Code (Javascript)

function diagramView_OnNodeMove(sender, args) {

    var nodePosition = args.node.getBounds();

    var margin = nodePosition.width;

    var diagramView = sender._element;

    const increment = 25;
    var bounds = getDiagramBounds();
    var left = bounds.left()
    var right = bounds.right();
    var top = bounds.top();
    var bottom = bounds.bottom();

    if (nodePosition.x <= left) {
        left -= increment;
        setDiagramBounds(left, top, right, bottom);
    }
    else if (nodePosition.x >= right - margin) {
        right += increment;
        setDiagramBounds(left, top, right, bottom);
        sender.setScrollX(sender.getScrollX() + increment);
    }
    else if (nodePosition.y <= top) {
        top -= increment;
        setDiagramBounds(left, top, right, bottom);
    }
    else if (nodePosition.y >= bottom - margin) {
        bottom += increment;
        setDiagramBounds(left, top, right, bottom);
        sender.setScrollY(sender.getScrollY() + increment);
    }
}