinning();
  27
  28   void set_mouse_move_distance_for_test(float distance) {
  29     mouse_move_distance_to_trigger_animation_ = distance;
  30   }
  31   bool mouse_is_over_scrollbar() const { return mouse_is_over_scrollbar_; }
  32   bool mouse_is_near_scrollbar() const { return mouse_is_near_scrollbar_; }
  33
  34   virtual void DidScrollUpdate() OVERRIDE;
  35   virtual void DidMouseMoveOffScrollbar() OVERRIDE;
  36   virtual void DidMouseMoveNear(float distance) OVERRIDE;
  37
  38  protected:
  39   ScrollbarAnimationControllerThinning(
  40       LayerImpl* scroll_layer,
  41       ScrollbarAnimationControllerClient* client,
  42       base::TimeDelta delay_before_starting,
  43       base::TimeDelta duration);
  44
  45   virtual void RunAnimationFrame(float progress) OVERRIDE;
  46
  47  private:
  48   // Describes whether the current animation should INCREASE (darken / thicken)
  49   // a bar or DECREASE it (lighten / thin).
  50   enum AnimationChange {
  51     NONE,
  52     INCREASE,
  53     DECREASE
  54   };
  55   float OpacityAtAnimationProgress(float progress);
  56   float ThumbThicknessScaleAtAnimationProgress(float progress);
  57   float AdjustScale(float new_value,
  58                     float current_value,
  59                     AnimationChange animation_change);
  60   void ApplyOpacityAndThumbThicknessScale(float opacity,
  61                                           float thumb_thickness_scale);
  62
  63   LayerImpl* scroll_layer_;
  64
  65   bool mouse_is_over_scrollbar_;
  66   bool mouse_is_near_scrollbar_;
  67   // Are we narrowing or thickening the bars.
  68   AnimationChange thickness_change_;
  69   // Are we darkening or lightening the bars.
  70   AnimationChange opacity_change_;
  71   // How close should the mouse be to the scrollbar before we thicken it.
  72   float mouse_move_distance_to_trigger_animation_;
  73
  74   DISALLOW_COPY_AND_ASSIGN(ScrollbarAnimationControllerThinning);
  75 };
  76
  77 }  // namespace cc
  78
  79 #endif  // CC_ANIMATION_SCROLLBAR_ANIMATION_CONTROLLER_THINNING_H_