source: Dev/trunk/src/client/dojox/mdnd/dropMode/DefaultDropMode.js

define([
        "dojo/_base/kernel",
        "dojo/_base/declare",
        "dojo/_base/array",
        "dojo/dom-geometry",
        "dojox/mdnd/AreaManager"
],function(dojo, declare, array, geom){
        var ddm = declare("dojox.mdnd.dropMode.DefaultDropMode", null, {
                // summary:
                //              Enabled a type of calcul for Dnd.
                //              Default class to find the nearest target.
        
                // _oldXPoint: Integer
                //              used to save a X position
                _oldXPoint: null,
        
                // _oldYPoint: Integer
                //              used to save a Y position
                _oldYPoint: null,
        
                // _oldBehaviour: String
                //              see `getDragPoint`
                _oldBehaviour: "up",
        
                addArea: function(/*Array*/areas, /*Object*/object){
                        // summary:
                        //              Add a DnD Area into an array sorting by the x position.
                        // areas:
                        //              array of areas
                        // object:
                        //              data type of a DndArea
                        // returns:
                        //              a sorted area
        
                        //console.log("dojox.mdnd.dropMode.DefaultDropMode ::: addArea");
                        var length =  areas.length;
                        var position = geom.position(object.node, true);
                        object.coords = {'x':position.x, 'y':position.y};
                        if (length == 0) {
                                areas.push(object);
                        }else{
                                var x =  object.coords.x;
                                for (var i = 0; i < length; i++) {
                                        if (x < areas[i].coords.x) {
                                                for (var j = length-1; j >= i; j--)
                                                        areas[j + 1] = areas[j];
                                                areas[i] = object;
                                                break;
                                        }
                                }
                                if (i == length)
                                        areas.push(object);
                        }
                        return areas;   // Array
                },
        
                updateAreas: function(/*Array*/areaList){
                        // summary:
                        //              Refresh intervals between areas to determinate the nearest area to drop an item.
                        //              Algorithm :
                        //              the marker should be the vertical line passing by the
                        //              central point between two contiguous areas.
                        //              Note:
                        //              If the page has only one targetArea, it's not necessary to calculate coords.
                        // areaList:
                        //              array of areas
        
                        //console.log("dojox.mdnd.dropMode.DefaultDropMode ::: initAreas");
                        var length = areaList.length;
                        if (length > 1){
                                var currentRight, nextLeft;
                                for (var i = 0; i < length; i++) {
                                        var area = areaList[i];
                                        var nextArea;
                                        area.coords.x1 = -1;
                                        area.coords.x2 = -1;
                                        if (i == 0) {
                                                nextArea = areaList[i+1];
                                                this._updateArea(area);
                                                this._updateArea(nextArea);
                                                currentRight = area.coords.x + area.node.offsetWidth;
                                                nextLeft =  nextArea.coords.x;
                                                area.coords.x2 = currentRight + (nextLeft-currentRight)/2;
                                        }
                                        else if (i == length-1) {
                                                area.coords.x1 = areaList[i-1].coords.x2;
                                        }else{
                                                nextArea = areaList[i+1];
                                                this._updateArea(nextArea);
                                                currentRight = area.coords.x + area.node.offsetWidth;
                                                nextLeft =  nextArea.coords.x;
                                                area.coords.x1 = areaList[i-1].coords.x2;
                                                area.coords.x2 = currentRight + (nextLeft-currentRight)/2;
                                        }
                                }
                        }
                },
        
                _updateArea : function(/*Object*/area){
                        // summary:
                        //              update the DnD area object (i.e. update coordinates of its DOM node)
                        // area:
                        //              the DnD area
                        // tags:
                        //              protected
        
                        //console.log("dojox.mdnd.dropMode.DefaultDropMode  ::: _updateArea");
                        var position = geom.position(area.node, true);
                        area.coords.x = position.x;
                        area.coords.y = position.y;
                },
        
                initItems: function(/*Object*/area){
                        // summary:
                        //              initialize the horizontal line in order to determinate the drop zone.
                        // area:
                        //              the DnD area
        
                        //console.log("dojox.mdnd.dropMode.DefaultDropMode ::: initItems");
                        array.forEach(area.items, function(obj){
                                //get the vertical middle of the item
                                var node = obj.item.node;
                                var position = geom.position(node, true);
                                var y = position.y + position.h/2;
                                obj.y = y;
                        });
                        area.initItems = true;
                },
        
                refreshItems: function(/*Object*/area, /*Integer*/indexItem, /*Object*/size, /*Boolean*/added){
                        // summary:
                        //              take into account the drop indicator DOM element in order to compute horizontal lines
                        // area:
                        //              a DnD area object
                        // indexItem:
                        //              index of a draggable item
                        // size:
                        //              dropIndicator size
                        // added:
                        //              boolean to know if a dropIndicator has been added or deleted
        
                        //console.log("dojox.mdnd.dropMode.DefaultDropMode ::: refreshItems");
                        if (indexItem == -1) {
                                return;
                        }else if(area && size && size.h){
                                var height = size.h;
                                if (area.margin){
                                        height += area.margin.t;
                                }
                                var length = area.items.length;
                                for (var i=indexItem; i<length; i++){
                                        var item = area.items[i];
                                        if (added) {
                                                item.y += height;
                                        }else{
                                                item.y -= height;
                                        }
                                }
                        }
                },
        
                getDragPoint: function(/*Object*/coords, /*Object*/size, /*Object*/mousePosition){
                        // summary:
                        //              return coordinates of the draggable item
                        // description:
                        //              return for:
                        //
                        //              - X point : the middle
                        //              - Y point : search if the user goes up or goes down with his mouse.
                        //              - Up : top of the draggable item
                        //              - Down : bottom of the draggable item
                        // coords:
                        //              an object encapsulating X and Y position
                        // size:
                        //              an object encapsulating width and height values
                        // mousePosition:
                        //              coordinates of mouse
                        // returns:
                        //              an object of coordinates
                        //              example : {'x':10,'y':10}
        
                        //console.log("dojox.mdnd.dropMode.DefaultDropMode ::: getDragPoint");
                        var y = coords.y;
                        if (this._oldYPoint){
                                if (y > this._oldYPoint) {
                                        this._oldBehaviour = "down";
                                        y += size.h;
                                }
                                else
                                        if (y <= this._oldYPoint) {
                                                this._oldBehaviour = "up";
                                        }
                        }
                        this._oldYPoint = y;
                        return {
                                'x': coords.x + (size.w / 2),
                                'y': y
                                };      // Object
                },
        
                getTargetArea: function(/*Array*/areaList, /*Object*/ coords, /*integer*/currentIndexArea ){
                        // summary:
                        //              get the nearest DnD area.
                        //              Coordinates are basically provided by the ``getDragPoint`` method.
                        // areaList:
                        //              a list of DnD areas objects
                        // coords:
                        //              coordinates [x,y] of the dragItem
                        // currentIndexArea:
                        //              an index representing the active DnD area
                        // returns:
                        //              the index of the DnD area
        
                        //console.log("dojox.mdnd.dropMode.DefaultDropMode ::: getTargetArea");
                        var index = 0;
                        var x = coords.x;
                        var end = areaList.length;
                        if (end > 1) {
                                var start = 0, direction = "right", compute = false;
                                if (currentIndexArea == -1 || arguments.length<3) {
                                        // first time : Need to search the nearest area in all areas.
                                        compute = true;
                                }
                                else {
                                        // check if it's always the same area
                                        if (this._checkInterval(areaList, currentIndexArea, x)){
                                                index = currentIndexArea;
                                        }else{
                                                if (this._oldXPoint < x){
                                                        start = currentIndexArea + 1;
                                                }else{
                                                        start = currentIndexArea - 1;
                                                        end = 0;
                                                        direction = "left";
                                                }
                                                compute = true;
                                        }
                                }
                                if (compute) {
                                        if (direction === "right") {
                                                for (var i = start; i < end; i++) {
                                                        if (this._checkInterval(areaList, i, x)) {
                                                                index = i;
                                                                break;
                                                        }
                                                }
                                        }else{
                                                for (var i = start; i >= end; i--) {
                                                        if (this._checkInterval(areaList, i, x)) {
                                                                index = i;
                                                                break;
                                                        }
                                                }
                                        }
                                }
                        }
                        this._oldXPoint = x;
                        return index;   // Integer
                },
        
                _checkInterval: function(/*Array*/areaList, /*Integer*/index, /*Coord*/x){
                        // summary:
                        //              check if the dragNode is in the interval.
                        //              The x coordinate is basically provided by the ``getDragPoint`` method.
                        // areaList:
                        //              a list of DnD areas objects
                        // index:
                        //              index of a DnD area (to get the interval)
                        // x:
                        //              coordinate x, of the dragNode
                        // returns:
                        //              true if the dragNode is in interval
                        // tags:
                        //              protected
        
                        var coords = areaList[index].coords;
                        if (coords.x1 == -1) {
                                if (x <= coords.x2) {
                                        return true;
                                }
                        }
                        else
                                if (coords.x2 == -1) {
                                        if (x > coords.x1) {
                                                return true;
                                        }
                                }
                                else {
                                        if (coords.x1 < x && x <= coords.x2) {
                                                return true;
                                        }
                                }
                        return false;   // Boolean
                },
        
                getDropIndex: function(/*Object*/ targetArea, /*Object*/ coords){
                        // summary:
                        //              Return the index where the drop has to be placed.
                        // targetArea:
                        //              a DnD area object
                        // coords:
                        //              coordinates [x,y] of the draggable item
                        // returns:
                        //              a number
                        //              or -1 if the area has no children or the drop index represents the last position in to the area
        
                        //console.log("dojox.mdnd.dropMode.DefaultDropMode ::: getDropIndex");
                        var length = targetArea.items.length;
                        var coordinates = targetArea.coords;
                        var y = coords.y;
                        if (length > 0) {
                                // course all children in the target area.
                                for (var i = 0; i < length; i++) {
                                        // compare y value with y value of children
                                        if (y < targetArea.items[i].y) {
                                                return i;       // Integer
                                        }
                                        else {
                                                if (i == length-1) {
                                                        return -1;
                                                }
                                        }
                                }
                        }
                        return -1;
                },
        
                destroy: function(){
                        //      can be overwritten.
                }
        });
        
        //------------
        //Singleton
        //------------
        dojox.mdnd.areaManager()._dropMode = new dojox.mdnd.dropMode.DefaultDropMode();
        return ddm;
});