Function wrapAnimator

scrollability.js:180–577

(animator, startX, startY, startTime)

}

function wrapAnimator(animator, startX, startY, startTime) {
    var node = animator.node;
    var constrained = animator.constrained;
    var paginated = animator.paginated;
    var viewport = animator.viewport || 0;
    var scrollbar = animator.scrollbar;
    var position = animator.position;
    var min = animator.min;
    var max = animator.max;
    var absMin = min;
    var absMax = Math.round(max/viewport)*viewport;
    var pageSpacing = 0;
    var velocity = 0;
    var bounceTime = paginated ? kPageBounceTime : kBounceTime;
    var bounceLimit = animator.bounce;
    var pageLimit = viewport * kPageLimit;
    var lastTouch = startTouch = animator.filter(startX, startY);
    var lastTime = startTime;
    var timeStep = 0;
    var stopped = 0;
    var tracked = [];
    var offset = node.scrollableOffset||0;

    if (!animator.mute) {
        var event = {
            position: position,
            min: min,
            max: max,
            track: addTracker,
            setSpacing: setSpacing,
            setOffset: setOffset,
            setBounds: setBounds
        };
        if (!dispatch("scrollability-start", node, event)) {
            return null;
        }
    }

    if (paginated) {
        if (pageSpacing === undefined) {
            var excess = Math.round(Math.abs(absMin) % viewport);
            var pageCount = ((Math.abs(absMin)-excess) / viewport)+1;
            pageSpacing = excess / pageCount;
        }

        var pageIndex = Math.round(position/(viewport+pageSpacing));
        min = max = pageIndex * (viewport+pageSpacing);
        absMin += pageSpacing;
    }

    if (scrollbar) {
        addTracker(scrollbar, trackScrollbar);
        if (!scrollbar.parentNode) {
            node.parentNode.appendChild(scrollbar);            
        }
    }

    if (node.earlyEnd) {