void ScrollView::processAutoScrolling(float deltaTime)
{
// Make auto scroll shorter if it needs to deaccelerate.
float brakingFactor = (isNecessaryAutoScrollBrake() ? OUT_OF_BOUNDARY_BREAKING_FACTOR : 1);
// Elapsed time
_autoScrollAccumulatedTime += deltaTime * (1 / brakingFactor);
// Calculate the progress percentage
float percentage = MIN(1, _autoScrollAccumulatedTime / _autoScrollTotalTime);
if(_autoScrollAttenuate)
{
// Use quintic(5th degree) polynomial
percentage = tweenfunc::quintEaseOut(percentage);
}
// Calculate the new position
Vec2 newPosition = _autoScrollStartPosition + (_autoScrollTargetDelta * percentage);
bool reachedEnd = std::abs(percentage - 1) <= this->getAutoScrollStopEpsilon();
if (reachedEnd)
{
newPosition = _autoScrollStartPosition + _autoScrollTargetDelta;
}
if(_bounceEnabled)
{
// The new position is adjusted if out of boundary
newPosition = _autoScrollBrakingStartPosition + (newPosition - _autoScrollBrakingStartPosition) * brakingFactor;
}
else
{
// Don't let go out of boundary
Vec2 moveDelta = newPosition - getInnerContainerPosition();
Vec2 outOfBoundary = getHowMuchOutOfBoundary(moveDelta);
if (!fltEqualZero(outOfBoundary))
{
newPosition += outOfBoundary;
reachedEnd = true;
}
}
// Finish auto scroll if it ended
if(reachedEnd)
{
_autoScrolling = false;
dispatchEvent(SCROLLVIEW_EVENT_AUTOSCROLL_ENDED, EventType::AUTOSCROLL_ENDED);
}
moveInnerContainer(newPosition - getInnerContainerPosition(), reachedEnd);
}
void ScrollView::moveInnerContainer(const Vec2& deltaMove, bool canStartBounceBack)
{
Vec2 adjustedMove = flattenVectorByDirection(deltaMove);
setInnerContainerPosition(getInnerContainerPosition() + adjustedMove);
Vec2 outOfBoundary = getHowMuchOutOfBoundary();
updateScrollBar(outOfBoundary);
if(_bounceEnabled && canStartBounceBack)
{
startBounceBackIfNeeded();
}
}
void ListView::jumpToItem(ssize_t itemIndex, const Vec2& positionRatioInView, const Vec2& itemAnchorPoint)
{
Widget* item = getItem(itemIndex);
if (item == nullptr)
{
return;
}
doLayout();
Vec2 destination = calculateItemDestination(positionRatioInView, item, itemAnchorPoint);
if(!_bounceEnabled)
{
Vec2 delta = destination - getInnerContainerPosition();
Vec2 outOfBoundary = getHowMuchOutOfBoundary(delta);
destination += outOfBoundary;
}
jumpToDestination(destination);
}
bool ScrollView::isNecessaryAutoScrollBrake()
{
if(_autoScrollBraking)
{
return true;
}
if(isOutOfBoundary())
{
// It just went out of boundary.
if(!_autoScrollCurrentlyOutOfBoundary)
{
_autoScrollCurrentlyOutOfBoundary = true;
_autoScrollBraking = true;
_autoScrollBrakingStartPosition = getInnerContainerPosition();
return true;
}
}
else
{
_autoScrollCurrentlyOutOfBoundary = false;
}
return false;
}
void ScrollView::jumpToDestination(const Vec2 &des)
{
_autoScrolling = false;
moveInnerContainer(des - getInnerContainerPosition(), true);
}
float ScrollView::getScrolledPercentHorizontal() const {
const float minX = getContentSize().width - getInnerContainerSize().width;
return getInnerContainerPosition().x / minX * 100.f;
}
float ScrollView::getScrolledPercentVertical() const {
const float minY = getContentSize().height - getInnerContainerSize().height;
return (1.f - getInnerContainerPosition().y / minY)*100.f;
}