void ScrollAnimationSmooth::setCurrentPosition(const FloatPoint& position)
{
stop();
m_horizontalData = PerAxisData();
m_horizontalData.currentPosition = position.x();
m_horizontalData.desiredPosition = m_horizontalData.currentPosition;
m_verticalData = PerAxisData();
m_verticalData.currentPosition = position.y();
m_verticalData.desiredPosition = m_verticalData.currentPosition;
}
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;
}
void ScrollAnimationSmooth::setCurrentPosition(const FloatPoint& position)
{
stop();
m_horizontalData = PerAxisData(position.x(), m_horizontalData.visibleLength);
m_verticalData = PerAxisData(position.y(), m_verticalData.visibleLength);
}
