source: Dev/branches/jQueryUI/client/js/jquery/ui/jquery.ui.droppable.js @ 249

/*
 * jQuery UI Droppable 1.8.17
 *
 * Copyright 2011, AUTHORS.txt (http://jqueryui.com/about)
 * Dual licensed under the MIT or GPL Version 2 licenses.
 * http://jquery.org/license
 *
 * http://docs.jquery.com/UI/Droppables
 *
 * Depends:
 *      jquery.ui.core.js
 *      jquery.ui.widget.js
 *      jquery.ui.mouse.js
 *      jquery.ui.draggable.js
 */
(function( $, undefined ) {

$.widget("ui.droppable", {
        widgetEventPrefix: "drop",
        options: {
                accept: '*',
                activeClass: false,
                addClasses: true,
                greedy: false,
                hoverClass: false,
                scope: 'default',
                tolerance: 'intersect'
        },
        _create: function() {

                var o = this.options, accept = o.accept;
                this.isover = 0; this.isout = 1;

                this.accept = $.isFunction(accept) ? accept : function(d) {
                        return d.is(accept);
                };

                //Store the droppable's proportions
                this.proportions = { width: this.element[0].offsetWidth, height: this.element[0].offsetHeight };

                // Add the reference and positions to the manager
                $.ui.ddmanager.droppables[o.scope] = $.ui.ddmanager.droppables[o.scope] || [];
                $.ui.ddmanager.droppables[o.scope].push(this);

                (o.addClasses && this.element.addClass("ui-droppable"));

        },

        destroy: function() {
                var drop = $.ui.ddmanager.droppables[this.options.scope];
                for ( var i = 0; i < drop.length; i++ )
                        if ( drop[i] == this )
                                drop.splice(i, 1);

                this.element
                        .removeClass("ui-droppable ui-droppable-disabled")
                        .removeData("droppable")
                        .unbind(".droppable");

                return this;
        },

        _setOption: function(key, value) {

                if(key == 'accept') {
                        this.accept = $.isFunction(value) ? value : function(d) {
                                return d.is(value);
                        };
                }
                $.Widget.prototype._setOption.apply(this, arguments);
        },

        _activate: function(event) {
                var draggable = $.ui.ddmanager.current;
                if(this.options.activeClass) this.element.addClass(this.options.activeClass);
                (draggable && this._trigger('activate', event, this.ui(draggable)));
        },

        _deactivate: function(event) {
                var draggable = $.ui.ddmanager.current;
                if(this.options.activeClass) this.element.removeClass(this.options.activeClass);
                (draggable && this._trigger('deactivate', event, this.ui(draggable)));
        },

        _over: function(event) {

                var draggable = $.ui.ddmanager.current;
                if (!draggable || (draggable.currentItem || draggable.element)[0] == this.element[0]) return; // Bail if draggable and droppable are same element

                if (this.accept.call(this.element[0],(draggable.currentItem || draggable.element))) {
                        if(this.options.hoverClass) this.element.addClass(this.options.hoverClass);
                        this._trigger('over', event, this.ui(draggable));
                }

        },

        _out: function(event) {

                var draggable = $.ui.ddmanager.current;
                if (!draggable || (draggable.currentItem || draggable.element)[0] == this.element[0]) return; // Bail if draggable and droppable are same element

                if (this.accept.call(this.element[0],(draggable.currentItem || draggable.element))) {
                        if(this.options.hoverClass) this.element.removeClass(this.options.hoverClass);
                        this._trigger('out', event, this.ui(draggable));
                }

        },

        _drop: function(event,custom) {

                var draggable = custom || $.ui.ddmanager.current;
                if (!draggable || (draggable.currentItem || draggable.element)[0] == this.element[0]) return false; // Bail if draggable and droppable are same element

                var childrenIntersection = false;
                this.element.find(":data(droppable)").not(".ui-draggable-dragging").each(function() {
                        var inst = $.data(this, 'droppable');
                        if(
                                inst.options.greedy
                                && !inst.options.disabled
                                && inst.options.scope == draggable.options.scope
                                && inst.accept.call(inst.element[0], (draggable.currentItem || draggable.element))
                                && $.ui.intersect(draggable, $.extend(inst, { offset: inst.element.offset() }), inst.options.tolerance)
                        ) { childrenIntersection = true; return false; }
                });
                if(childrenIntersection) return false;

                if(this.accept.call(this.element[0],(draggable.currentItem || draggable.element))) {
                        if(this.options.activeClass) this.element.removeClass(this.options.activeClass);
                        if(this.options.hoverClass) this.element.removeClass(this.options.hoverClass);
                        this._trigger('drop', event, this.ui(draggable));
                        return this.element;
                }

                return false;

        },

        ui: function(c) {
                return {
                        draggable: (c.currentItem || c.element),
                        helper: c.helper,
                        position: c.position,
                        offset: c.positionAbs
                };
        }

});

$.extend($.ui.droppable, {
        version: "1.8.17"
});

$.ui.intersect = function(draggable, droppable, toleranceMode) {

        if (!droppable.offset) return false;

        var x1 = (draggable.positionAbs || draggable.position.absolute).left, x2 = x1 + draggable.helperProportions.width,
                y1 = (draggable.positionAbs || draggable.position.absolute).top, y2 = y1 + draggable.helperProportions.height;
        var l = droppable.offset.left, r = l + droppable.proportions.width,
                t = droppable.offset.top, b = t + droppable.proportions.height;

        switch (toleranceMode) {
                case 'fit':
                        return (l <= x1 && x2 <= r
                                && t <= y1 && y2 <= b);
                        break;
                case 'intersect':
                        return (l < x1 + (draggable.helperProportions.width / 2) // Right Half
                                && x2 - (draggable.helperProportions.width / 2) < r // Left Half
                                && t < y1 + (draggable.helperProportions.height / 2) // Bottom Half
                                && y2 - (draggable.helperProportions.height / 2) < b ); // Top Half
                        break;
                case 'pointer':
                        var draggableLeft = ((draggable.positionAbs || draggable.position.absolute).left + (draggable.clickOffset || draggable.offset.click).left),
                                draggableTop = ((draggable.positionAbs || draggable.position.absolute).top + (draggable.clickOffset || draggable.offset.click).top),
                                isOver = $.ui.isOver(draggableTop, draggableLeft, t, l, droppable.proportions.height, droppable.proportions.width);
                        return isOver;
                        break;
                case 'touch':
                        return (
                                        (y1 >= t && y1 <= b) || // Top edge touching
                                        (y2 >= t && y2 <= b) || // Bottom edge touching
                                        (y1 < t && y2 > b)              // Surrounded vertically
                                ) && (
                                        (x1 >= l && x1 <= r) || // Left edge touching
                                        (x2 >= l && x2 <= r) || // Right edge touching
                                        (x1 < l && x2 > r)              // Surrounded horizontally
                                );
                        break;
                default:
                        return false;
                        break;
                }

};

/*
        This manager tracks offsets of draggables and droppables
*/
$.ui.ddmanager = {
        current: null,
        droppables: { 'default': [] },
        prepareOffsets: function(t, event) {

                var m = $.ui.ddmanager.droppables[t.options.scope] || [];
                var type = event ? event.type : null; // workaround for #2317
                var list = (t.currentItem || t.element).find(":data(droppable)").andSelf();

                droppablesLoop: for (var i = 0; i < m.length; i++) {

                        if(m[i].options.disabled || (t && !m[i].accept.call(m[i].element[0],(t.currentItem || t.element)))) continue;   //No disabled and non-accepted
                        for (var j=0; j < list.length; j++) { if(list[j] == m[i].element[0]) { m[i].proportions.height = 0; continue droppablesLoop; } }; //Filter out elements in the current dragged item
                        m[i].visible = m[i].element.css("display") != "none"; if(!m[i].visible) continue;                                                                       //If the element is not visible, continue

                        if(type == "mousedown") m[i]._activate.call(m[i], event); //Activate the droppable if used directly from draggables

                        m[i].offset = m[i].element.offset();
                        m[i].proportions = { width: m[i].element[0].offsetWidth, height: m[i].element[0].offsetHeight };

                }

        },
        drop: function(draggable, event) {

                var dropped = false;
                $.each($.ui.ddmanager.droppables[draggable.options.scope] || [], function() {

                        if(!this.options) return;
                        if (!this.options.disabled && this.visible && $.ui.intersect(draggable, this, this.options.tolerance))
                                dropped = this._drop.call(this, event) || dropped;

                        if (!this.options.disabled && this.visible && this.accept.call(this.element[0],(draggable.currentItem || draggable.element))) {
                                this.isout = 1; this.isover = 0;
                                this._deactivate.call(this, event);
                        }

                });
                return dropped;

        },
        dragStart: function( draggable, event ) {
                //Listen for scrolling so that if the dragging causes scrolling the position of the droppables can be recalculated (see #5003)
                draggable.element.parents( ":not(body,html)" ).bind( "scroll.droppable", function() {
                        if( !draggable.options.refreshPositions ) $.ui.ddmanager.prepareOffsets( draggable, event );
                });
        },
        drag: function(draggable, event) {

                //If you have a highly dynamic page, you might try this option. It renders positions every time you move the mouse.
                if(draggable.options.refreshPositions) $.ui.ddmanager.prepareOffsets(draggable, event);

                //Run through all droppables and check their positions based on specific tolerance options
                $.each($.ui.ddmanager.droppables[draggable.options.scope] || [], function() {

                        if(this.options.disabled || this.greedyChild || !this.visible) return;
                        var intersects = $.ui.intersect(draggable, this, this.options.tolerance);

                        var c = !intersects && this.isover == 1 ? 'isout' : (intersects && this.isover == 0 ? 'isover' : null);
                        if(!c) return;

                        var parentInstance;
                        if (this.options.greedy) {
                                var parent = this.element.parents(':data(droppable):eq(0)');
                                if (parent.length) {
                                        parentInstance = $.data(parent[0], 'droppable');
                                        parentInstance.greedyChild = (c == 'isover' ? 1 : 0);
                                }
                        }

                        // we just moved into a greedy child
                        if (parentInstance && c == 'isover') {
                                parentInstance['isover'] = 0;
                                parentInstance['isout'] = 1;
                                parentInstance._out.call(parentInstance, event);
                        }

                        this[c] = 1; this[c == 'isout' ? 'isover' : 'isout'] = 0;
                        this[c == "isover" ? "_over" : "_out"].call(this, event);

                        // we just moved out of a greedy child
                        if (parentInstance && c == 'isout') {
                                parentInstance['isout'] = 0;
                                parentInstance['isover'] = 1;
                                parentInstance._over.call(parentInstance, event);
                        }
                });

        },
        dragStop: function( draggable, event ) {
                draggable.element.parents( ":not(body,html)" ).unbind( "scroll.droppable" );
                //Call prepareOffsets one final time since IE does not fire return scroll events when overflow was caused by drag (see #5003)
                if( !draggable.options.refreshPositions ) $.ui.ddmanager.prepareOffsets( draggable, event );
        }
};

})(jQuery);