cc/scrollbar_animation_controller_linear_fade.cc

   1 // Copyright 2012 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/scrollbar_animation_controller_linear_fade.h"
   6
   7 #include "cc/scrollbar_layer_impl.h"
   8
   9 namespace cc {
  10
  11 scoped_ptr<ScrollbarAnimationControllerLinearFade> ScrollbarAnimationControllerLinearFade::create(LayerImpl* scrollLayer, double fadeoutDelay, double fadeoutLength)
  12 {
  13     return make_scoped_ptr(new ScrollbarAnimationControllerLinearFade(scrollLayer, fadeoutDelay, fadeoutLength));
  14 }
  15
  16 ScrollbarAnimationControllerLinearFade::ScrollbarAnimationControllerLinearFade(LayerImpl* scrollLayer, double fadeoutDelay, double fadeoutLength)
  17     : ScrollbarAnimationController(scrollLayer)
  18     , m_lastAwakenTime(-100000000) // arbitrary invalid timestamp
  19     , m_pinchGestureInEffect(false)
  20     , m_fadeoutDelay(fadeoutDelay)
  21     , m_fadeoutLength(fadeoutLength)
  22 {
  23 }
  24
  25 ScrollbarAnimationControllerLinearFade::~ScrollbarAnimationControllerLinearFade()
  26 {
  27 }
  28
  29 bool ScrollbarAnimationControllerLinearFade::animate(double monotonicTime)
  30 {
  31     float opacity = opacityAtTime(monotonicTime);
  32     if (horizontalScrollbarLayer())
  33         horizontalScrollbarLayer()->setOpacity(opacity);
  34     if (verticalScrollbarLayer())
  35         verticalScrollbarLayer()->setOpacity(opacity);
  36     return opacity;
  37 }
  38
  39 void ScrollbarAnimationControllerLinearFade::didPinchGestureUpdateAtTime(double)
  40 {
  41     m_pinchGestureInEffect = true;
  42 }
  43
  44 void ScrollbarAnimationControllerLinearFade::didPinchGestureEndAtTime(double monotonicTime)
  45 {
  46     m_pinchGestureInEffect = false;
  47     m_lastAwakenTime = monotonicTime;
  48 }
  49
  50 void ScrollbarAnimationControllerLinearFade::updateScrollOffsetAtTime(LayerImpl* scrollLayer, double monotonicTime)
  51 {
  52     gfx::Vector2dF previousPos = currentOffset();
  53     ScrollbarAnimationController::updateScrollOffsetAtTime(scrollLayer, monotonicTime);
  54
  55     if (previousPos == currentOffset())
  56         return;
  57
  58     m_lastAwakenTime = monotonicTime;
  59 }
  60
  61 float ScrollbarAnimationControllerLinearFade::opacityAtTime(double monotonicTime)
  62 {
  63     if (m_pinchGestureInEffect)
  64         return 1;
  65
  66     double delta = monotonicTime - m_lastAwakenTime;
  67
  68     if (delta <= m_fadeoutDelay)
  69         return 1;
  70     if (delta < m_fadeoutDelay + m_fadeoutLength)
  71         return (m_fadeoutDelay + m_fadeoutLength - delta) / m_fadeoutLength;
  72     return 0;
  73 }
  74
  75 }  // namespace cc