scroll.js

(function ($) { //needs drop to determine if respondable
  $.Drag.prototype.

  scrolls = function (elements, options) {
    var elements = $(elements);

    for (var i = 0; i < elements.length; i++) {
      this.constructor.responder._elements.push(elements.eq(i).data("_dropData", new $.Scrollable(elements[i], options))[0])
    }
  },

  $.Scrollable = function (element, options) {
    this.element = jQuery(element);
    this.options = $.extend({

      distance: 30,

      delta: function (diff, distance) {
        return (distance - diff) / 2;
      },
      direction: "xy"
    }, options);
    this.x = this.options.direction.indexOf("x") != -1;
    this.y = this.options.direction.indexOf("y") != -1;
  }
  $.extend($.Scrollable.prototype, {
    init: function (element) {
      this.element = jQuery(element);
    },
    callHandlers: function (method, el, ev, drag) {
      this[method](el || this.element[0], ev, this, drag)
    },
    dropover: function () {

    },
    dropon: function () {
      this.clear_timeout();
    },
    dropout: function () {
      this.clear_timeout();
    },
    dropinit: function () {

    },
    dropend: function () {},
    clear_timeout: function () {
      if (this.interval) {
        clearTimeout(this.interval)
        this.interval = null;
      }
    },
    distance: function (diff) {
      return (30 - diff) / 2;
    },
    dropmove: function (el, ev, drop, drag) {

      this.clear_timeout();

      var mouse = ev.vector(),

        location_object = $(el == document.documentElement ? window : el),

        dimensions = location_object.dimensionsv('outer'),
        position = location_object.offsetv(),

        bottom = position.y() + dimensions.y() - mouse.y(),
        top = mouse.y() - position.y(),
        right = position.x() + dimensions.x() - mouse.x(),
        left = mouse.x() - position.x(),

        dx = 0,
        dy = 0,
        distance = this.options.distance;

      if (bottom < distance && this.y) {
        dy = this.options.delta(bottom, distance);
      } else if (top < distance && this.y) {
        dy = -this.options.delta(top, distance);
      }

      if (right < distance && this.options && this.x) {
        dx = this.options.delta(right, distance);
      } else if (left < distance && this.x) {
        dx = -this.options.delta(left, distance);
      }

      if (dx || dy) {

        var self = this;
        this.interval = setTimeout(function () {
          self.move($(el), drag.movingElement, dx, dy, ev, ev.clientX, ev.clientY, ev.screenX, ev.screenY)
        }, 15)
      }
    },

    move: function (scroll_element, drag_element, dx, dy, ev) {
      scroll_element.scrollTop(scroll_element.scrollTop() + dy);
      scroll_element.scrollLeft(scroll_element.scrollLeft() + dx);

      drag_element.trigger(
      $.event.fix({
        type: "mousemove",
        clientX: ev.clientX,
        clientY: ev.clientY,
        screenX: ev.screenX,
        screenY: ev.screenY,
        pageX: ev.pageX,
        pageY: ev.pageY
      }))

    }
  })

  return $;
})(jQuery);