bool ScrollAnimationSmooth::animateScroll(PerAxisData& data, double currentTime)
{
if (!data.startTime)
return false;
double lastScrollInterval = currentTime - data.lastAnimationTime;
if (lastScrollInterval < minimumTimerInterval)
return true;
data.lastAnimationTime = currentTime;
double deltaTime = currentTime - data.startTime;
double newPosition = data.currentPosition;
if (deltaTime > data.animationTime) {
data = PerAxisData(data.desiredPosition, data.visibleLength);
return false;
}
if (deltaTime < data.attackTime)
newPosition = attackCurve(Curve::Cubic, deltaTime, data.attackTime, data.startPosition, data.attackPosition);
else if (deltaTime < (data.animationTime - data.releaseTime))
newPosition = data.attackPosition + (deltaTime - data.attackTime) * data.desiredVelocity;
else {
// release is based on targeting the exact final position.
double releaseDeltaT = deltaTime - (data.animationTime - data.releaseTime);
newPosition = releaseCurve(Curve::Cubic, releaseDeltaT, data.releaseTime, data.releasePosition, data.desiredPosition);
}
// Normalize velocity to a per second amount. Could be used to check for jank.
if (lastScrollInterval > 0)
data.currentVelocity = (newPosition - data.currentPosition) / lastScrollInterval;
data.currentPosition = newPosition;
return true;
}
// FIXME: Add in jank detection trace events into this function.
bool ScrollAnimatorNone::PerAxisData::animateScroll(double currentTime)
{
double lastScrollInterval = currentTime - m_lastAnimationTime;
if (lastScrollInterval < kMinimumTimerInterval)
return true;
m_lastAnimationTime = currentTime;
double deltaTime = currentTime - m_startTime;
double newPosition = *m_currentPosition;
if (deltaTime > m_animationTime) {
*m_currentPosition = m_desiredPosition;
reset();
return false;
}
if (deltaTime < m_attackTime)
newPosition = attackCurve(m_attackCurve, deltaTime, m_attackTime, m_startPosition, m_attackPosition);
else if (deltaTime < (m_animationTime - m_releaseTime))
newPosition = m_attackPosition + (deltaTime - m_attackTime) * m_desiredVelocity;
else {
// release is based on targeting the exact final position.
double releaseDeltaT = deltaTime - (m_animationTime - m_releaseTime);
newPosition = releaseCurve(m_releaseCurve, releaseDeltaT, m_releaseTime, m_releasePosition, m_desiredPosition);
}
// Normalize velocity to a per second amount. Could be used to check for jank.
if (lastScrollInterval > 0)
m_currentVelocity = (newPosition - *m_currentPosition) / lastScrollInterval;
*m_currentPosition = newPosition;
return true;
}
inline double ScrollAnimator::PerAxisData::newScrollAnimationPosition(double deltaTime)
{
if (deltaTime < m_attackTime)
return attackCurve(m_attackCurve, deltaTime, m_attackTime, m_startPosition, m_attackPosition);
if (deltaTime < (m_animationTime - m_releaseTime))
return m_attackPosition + (deltaTime - m_attackTime) * m_desiredVelocity;
// release is based on targeting the exact final position.
double releaseDeltaT = deltaTime - (m_animationTime - m_releaseTime);
return releaseCurve(m_releaseCurve, releaseDeltaT, m_releaseTime, m_releasePosition, m_desiredPosition);
}