jquery-ui/ui/ui.draggable.js

/*
 * jQuery UI Draggable @VERSION
 *
 * Copyright (c) 2008 AUTHORS.txt (http://ui.jquery.com/about)
 * Dual licensed under the MIT (MIT-LICENSE.txt)
 * and GPL (GPL-LICENSE.txt) licenses.
 *
 * http://docs.jquery.com/UI/Draggables
 *
 * Depends:
 *	ui.core.js
 */
(function($) {

$.widget("ui.draggable", $.extend({}, $.ui.mouse, {

	_init: function() {

		if (this.options.helper == 'original' && !(/^(?:r|a|f)/).test(this.element.css("position")))
			this.element[0].style.position = 'relative';

		(this.options.cssNamespace && this.element.addClass(this.options.cssNamespace+"-draggable"));
		(this.options.disabled && this.element.addClass('ui-draggable-disabled'));

		this._mouseInit();

	},

	destroy: function() {
		if(!this.element.data('draggable')) return;
		this.element.removeData("draggable").unbind(".draggable").removeClass('ui-draggable ui-draggable-dragging ui-draggable-disabled');
		this._mouseDestroy();
	},

	_mouseCapture: function(event) {

		var o = this.options;

		if (this.helper || o.disabled || $(event.target).is('.ui-resizable-handle'))
			return false;

		//Quit if we're not on a valid handle
		this.handle = this._getHandle(event);
		if (!this.handle)
			return false;

		return true;

	},

	_mouseStart: function(event) {

		var o = this.options;

		//Create and append the visible helper
		this.helper = this._createHelper(event);

		//Cache the helper size
		this._cacheHelperProportions();

		//If ddmanager is used for droppables, set the global draggable
		if($.ui.ddmanager)
			$.ui.ddmanager.current = this;

		/*
		 * - Position generation -
		 * This block generates everything position related - it's the core of draggables.
		 */

		//Cache the margins of the original element
		this._cacheMargins();

		//Store the helper's css position
		this.cssPosition = this.helper.css("position");
		this.scrollParent = this.helper.scrollParent();

		//The element's absolute position on the page minus margins
		this.offset = this.element.offset();
		this.offset = {
			top: this.offset.top - this.margins.top,
			left: this.offset.left - this.margins.left
		};

		$.extend(this.offset, {
			click: { //Where the click happened, relative to the element
				left: event.pageX - this.offset.left,
				top: event.pageY - this.offset.top
			},
			parent: this._getParentOffset(),
			relative: this._getRelativeOffset() //This is a relative to absolute position minus the actual position calculation - only used for relative positioned helper
		});

		//Adjust the mouse offset relative to the helper if 'cursorAt' is supplied
		if(o.cursorAt)
			this._adjustOffsetFromHelper(o.cursorAt);

		//Generate the original position
		this.originalPosition = this._generatePosition(event);

		//Set a containment if given in the options
		if(o.containment)
			this._setContainment();

		//Call plugins and callbacks
		this._propagate("start", event);

		//Recache the helper size
		this._cacheHelperProportions();

		//Prepare the droppable offsets
		if ($.ui.ddmanager && !o.dropBehaviour)
			$.ui.ddmanager.prepareOffsets(this, event);

		this.helper.addClass("ui-draggable-dragging");
		this._mouseDrag(event, true); //Execute the drag once - this causes the helper not to be visible before getting its correct position
		return true;
	},

	_mouseDrag: function(event, noPropagation) {

		//Compute the helpers position
		this.position = this._generatePosition(event);
		this.positionAbs = this._convertPositionTo("absolute");

		//Call plugins and callbacks and use the resulting position if something is returned
		if(!noPropagation) this.position = this._propagate("drag", event) || this.position;

		if(!this.options.axis || this.options.axis != "y") this.helper[0].style.left = this.position.left+'px';
		if(!this.options.axis || this.options.axis != "x") this.helper[0].style.top = this.position.top+'px';
		if($.ui.ddmanager) $.ui.ddmanager.drag(this, event);

		return false;
	},

	_mouseStop: function(event) {

		//If we are using droppables, inform the manager about the drop
		var dropped = false;
		if ($.ui.ddmanager && !this.options.dropBehaviour)
			var dropped = $.ui.ddmanager.drop(this, event);

		if((this.options.revert == "invalid" && !dropped) || (this.options.revert == "valid" && dropped) || this.options.revert === true || ($.isFunction(this.options.revert) && this.options.revert.call(this.element, dropped))) {
			var self = this;
			$(this.helper).animate(this.originalPosition, parseInt(this.options.revertDuration, 10), function() {
				self._propagate("stop", event);
				self._clear();
			});
		} else {
			this._propagate("stop", event);
			this._clear();
		}

		return false;
	},

	_getHandle: function(event) {

		var handle = !this.options.handle || !$(this.options.handle, this.element).length ? true : false;
		$(this.options.handle, this.element)
			.find("*")
			.andSelf()
			.each(function() {
				if(this == event.target) handle = true;
			});

		return handle;

	},

	_createHelper: function(event) {

		var o = this.options;
		var helper = $.isFunction(o.helper) ? $(o.helper.apply(this.element[0], [event])) : (o.helper == 'clone' ? this.element.clone() : this.element);

		if(!helper.parents('body').length)
			helper.appendTo((o.appendTo == 'parent' ? this.element[0].parentNode : o.appendTo));

		if(helper[0] != this.element[0] && !(/(fixed|absolute)/).test(helper.css("position")))
			helper.css("position", "absolute");

		return helper;

	},

	_adjustOffsetFromHelper: function(obj) {
		if(obj.left != undefined) this.offset.click.left = obj.left + this.margins.left;
		if(obj.right != undefined) this.offset.click.left = this.helperProportions.width - obj.right + this.margins.left;
		if(obj.top != undefined) this.offset.click.top = obj.top + this.margins.top;
		if(obj.bottom != undefined) this.offset.click.top = this.helperProportions.height - obj.bottom + this.margins.top;
	},

	_getParentOffset: function() {

		this.offsetParent = this.helper.offsetParent(); var po = this.offsetParent.offset();			//Get the offsetParent and cache its position

		if((this.offsetParent[0] == document.body && $.browser.mozilla)	//Ugly FF3 fix
		|| (this.offsetParent[0].tagName && this.offsetParent[0].tagName.toLowerCase() == 'html' && $.browser.msie)) //Ugly IE fix
			po = { top: 0, left: 0 };

		return {
			top: po.top + (parseInt(this.offsetParent.css("borderTopWidth"),10) || 0),
			left: po.left + (parseInt(this.offsetParent.css("borderLeftWidth"),10) || 0)
		};

	},

	_getRelativeOffset: function() {

		if(this.cssPosition == "relative") {
			var p = this.element.position();
			return {
				top: p.top - (parseInt(this.helper.css("top"),10) || 0) + this.scrollParent.scrollTop(),
				left: p.left - (parseInt(this.helper.css("left"),10) || 0) + this.scrollParent.scrollLeft()
			};
		} else {
			return { top: 0, left: 0 };
		}

	},

	_cacheMargins: function() {
		this.margins = {
			left: (parseInt(this.element.css("marginLeft"),10) || 0),
			top: (parseInt(this.element.css("marginTop"),10) || 0)
		};
	},

	_cacheHelperProportions: function() {
		this.helperProportions = {
			width: this.helper.outerWidth(),
			height: this.helper.outerHeight()
		};
	},

	_setContainment: function() {

		var o = this.options;
		if(o.containment == 'parent') o.containment = this.helper[0].parentNode;
		if(o.containment == 'document' || o.containment == 'window') this.containment = [
			0 - this.offset.relative.left - this.offset.parent.left,
			0 - this.offset.relative.top - this.offset.parent.top,
			$(o.containment == 'document' ? document : window).width() - this.offset.relative.left - this.offset.parent.left - this.helperProportions.width - this.margins.left - (parseInt(this.element.css("marginRight"),10) || 0),
			($(o.containment == 'document' ? document : window).height() || document.body.parentNode.scrollHeight) - this.offset.relative.top - this.offset.parent.top - this.helperProportions.height - this.margins.top - (parseInt(this.element.css("marginBottom"),10) || 0)
		];

		if(!(/^(document|window|parent)$/).test(o.containment)) {
			var ce = $(o.containment)[0];
			var co = $(o.containment).offset();
			var over = ($(ce).css("overflow") != 'hidden');

			this.containment = [
				co.left + (parseInt($(ce).css("borderLeftWidth"),10) || 0) - this.offset.relative.left - this.offset.parent.left,
				co.top + (parseInt($(ce).css("borderTopWidth"),10) || 0) - this.offset.relative.top - this.offset.parent.top,
				co.left+(over ? Math.max(ce.scrollWidth,ce.offsetWidth) : ce.offsetWidth) - (parseInt($(ce).css("borderLeftWidth"),10) || 0) - this.offset.relative.left - this.offset.parent.left - this.helperProportions.width - this.margins.left - (parseInt(this.element.css("marginRight"),10) || 0),
				co.top+(over ? Math.max(ce.scrollHeight,ce.offsetHeight) : ce.offsetHeight) - (parseInt($(ce).css("borderTopWidth"),10) || 0) - this.offset.relative.top - this.offset.parent.top - this.helperProportions.height - this.margins.top - (parseInt(this.element.css("marginBottom"),10) || 0)
			];
		}

	},

	_convertPositionTo: function(d, pos) {

		if(!pos) pos = this.position;
		var mod = d == "absolute" ? 1 : -1;
		var scroll = this[(this.cssPosition == 'absolute' ? 'offset' : 'scroll')+'Parent'], scrollIsRootNode = (/(html|body)/i).test(scroll[0].tagName);

		return {
			top: (
				pos.top																	// the calculated relative position
				+ this.offset.relative.top	* mod										// Only for relative positioned nodes: Relative offset from element to offset parent
				+ this.offset.parent.top * mod											// The offsetParent's offset without borders (offset + border)
				+ ( this.cssPosition == 'fixed' ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : scroll.scrollTop() ) ) * mod
				+ this.margins.top * mod												//Add the margin (you don't want the margin counting in intersection methods)
			),
			left: (
				pos.left																// the calculated relative position
				+ this.offset.relative.left	* mod										// Only for relative positioned nodes: Relative offset from element to offset parent
				+ this.offset.parent.left * mod											// The offsetParent's offset without borders (offset + border)
				+ ( this.cssPosition == 'fixed' ? -this.scrollParent.scrollLeft() : ( scrollIsRootNode ? 0 : scroll.scrollLeft() ) ) * mod
				+ this.margins.left * mod												//Add the margin (you don't want the margin counting in intersection methods)
			)
		};
	},

	_generatePosition: function(event) {

		var o = this.options, scroll = this[(this.cssPosition == 'absolute' ? 'offset' : 'scroll')+'Parent'], scrollIsRootNode = (/(html|body)/i).test(scroll[0].tagName);

		var position = {
			top: (
				event.pageY																// The absolute mouse position
				- this.offset.click.top													// Click offset (relative to the element)
				- this.offset.relative.top												// Only for relative positioned nodes: Relative offset from element to offset parent
				- this.offset.parent.top												// The offsetParent's offset without borders (offset + border)
				+ ( this.cssPosition == 'fixed' ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : scroll.scrollTop() ) )
			),
			left: (
				event.pageX																// The absolute mouse position
				- this.offset.click.left												// Click offset (relative to the element)
				- this.offset.relative.left												// Only for relative positioned nodes: Relative offset from element to offset parent
				- this.offset.parent.left												// The offsetParent's offset without borders (offset + border)
				+ ( this.cssPosition == 'fixed' ? -this.scrollParent.scrollLeft() : scrollIsRootNode ? 0 : scroll.scrollLeft() )
			)
		};

		if(!this.originalPosition) return position;										//If we are not dragging yet, we won't check for options

		/*
		 * - Position constraining -
		 * Constrain the position to a mix of grid, containment.
		 */
		if(this.containment) {
			if(position.left < this.containment[0]) position.left = this.containment[0];
			if(position.top < this.containment[1]) position.top = this.containment[1];
			if(position.left > this.containment[2]) position.left = this.containment[2];
			if(position.top > this.containment[3]) position.top = this.containment[3];
		}

		if(o.grid) {
			var top = this.originalPosition.top + Math.round((position.top - this.originalPosition.top) / o.grid[1]) * o.grid[1];
			position.top = this.containment ? (!(top < this.containment[1] || top > this.containment[3]) ? top : (!(top < this.containment[1]) ? top - o.grid[1] : top + o.grid[1])) : top;

			var left = this.originalPosition.left + Math.round((position.left - this.originalPosition.left) / o.grid[0]) * o.grid[0];
			position.left = this.containment ? (!(left < this.containment[0] || left > this.containment[2]) ? left : (!(left < this.containment[0]) ? left - o.grid[0] : left + o.grid[0])) : left;
		}

		return position;
	},

	_clear: function() {
		this.helper.removeClass("ui-draggable-dragging");
		if(this.helper[0] != this.element[0] && !this.cancelHelperRemoval) this.helper.remove();
		//if($.ui.ddmanager) $.ui.ddmanager.current = null;
		this.helper = null;
		this.cancelHelperRemoval = false;
	},

	// From now on bulk stuff - mainly helpers

	_propagate: function(n, event) {
		$.ui.plugin.call(this, n, [event, this._uiHash()]);
		if(n == "drag") this.positionAbs = this._convertPositionTo("absolute"); //The absolute position has to be recalculated after plugins
		return this.element.triggerHandler(n == "drag" ? n : "drag"+n, [event, this._uiHash()], this.options[n]);
	},

	plugins: {},

	_uiHash: function(event) {
		return {
			helper: this.helper,
			position: this.position,
			absolutePosition: this.positionAbs,
			options: this.options
		};
	}

}));

$.extend($.ui.draggable, {
	version: "@VERSION",
	defaults: {
		appendTo: "parent",
		axis: false,
		cancel: ":input",
		connectToSortable: false,
		containment: false,
		cssNamespace: "ui",
		cursor: "default",
		cursorAt: null,
		delay: 0,
		distance: 1,
		grid: false,
		handle: false,
		helper: "original",
		iframeFix: false,
		opacity: 1,
		refreshPositions: false,
		revert: false,
		revertDuration: 500,
		scope: "default",
		scroll: false,
		scrollSensitivity: 20,
		scrollSpeed: 20,
		snap: false,
		snapMode: "both",
		snapTolerance: 20,
		stack: false,
		zIndex: null
	}
});

$.ui.plugin.add("draggable", "connectToSortable", {
	start: function(event, ui) {

		var inst = $(this).data("draggable");
		inst.sortables = [];
		$(ui.options.connectToSortable).each(function() {
			// 'this' points to a string, and should therefore resolved as query, but instead, if the string is assigned to a variable, it loops through the strings properties,
			// so we have to append '' to make it anonymous again
			$(this+'').each(function() {
				if($.data(this, 'sortable')) {
					var sortable = $.data(this, 'sortable');
					inst.sortables.push({
						instance: sortable,
						shouldRevert: sortable.options.revert
					});
					sortable._refreshItems();	//Do a one-time refresh at start to refresh the containerCache
					sortable._propagate("activate", event, inst);
				}
			});
		});

	},
	stop: function(event, ui) {

		//If we are still over the sortable, we fake the stop event of the sortable, but also remove helper
		var inst = $(this).data("draggable");

		$.each(inst.sortables, function() {
			if(this.instance.isOver) {
				this.instance.isOver = 0;
				inst.cancelHelperRemoval = true; //Don't remove the helper in the draggable instance
				this.instance.cancelHelperRemoval = false; //Remove it in the sortable instance (so sortable plugins like revert still work)
				if(this.shouldRevert) this.instance.options.revert = true; //revert here
				this.instance._mouseStop(event);

				//Also propagate receive event, since the sortable is actually receiving a element
				this.instance.element.triggerHandler("sortreceive", [event, $.extend(this.instance._ui(), { sender: inst.element })], this.instance.options["receive"]);

				this.instance.options.helper = this.instance.options._helper;
			} else {
				this.instance.cancelHelperRemoval = false; //Remove the helper in the sortable instance
				this.instance._propagate("deactivate", event, inst);
			}

		});

	},
	drag: function(event, ui) {

		var inst = $(this).data("draggable"), self = this;

		var checkPos = function(o) {
			var dyClick = this.offset.click.top, dxClick = this.offset.click.left;
			var helperTop = this.positionAbs.top, helperLeft = this.positionAbs.left;
			var itemHeight = o.height, itemWidth = o.width;
			var itemTop = o.top, itemLeft = o.left;

			return $.ui.isOver(helperTop + dyClick, helperLeft + dxClick, itemTop, itemLeft, itemHeight, itemWidth);
		};

		$.each(inst.sortables, function(i) {

			if(checkPos.call(inst, this.instance.containerCache)) {

				//If it intersects, we use a little isOver variable and set it once, so our move-in stuff gets fired only once
				if(!this.instance.isOver) {
					this.instance.isOver = 1;
					//Now we fake the start of dragging for the sortable instance,
					//by cloning the list group item, appending it to the sortable and using it as inst.currentItem
					//We can then fire the start event of the sortable with our passed browser event, and our own helper (so it doesn't create a new one)
					this.instance.currentItem = $(self).clone().appendTo(this.instance.element).data("sortable-item", true);
					this.instance.options._helper = this.instance.options.helper; //Store helper option to later restore it
					this.instance.options.helper = function() { return ui.helper[0]; };

					event.target = this.instance.currentItem[0];
					this.instance._mouseCapture(event, true);
					this.instance._mouseStart(event, true, true);

					//Because the browser event is way off the new appended portlet, we modify a couple of variables to reflect the changes
					this.instance.offset.click.top = inst.offset.click.top;
					this.instance.offset.click.left = inst.offset.click.left;
					this.instance.offset.parent.left -= inst.offset.parent.left - this.instance.offset.parent.left;
					this.instance.offset.parent.top -= inst.offset.parent.top - this.instance.offset.parent.top;

					inst._propagate("toSortable", event);

				}

				//Provided we did all the previous steps, we can fire the drag event of the sortable on every draggable drag, when it intersects with the sortable
				if(this.instance.currentItem) this.instance._mouseDrag(event);

			} else {

				//If it doesn't intersect with the sortable, and it intersected before,
				//we fake the drag stop of the sortable, but make sure it doesn't remove the helper by using cancelHelperRemoval
				if(this.instance.isOver) {
					this.instance.isOver = 0;
					this.instance.cancelHelperRemoval = true;
					this.instance.options.revert = false; //No revert here
					this.instance._mouseStop(event, true);
					this.instance.options.helper = this.instance.options._helper;

					//Now we remove our currentItem, the list group clone again, and the placeholder, and animate the helper back to it's original size
					this.instance.currentItem.remove();
					if(this.instance.placeholder) this.instance.placeholder.remove();

					inst._propagate("fromSortable", event);
				}

			};

		});

	}
});

$.ui.plugin.add("draggable", "cursor", {
	start: function(event, ui) {
		var t = $('body');
		if (t.css("cursor")) ui.options._cursor = t.css("cursor");
		t.css("cursor", ui.options.cursor);
	},
	stop: function(event, ui) {
		if (ui.options._cursor) $('body').css("cursor", ui.options._cursor);
	}
});

$.ui.plugin.add("draggable", "iframeFix", {
	start: function(event, ui) {
		$(ui.options.iframeFix === true ? "iframe" : ui.options.iframeFix).each(function() {
			$('<div class="ui-draggable-iframeFix" style="background: #fff;"></div>')
			.css({
				width: this.offsetWidth+"px", height: this.offsetHeight+"px",
				position: "absolute", opacity: "0.001", zIndex: 1000
			})
			.css($(this).offset())
			.appendTo("body");
		});
	},
	stop: function(event, ui) {
		$("div.ui-draggable-iframeFix").each(function() { this.parentNode.removeChild(this); }); //Remove frame helpers
	}
});

$.ui.plugin.add("draggable", "opacity", {
	start: function(event, ui) {
		var t = $(ui.helper);
		if(t.css("opacity")) ui.options._opacity = t.css("opacity");
		t.css('opacity', ui.options.opacity);
	},
	stop: function(event, ui) {
		if(ui.options._opacity) $(ui.helper).css('opacity', ui.options._opacity);
	}
});

$.ui.plugin.add("draggable", "scroll", {
	start: function(event, ui) {
		var o = ui.options;
		var i = $(this).data("draggable");

		if(i.scrollParent[0] != document && i.scrollParent[0].tagName != 'HTML') i.overflowOffset = i.scrollParent.offset();

	},
	drag: function(event, ui) {

		var o = ui.options, scrolled = false;
		var i = $(this).data("draggable");

		if(i.scrollParent[0] != document && i.scrollParent[0].tagName != 'HTML') {

			if((i.overflowOffset.top + i.scrollParent[0].offsetHeight) - event.pageY < o.scrollSensitivity)
				i.scrollParent[0].scrollTop = scrolled = i.scrollParent[0].scrollTop + o.scrollSpeed;
			else if(event.pageY - i.overflowOffset.top < o.scrollSensitivity)
				i.scrollParent[0].scrollTop = scrolled = i.scrollParent[0].scrollTop - o.scrollSpeed;

			if((i.overflowOffset.left + i.scrollParent[0].offsetWidth) - event.pageX < o.scrollSensitivity)
				i.scrollParent[0].scrollLeft = scrolled = i.scrollParent[0].scrollLeft + o.scrollSpeed;
			else if(event.pageX - i.overflowOffset.left < o.scrollSensitivity)
				i.scrollParent[0].scrollLeft = scrolled = i.scrollParent[0].scrollLeft - o.scrollSpeed;

		} else {

			if(event.pageY - $(document).scrollTop() < o.scrollSensitivity)
				scrolled = $(document).scrollTop($(document).scrollTop() - o.scrollSpeed);
			else if($(window).height() - (event.pageY - $(document).scrollTop()) < o.scrollSensitivity)
				scrolled = $(document).scrollTop($(document).scrollTop() + o.scrollSpeed);

			if(event.pageX - $(document).scrollLeft() < o.scrollSensitivity)
				scrolled = $(document).scrollLeft($(document).scrollLeft() - o.scrollSpeed);
			else if($(window).width() - (event.pageX - $(document).scrollLeft()) < o.scrollSensitivity)
				scrolled = $(document).scrollLeft($(document).scrollLeft() + o.scrollSpeed);

		}

		if(scrolled !== false && $.ui.ddmanager && !o.dropBehaviour)
			$.ui.ddmanager.prepareOffsets(i, event);



		//This is a special case where we need to modify a offset calculated on start, since the following happened:
		// 1. The position of the helper is absolute, so it's position is calculated based on the next positioned parent
		// 2. The actual offset parent is a child of the scroll parent, and the scroll parent isn't the document, which means that
		//    the scroll is included in the initial calculation of the offset of the parent, and never recalculated upon drag
		if(scrolled !== false && i.cssPosition == 'absolute' && i.scrollParent[0] != document && $.ui.contains(i.scrollParent[0], i.offsetParent[0])) {
			i.offset.parent = i._getParentOffset();
		}

	}
});

$.ui.plugin.add("draggable", "snap", {
	start: function(event, ui) {

		var inst = $(this).data("draggable");
		inst.snapElements = [];

		$(ui.options.snap.constructor != String ? ( ui.options.snap.items || ':data(draggable)' ) : ui.options.snap).each(function() {
			var $t = $(this); var $o = $t.offset();
			if(this != inst.element[0]) inst.snapElements.push({
				item: this,
				width: $t.outerWidth(), height: $t.outerHeight(),
				top: $o.top, left: $o.left
			});
		});

	},
	drag: function(event, ui) {

		var inst = $(this).data("draggable");
		var d = ui.options.snapTolerance;

		var x1 = ui.absolutePosition.left, x2 = x1 + inst.helperProportions.width,
			y1 = ui.absolutePosition.top, y2 = y1 + inst.helperProportions.height;

		for (var i = inst.snapElements.length - 1; i >= 0; i--){

			var l = inst.snapElements[i].left, r = l + inst.snapElements[i].width,
				t = inst.snapElements[i].top, b = t + inst.snapElements[i].height;

			//Yes, I know, this is insane ;)
			if(!((l-d < x1 && x1 < r+d && t-d < y1 && y1 < b+d) || (l-d < x1 && x1 < r+d && t-d < y2 && y2 < b+d) || (l-d < x2 && x2 < r+d && t-d < y1 && y1 < b+d) || (l-d < x2 && x2 < r+d && t-d < y2 && y2 < b+d))) {
				if(inst.snapElements[i].snapping) (inst.options.snap.release && inst.options.snap.release.call(inst.element, event, $.extend(inst._uiHash(), { snapItem: inst.snapElements[i].item })));
				inst.snapElements[i].snapping = false;
				continue;
			}

			if(ui.options.snapMode != 'inner') {
				var ts = Math.abs(t - y2) <= d;
				var bs = Math.abs(b - y1) <= d;
				var ls = Math.abs(l - x2) <= d;
				var rs = Math.abs(r - x1) <= d;
				if(ts) ui.position.top = inst._convertPositionTo("relative", { top: t - inst.helperProportions.height, left: 0 }).top;
				if(bs) ui.position.top = inst._convertPositionTo("relative", { top: b, left: 0 }).top;
				if(ls) ui.position.left = inst._convertPositionTo("relative", { top: 0, left: l - inst.helperProportions.width }).left;
				if(rs) ui.position.left = inst._convertPositionTo("relative", { top: 0, left: r }).left;
			}

			var first = (ts || bs || ls || rs);

			if(ui.options.snapMode != 'outer') {
				var ts = Math.abs(t - y1) <= d;
				var bs = Math.abs(b - y2) <= d;
				var ls = Math.abs(l - x1) <= d;
				var rs = Math.abs(r - x2) <= d;
				if(ts) ui.position.top = inst._convertPositionTo("relative", { top: t, left: 0 }).top;
				if(bs) ui.position.top = inst._convertPositionTo("relative", { top: b - inst.helperProportions.height, left: 0 }).top;
				if(ls) ui.position.left = inst._convertPositionTo("relative", { top: 0, left: l }).left;
				if(rs) ui.position.left = inst._convertPositionTo("relative", { top: 0, left: r - inst.helperProportions.width }).left;
			}

			if(!inst.snapElements[i].snapping && (ts || bs || ls || rs || first))
				(inst.options.snap.snap && inst.options.snap.snap.call(inst.element, event, $.extend(inst._uiHash(), { snapItem: inst.snapElements[i].item })));
			inst.snapElements[i].snapping = (ts || bs || ls || rs || first);

		};

	}
});

$.ui.plugin.add("draggable", "stack", {
	start: function(event, ui) {
		var group = $.makeArray($(ui.options.stack.group)).sort(function(a,b) {
			return (parseInt($(a).css("zIndex"),10) || ui.options.stack.min) - (parseInt($(b).css("zIndex"),10) || ui.options.stack.min);
		});

		$(group).each(function(i) {
			this.style.zIndex = ui.options.stack.min + i;
		});

		this[0].style.zIndex = ui.options.stack.min + group.length;
	}
});

$.ui.plugin.add("draggable", "zIndex", {
	start: function(event, ui) {
		var t = $(ui.helper);
		if(t.css("zIndex")) ui.options._zIndex = t.css("zIndex");
		t.css('zIndex', ui.options.zIndex);
	},
	stop: function(event, ui) {
		if(ui.options._zIndex) $(ui.helper).css('zIndex', ui.options._zIndex);
	}
});

})(jQuery);