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      1 // Copyright 2014 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 "config.h"
      6 #include "platform/scroll/ProgrammaticScrollAnimator.h"
      7 
      8 #include "platform/geometry/IntPoint.h"
      9 #include "platform/scroll/ScrollableArea.h"
     10 #include "public/platform/Platform.h"
     11 #include "public/platform/WebCompositorSupport.h"
     12 #include "public/platform/WebScrollOffsetAnimationCurve.h"
     13 
     14 namespace blink {
     15 
     16 PassOwnPtr<ProgrammaticScrollAnimator> ProgrammaticScrollAnimator::create(ScrollableArea* scrollableArea)
     17 {
     18     return adoptPtr(new ProgrammaticScrollAnimator(scrollableArea));
     19 }
     20 
     21 ProgrammaticScrollAnimator::ProgrammaticScrollAnimator(ScrollableArea* scrollableArea)
     22     : m_scrollableArea(scrollableArea)
     23     , m_startTime(0.0)
     24 {
     25 }
     26 
     27 ProgrammaticScrollAnimator::~ProgrammaticScrollAnimator()
     28 {
     29 }
     30 
     31 void ProgrammaticScrollAnimator::resetAnimationState()
     32 {
     33     m_animationCurve.clear();
     34     m_startTime = 0.0;
     35 }
     36 
     37 void ProgrammaticScrollAnimator::animateToOffset(FloatPoint offset)
     38 {
     39     m_startTime = 0.0;
     40     m_targetOffset = offset;
     41     m_animationCurve = adoptPtr(Platform::current()->compositorSupport()->createScrollOffsetAnimationCurve(m_targetOffset, WebCompositorAnimationCurve::TimingFunctionTypeEaseInOut));
     42 
     43     m_animationCurve->setInitialValue(FloatPoint(m_scrollableArea->scrollPosition()));
     44     if (!m_scrollableArea->scheduleAnimation()) {
     45         resetAnimationState();
     46         m_scrollableArea->notifyScrollPositionChanged(IntPoint(offset.x(), offset.y()));
     47     }
     48 }
     49 
     50 void ProgrammaticScrollAnimator::cancelAnimation()
     51 {
     52     resetAnimationState();
     53 }
     54 
     55 void ProgrammaticScrollAnimator::tickAnimation(double monotonicTime)
     56 {
     57     if (m_animationCurve) {
     58         if (!m_startTime)
     59             m_startTime = monotonicTime;
     60         double elapsedTime = monotonicTime - m_startTime;
     61         bool isFinished = (elapsedTime > m_animationCurve->duration());
     62         FloatPoint offset = m_animationCurve->getValue(elapsedTime);
     63         m_scrollableArea->notifyScrollPositionChanged(IntPoint(offset.x(), offset.y()));
     64 
     65         if (isFinished) {
     66             resetAnimationState();
     67         } else if (!m_scrollableArea->scheduleAnimation()) {
     68             m_scrollableArea->notifyScrollPositionChanged(IntPoint(m_targetOffset.x(), m_targetOffset.y()));
     69             resetAnimationState();
     70         }
     71     }
     72 }
     73 
     74 } // namespace blink
     75