New function: scrollToElement

[waldbaerkoch]

Hi,

you may want to add a new public function: scrollToElement, adapted from _childFocused:

var scrollToElement = function scrollToElement(element, animationDuration) {
    var offset, axis;
    var focusedNodeRect = _getBoundingRect(element);
    var containerRect = _getBoundingRect(_containerNode);
    var edgeMap = { x: 'left', y: 'top' };
    var dimensionMap = { x: 'width', y: 'height' };

    // If an input is currently being tracked, ignore the focus event
    if (_inputIdentifier !== false) {
        return;
    }

    // Get a duration
    var duration = animationDuration || 0;
    if (duration === true) {
        duration = Math.sqrt(Math.abs(_baseScrollPosition[axis] - targetPosition)) * 20;
    }
    for (axis in _scrollableAxes) {
        if (_scrollableAxes.hasOwnProperty(axis)) {

            // Set the target offset to be in the middle of the container, or as close as bounds permit
            offset = -Math.round((focusedNodeRect[dimensionMap[axis]] / 2) - _lastScrollPosition[axis] + focusedNodeRect[edgeMap[axis]] - containerRect[edgeMap[axis]]  - (containerRect[dimensionMap[axis]] / 2));
            offset = Math.min(0, Math.max(_metrics.scrollEnd[axis], offset));

            // Perform the scroll
            _setAxisPosition(axis, offset, duration);
            _baseScrollPosition[axis] = offset;
        }
    }
};

_childFocused can then call this new function.