470 lines
17 KiB
JavaScript
470 lines
17 KiB
JavaScript
var DragDropTouch;
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(function(DragDropTouch_1) {
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'use strict';
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/**
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* Object used to hold the data that is being dragged during drag and drop operations.
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*
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* It may hold one or more data items of different types. For more information about
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* drag and drop operations and data transfer objects, see
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* <a href="https://developer.mozilla.org/en-US/docs/Web/API/DataTransfer">HTML Drag and Drop API</a>.
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*
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* This object is created automatically by the @see:DragDropTouch singleton and is
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* accessible through the @see:dataTransfer property of all drag events.
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*/
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var DataTransfer = (function() {
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function DataTransfer() {
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this._dropEffect = 'move';
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this._effectAllowed = 'all';
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this._data = {};
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}
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Object.defineProperty(DataTransfer.prototype, "dropEffect", {
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/**
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* Gets or sets the type of drag-and-drop operation currently selected.
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* The value must be 'none', 'copy', 'link', or 'move'.
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*/
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get: function() {
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return this._dropEffect;
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},
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set: function(value) {
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this._dropEffect = value;
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},
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enumerable: true,
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configurable: true
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});
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Object.defineProperty(DataTransfer.prototype, "effectAllowed", {
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/**
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* Gets or sets the types of operations that are possible.
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* Must be one of 'none', 'copy', 'copyLink', 'copyMove', 'link',
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* 'linkMove', 'move', 'all' or 'uninitialized'.
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*/
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get: function() {
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return this._effectAllowed;
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},
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set: function(value) {
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this._effectAllowed = value;
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},
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enumerable: true,
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configurable: true
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});
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Object.defineProperty(DataTransfer.prototype, "types", {
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/**
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* Gets an array of strings giving the formats that were set in the @see:dragstart event.
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*/
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get: function() {
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return Object.keys(this._data);
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},
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enumerable: true,
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configurable: true
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});
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/**
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* Removes the data associated with a given type.
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*
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* The type argument is optional. If the type is empty or not specified, the data
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* associated with all types is removed. If data for the specified type does not exist,
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* or the data transfer contains no data, this method will have no effect.
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*
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* @param type Type of data to remove.
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*/
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DataTransfer.prototype.clearData = function(type) {
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if (type != null) {
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delete this._data[type];
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} else {
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this._data = null;
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}
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};
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/**
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* Retrieves the data for a given type, or an empty string if data for that type does
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* not exist or the data transfer contains no data.
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*
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* @param type Type of data to retrieve.
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*/
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DataTransfer.prototype.getData = function(type) {
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return this._data[type] || '';
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};
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/**
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* Set the data for a given type.
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*
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* For a list of recommended drag types, please see
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* https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Recommended_Drag_Types.
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*
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* @param type Type of data to add.
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* @param value Data to add.
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*/
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DataTransfer.prototype.setData = function(type, value) {
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this._data[type] = value;
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};
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/**
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* Set the image to be used for dragging if a custom one is desired.
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*
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* @param img An image element to use as the drag feedback image.
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* @param offsetX The horizontal offset within the image.
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* @param offsetY The vertical offset within the image.
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*/
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DataTransfer.prototype.setDragImage = function(img, offsetX, offsetY) {
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var ddt = DragDropTouch._instance;
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ddt._imgCustom = img;
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ddt._imgOffset = {
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x: offsetX,
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y: offsetY
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};
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};
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return DataTransfer;
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}());
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DragDropTouch_1.DataTransfer = DataTransfer;
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/**
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* Defines a class that adds support for touch-based HTML5 drag/drop operations.
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*
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* The @see:DragDropTouch class listens to touch events and raises the
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* appropriate HTML5 drag/drop events as if the events had been caused
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* by mouse actions.
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*
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* The purpose of this class is to enable using existing, standard HTML5
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* drag/drop code on mobile devices running IOS or Android.
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*
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* To use, include the DragDropTouch.js file on the page. The class will
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* automatically start monitoring touch events and will raise the HTML5
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* drag drop events (dragstart, dragenter, dragleave, drop, dragend) which
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* should be handled by the application.
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*
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* For details and examples on HTML drag and drop, see
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* https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Drag_operations.
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*/
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var DragDropTouch = (function() {
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/**
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* Initializes the single instance of the @see:DragDropTouch class.
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*/
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function DragDropTouch() {
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this._lastClick = 0;
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// enforce singleton pattern
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if (DragDropTouch._instance) {
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throw 'DragDropTouch instance already created.';
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}
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// detect passive event support
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// https://github.com/Modernizr/Modernizr/issues/1894
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var supportsPassive = false;
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document.addEventListener('test', function() {}, {
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get passive() {
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supportsPassive = true;
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return true;
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}
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});
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// listen to touch events
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if (navigator.maxTouchPoints) {
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var d = document,
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ts = this._touchstart.bind(this),
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tm = this._touchmove.bind(this),
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te = this._touchend.bind(this),
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opt = supportsPassive ? {
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passive: false,
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capture: false
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} : false;
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d.addEventListener('touchstart', ts, opt);
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d.addEventListener('touchmove', tm, opt);
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d.addEventListener('touchend', te);
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d.addEventListener('touchcancel', te);
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}
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}
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/**
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* Gets a reference to the @see:DragDropTouch singleton.
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*/
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DragDropTouch.getInstance = function() {
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return DragDropTouch._instance;
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};
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// ** event handlers
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DragDropTouch.prototype._touchstart = function(e) {
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var _this = this;
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if (this._shouldHandle(e)) {
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// raise double-click and prevent zooming
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if (Date.now() - this._lastClick < DragDropTouch._DBLCLICK) {
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if (this._dispatchEvent(e, 'dblclick', e.target)) {
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e.preventDefault();
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this._reset();
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return;
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}
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}
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// clear all variables
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this._reset();
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// get nearest draggable element
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var src = this._closestDraggable(e.target);
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if (src) {
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// give caller a chance to handle the hover/move events
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if (!this._dispatchEvent(e, 'mousemove', e.target) &&
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!this._dispatchEvent(e, 'mousedown', e.target)) {
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// get ready to start dragging
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this._dragSource = src;
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this._ptDown = this._getPoint(e);
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this._lastTouch = e;
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e.preventDefault();
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// show context menu if the user hasn't started dragging after a while
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setTimeout(function() {
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if (_this._dragSource == src && _this._img == null) {
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if (_this._dispatchEvent(e, 'contextmenu', src)) {
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_this._reset();
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}
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}
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}, DragDropTouch._CTXMENU);
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if (DragDropTouch._ISPRESSHOLDMODE) {
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this._pressHoldInterval = setTimeout(function() {
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_this._isDragEnabled = true;
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_this._touchmove(e);
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}, DragDropTouch._PRESSHOLDAWAIT);
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}
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}
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}
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}
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};
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DragDropTouch.prototype._touchmove = function(e) {
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if (this._shouldCancelPressHoldMove(e)) {
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this._reset();
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return;
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}
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if (this._shouldHandleMove(e) || this._shouldHandlePressHoldMove(e)) {
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// see if target wants to handle move
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var target = this._getTarget(e);
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if (this._dispatchEvent(e, 'mousemove', target)) {
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this._lastTouch = e;
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e.preventDefault();
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return;
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}
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// start dragging
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if (this._dragSource && !this._img && this._shouldStartDragging(e)) {
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this._dispatchEvent(e, 'dragstart', this._dragSource);
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this._createImage(e);
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this._dispatchEvent(e, 'dragenter', target);
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}
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// continue dragging
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if (this._img) {
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this._lastTouch = e;
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e.preventDefault(); // prevent scrolling
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if (target != this._lastTarget) {
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this._dispatchEvent(this._lastTouch, 'dragleave', this._lastTarget);
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this._dispatchEvent(e, 'dragenter', target);
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this._lastTarget = target;
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}
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this._moveImage(e);
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this._isDropZone = this._dispatchEvent(e, 'dragover', target);
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}
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}
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};
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DragDropTouch.prototype._touchend = function(e) {
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if (this._shouldHandle(e)) {
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// see if target wants to handle up
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if (this._dispatchEvent(this._lastTouch, 'mouseup', e.target)) {
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e.preventDefault();
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return;
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}
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// user clicked the element but didn't drag, so clear the source and simulate a click
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if (!this._img) {
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this._dragSource = null;
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this._dispatchEvent(this._lastTouch, 'click', e.target);
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this._lastClick = Date.now();
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}
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// finish dragging
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this._destroyImage();
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if (this._dragSource) {
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if (e.type.indexOf('cancel') < 0 && this._isDropZone) {
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this._dispatchEvent(this._lastTouch, 'drop', this._lastTarget);
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}
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this._dispatchEvent(this._lastTouch, 'dragend', this._dragSource);
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this._reset();
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}
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}
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};
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// ** utilities
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// ignore events that have been handled or that involve more than one touch
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DragDropTouch.prototype._shouldHandle = function(e) {
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return e &&
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!e.defaultPrevented &&
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e.touches && e.touches.length < 2;
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};
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// use regular condition outside of press & hold mode
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DragDropTouch.prototype._shouldHandleMove = function(e) {
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return !DragDropTouch._ISPRESSHOLDMODE && this._shouldHandle(e);
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};
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// allow to handle moves that involve many touches for press & hold
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DragDropTouch.prototype._shouldHandlePressHoldMove = function(e) {
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return DragDropTouch._ISPRESSHOLDMODE &&
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this._isDragEnabled && e && e.touches && e.touches.length;
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};
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// reset data if user drags without pressing & holding
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DragDropTouch.prototype._shouldCancelPressHoldMove = function(e) {
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return DragDropTouch._ISPRESSHOLDMODE && !this._isDragEnabled &&
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this._getDelta(e) > DragDropTouch._PRESSHOLDMARGIN;
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};
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// start dragging when specified delta is detected
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DragDropTouch.prototype._shouldStartDragging = function(e) {
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var delta = this._getDelta(e);
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return delta > DragDropTouch._THRESHOLD ||
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(DragDropTouch._ISPRESSHOLDMODE && delta >= DragDropTouch._PRESSHOLDTHRESHOLD);
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}
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// clear all members
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DragDropTouch.prototype._reset = function() {
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this._destroyImage();
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this._dragSource = null;
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this._lastTouch = null;
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this._lastTarget = null;
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this._ptDown = null;
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this._isDragEnabled = false;
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this._isDropZone = false;
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this._dataTransfer = new DataTransfer();
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clearInterval(this._pressHoldInterval);
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};
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// get point for a touch event
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DragDropTouch.prototype._getPoint = function(e, page) {
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if (e && e.touches) {
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e = e.touches[0];
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}
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return {
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x: page ? e.pageX : e.clientX,
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y: page ? e.pageY : e.clientY
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};
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};
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// get distance between the current touch event and the first one
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DragDropTouch.prototype._getDelta = function(e) {
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if (DragDropTouch._ISPRESSHOLDMODE && !this._ptDown) {
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return 0;
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}
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var p = this._getPoint(e);
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return Math.abs(p.x - this._ptDown.x) + Math.abs(p.y - this._ptDown.y);
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};
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// get the element at a given touch event
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DragDropTouch.prototype._getTarget = function(e) {
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var pt = this._getPoint(e),
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el = document.elementFromPoint(pt.x, pt.y);
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while (el && getComputedStyle(el).pointerEvents == 'none') {
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el = el.parentElement;
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}
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return el;
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};
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// create drag image from source element
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DragDropTouch.prototype._createImage = function(e) {
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// just in case...
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if (this._img) {
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this._destroyImage();
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}
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// create drag image from custom element or drag source
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var src = this._imgCustom || this._dragSource;
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this._img = src.cloneNode(true);
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this._copyStyle(src, this._img);
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this._img.style.top = this._img.style.left = '-9999px';
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// if creating from drag source, apply offset and opacity
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if (!this._imgCustom) {
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var rc = src.getBoundingClientRect(),
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pt = this._getPoint(e);
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this._imgOffset = {
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x: pt.x - rc.left,
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y: pt.y - rc.top
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};
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this._img.style.opacity = DragDropTouch._OPACITY.toString();
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}
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// add image to document
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this._moveImage(e);
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document.body.appendChild(this._img);
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};
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// dispose of drag image element
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DragDropTouch.prototype._destroyImage = function() {
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if (this._img && this._img.parentElement) {
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this._img.parentElement.removeChild(this._img);
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}
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this._img = null;
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this._imgCustom = null;
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};
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// move the drag image element
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DragDropTouch.prototype._moveImage = function(e) {
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var _this = this;
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requestAnimationFrame(function() {
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if (_this._img) {
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var pt = _this._getPoint(e, true),
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s = _this._img.style;
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s.position = 'absolute';
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s.pointerEvents = 'none';
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s.zIndex = '999999';
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s.left = Math.round(pt.x - _this._imgOffset.x) + 'px';
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s.top = Math.round(pt.y - _this._imgOffset.y) + 'px';
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}
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});
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};
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// copy properties from an object to another
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DragDropTouch.prototype._copyProps = function(dst, src, props) {
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for (var i = 0; i < props.length; i++) {
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var p = props[i];
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dst[p] = src[p];
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}
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};
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DragDropTouch.prototype._copyStyle = function(src, dst) {
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// remove potentially troublesome attributes
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DragDropTouch._rmvAtts.forEach(function(att) {
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dst.removeAttribute(att);
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});
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// copy canvas content
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if (src instanceof HTMLCanvasElement) {
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var cSrc = src,
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cDst = dst;
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cDst.width = cSrc.width;
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cDst.height = cSrc.height;
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cDst.getContext('2d').drawImage(cSrc, 0, 0);
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}
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// copy style (without transitions)
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var cs = getComputedStyle(src);
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for (var i = 0; i < cs.length; i++) {
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var key = cs[i];
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if (key.indexOf('transition') < 0) {
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dst.style[key] = cs[key];
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}
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}
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dst.style.pointerEvents = 'none';
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// and repeat for all children
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for (var i = 0; i < src.children.length; i++) {
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this._copyStyle(src.children[i], dst.children[i]);
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}
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};
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DragDropTouch.prototype._dispatchEvent = function(e, type, target) {
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if (e && target) {
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var evt = document.createEvent('Event'),
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t = e.touches ? e.touches[0] : e;
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evt.initEvent(type, true, true);
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evt.button = 0;
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evt.which = evt.buttons = 1;
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this._copyProps(evt, e, DragDropTouch._kbdProps);
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this._copyProps(evt, t, DragDropTouch._ptProps);
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evt.dataTransfer = this._dataTransfer;
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target.dispatchEvent(evt);
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return evt.defaultPrevented;
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}
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return false;
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};
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// gets an element's closest draggable ancestor
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DragDropTouch.prototype._closestDraggable = function(e) {
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for (; e; e = e.parentElement) {
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if (e.hasAttribute('draggable') && e.draggable) {
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return e;
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}
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}
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return null;
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};
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return DragDropTouch;
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}());
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/*private*/
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DragDropTouch._instance = new DragDropTouch(); // singleton
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// constants
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DragDropTouch._THRESHOLD = 5; // pixels to move before drag starts
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DragDropTouch._OPACITY = 0.5; // drag image opacity
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DragDropTouch._DBLCLICK = 500; // max ms between clicks in a double click
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DragDropTouch._CTXMENU = 900; // ms to hold before raising 'contextmenu' event
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DragDropTouch._ISPRESSHOLDMODE = false; // decides of press & hold mode presence
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DragDropTouch._PRESSHOLDAWAIT = 400; // ms to wait before press & hold is detected
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DragDropTouch._PRESSHOLDMARGIN = 25; // pixels that finger might shiver while pressing
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DragDropTouch._PRESSHOLDTHRESHOLD = 0; // pixels to move before drag starts
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// copy styles/attributes from drag source to drag image element
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DragDropTouch._rmvAtts = 'id,class,style,draggable'.split(',');
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// synthesize and dispatch an event
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// returns true if the event has been handled (e.preventDefault == true)
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DragDropTouch._kbdProps = 'altKey,ctrlKey,metaKey,shiftKey'.split(',');
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DragDropTouch._ptProps = 'pageX,pageY,clientX,clientY,screenX,screenY,offsetX,offsetY'.split(',');
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DragDropTouch_1.DragDropTouch = DragDropTouch;
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})(DragDropTouch || (DragDropTouch = {}));
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