Function f

client/utils/dragdrop.js:183–216

(e)

                if (options.start) options.start();

                var f = function(e) {
                    var _drop = that.getDrop();

                    dx = oX - e.pageX;
                    dy = oY - e.pageY;

                    if (Math.abs(dx) > 20 || Math.abs(dy) > 20) {
                        if (!hasMove) {
                            setCursor(options.cursor);
                            $el.addClass("move");
                        }
                        hasMove = true;
                    }

                    ex = poX - dx;
                    ey = poY - dy;

                    if (_drop && _drop.options.constrain) {
                        cw = _drop.$el.width();
                        ch = _drop.$el.height();
                        cx = _drop.$el.offset().left;
                        cy = _drop.$el.offset().top;

                        if (Math.abs(ey - cy) < 50) ey = cy;
                        if (Math.abs((ey + eh) - (cy+ch)) < 50) ey = cy + ch - eh;
                        if (Math.abs(ex - cx) < 50) ex = cx;
                        if (Math.abs((ex + ew) - (cx+cw)) < 50) ex = cx + cw - ew;
                    }

                    $el.css({
                        'left': ex,
                        'top': ey
                    });
                };

                $document.on(events["move"], f);
                $document.one(events["stop"], function(e) {