src/editor/modules/documentCanvas/canvas/canvas.js

   1 define([
   2 'libs/jquery',
   3 'libs/underscore',
   4 'libs/backbone',
   5 'modules/documentCanvas/canvas/documentElement',
   6 'modules/documentCanvas/canvas/keyboard',
   7 'modules/documentCanvas/canvas/utils'
   8 ], function($, _, Backbone, documentElement, keyboard, utils) {
   9
  10 'use strict';
  11
  12 var Canvas = function(wlxml, publisher, ver) {
  13     this.eventBus = _.extend({}, Backbone.Events);
  14     if(ver === 2) {
  15         this.loadWlxmlDocument(wlxml);
  16     } else {
  17         this.loadWlxml(wlxml);
  18     }
  19     this.publisher = publisher ? publisher : function() {};
  20 };
  21
  22 $.extend(Canvas.prototype, {
  23
  24     loadWlxmlDocument: function(wlxmlDocument) {
  25         var canvasDOM = this.generateCanvasDOM(wlxmlDocument.root);
  26
  27         this.wrapper = $('<div>').addClass('canvas-wrapper').attr('contenteditable', true);
  28         this.wrapper.append(canvasDOM);
  29         this.d = this.wrapper.children(0);
  30         this.setupEventHandling();
  31     },
  32
  33     generateCanvasDOM: function(wlxmlNode) {
  34         // var element = this.createNodeElement2({
  35         //     tag: wlxmlNode.getTagName(),
  36         //     klass: wlxmlNode.getClass(), //currentTag.attr('class'),
  37         //     meta: wlxmlNode.getMetaAttributes(), //meta,
  38         //     others: wlxmlNode.getOtherAttributes(), // ~ //others,
  39         //     rawChildren: wlxmlNode.contents(),
  40         //     prepopulateOnEmpty: true
  41         // }); //->create2
  42
  43         var element = documentElement.DocumentNodeElement.create2(wlxmlNode, this);
  44
  45
  46         ['orig-before', 'orig-after', 'orig-begin', 'orig-end'].forEach(function(attr) {
  47             element.data(attr, '');
  48         });
  49         return element.dom();
  50     },
  51
  52     loadWlxml: function(wlxml) {
  53         var d = wlxml ? $($.trim(wlxml)) : null;
  54         if(d) {
  55             this.wrapper = $('<div>').addClass('canvas-wrapper').attr('contenteditable', true);
  56             this.wrapper.append(d);
  57             var canvas = this;
  58
  59             this.wrapper.find('*').replaceWith(function() {
  60                 var currentTag = $(this);
  61                 if(currentTag.attr('wlxml-tag'))
  62                     return;
  63
  64                 var meta = {}, others = {};
  65                 for(var i = 0; i < this.attributes.length; i++) {
  66                     var attr = this.attributes[i];
  67                     if(attr.name.substr(0, 5) === 'meta-')
  68                         meta[attr.name.substr(5)] = attr.value;
  69                     else if(attr.name !== 'class')
  70                         others[attr.name] = attr.value;
  71                 }
  72
  73                 var element = canvas.createNodeElement({
  74                     tag: currentTag.prop('tagName').toLowerCase(),
  75                     klass: currentTag.attr('class'),
  76                     meta: meta,
  77                     others: others,
  78                     rawChildren: currentTag.contents(),
  79                     prepopulateOnEmpty: true
  80                 });
  81
  82                 ['orig-before', 'orig-after', 'orig-begin', 'orig-end'].forEach(function(attr) {
  83                     element.data(attr, '');
  84                 });
  85                 return element.dom();
  86             });
  87
  88             var FIRST_CONTENT_INDEX = 0;
  89
  90             // @@ TODO - refactor!
  91             var getNode = function(element) {
  92                 return element.children('[document-element-content]');
  93             }
  94
  95             this.wrapper.find(':not(iframe)').addBack().contents()
  96                 .filter(function() {return this.nodeType === Node.TEXT_NODE})
  97                 .each(function() {
  98
  99                     // TODO: use DocumentElement API
 100
 101                     var el = $(this),
 102                         text = {original: el.text(), trimmed: $.trim(el.text())},
 103                         elParent = el.parent(),
 104                         hasSpanParent = elParent.attr('wlxml-tag') === 'span',
 105                         hasSpanBefore = el.prev().length > 0  && getNode($(el.prev()[0])).attr('wlxml-tag') === 'span',
 106                         hasSpanAfter = el.next().length > 0 && getNode($(el.next()[0])).attr('wlxml-tag') === 'span';
 107
 108                     if(el.parent().hasClass('canvas-widget') || elParent.attr('document-text-element') !== undefined)
 109                         return true; // continue
 110
 111                     var addInfo = function(toAdd, where) {
 112                         var parentContents = elParent.contents(),
 113                             idx = parentContents.index(el[0]),
 114                             prev = idx > FIRST_CONTENT_INDEX ? parentContents[idx-1] : null,
 115                             next = idx < parentContents.length - 1 ? parentContents[idx+1] : null,
 116                             target, key;
 117
 118                         if(where === 'above') {
 119                             target = prev ? $(prev) : elParent.parent();
 120                             key = prev ? 'orig-after' : 'orig-begin';
 121                         } else if(where === 'below') {
 122                             target = next ? $(next) : elParent.parent();
 123                             key = next ? 'orig-before' : 'orig-end';
 124                         } else { throw new Object;}
 125
 126                         target.data(key, toAdd);
 127                     }
 128
 129                     text.transformed = text.trimmed;
 130
 131                     if(hasSpanParent || hasSpanBefore || hasSpanAfter) {
 132                         var startSpace = /\s/g.test(text.original.substr(0,1)),
 133                             endSpace = /\s/g.test(text.original.substr(-1)) && text.original.length > 1;
 134                         text.transformed = (startSpace && (hasSpanParent || hasSpanBefore) ? ' ' : '')
 135                                     + text.trimmed
 136                                     + (endSpace && (hasSpanParent || hasSpanAfter) ? ' ' : '');
 137                     } else {
 138                         if(text.trimmed.length === 0 && text.original.length > 0 && elParent.contents().length === 1)
 139                             text.transformed = ' ';
 140                     }
 141
 142                     if(!text.transformed) {
 143                         addInfo(text.original, 'below');
 144                         el.remove();
 145                         return true; // continue
 146                     }
 147
 148                     if(text.transformed !== text.original) {
 149                         if(!text.trimmed) {
 150                             addInfo(text.original, 'below');
 151                         } else {
 152                             var startingMatch = text.original.match(/^\s+/g),
 153                                 endingMatch = text.original.match(/\s+$/g),
 154                                 startingWhiteSpace = startingMatch ? startingMatch[0] : null,
 155                                 endingWhiteSpace = endingMatch ? endingMatch[0] : null;
 156
 157                             if(endingWhiteSpace) {
 158                                 if(text.transformed[text.transformed.length - 1] === ' ' && endingWhiteSpace[0] === ' ')
 159                                     endingWhiteSpace = endingWhiteSpace.substr(1);
 160                                 addInfo(endingWhiteSpace, 'below');
 161                             }
 162
 163                             if(startingWhiteSpace) {
 164                                 if(text.transformed[0] === ' ' && startingWhiteSpace[startingWhiteSpace.length-1] === ' ')
 165                                     startingWhiteSpace = startingWhiteSpace.substr(0, startingWhiteSpace.length -1);
 166                                 addInfo(startingWhiteSpace, 'above');
 167                             }
 168                         }
 169                     }
 170
 171                     var element = documentElement.DocumentTextElement.create({text: text.transformed});
 172                     el.replaceWith(element.dom());
 173                 });
 174
 175             this.d = this.wrapper.children(0);
 176
 177             this.setupEventHandling();
 178
 179         } else {
 180             this.d = null;
 181         }
 182     },
 183
 184     setupEventHandling: function() {
 185         var canvas = this;
 186         this.wrapper.on('keyup keydown keypress', function(e) {
 187             keyboard.handleKey(e, this);
 188         }.bind(this));
 189
 190         this.wrapper.on('click', '[document-node-element], [document-text-element]', function(e) {
 191             e.stopPropagation();
 192             canvas.setCurrentElement(canvas.getDocumentElement(e.currentTarget), {caretTo: false});
 193         });
 194
 195         var observer = new MutationObserver(function(mutations) {
 196             mutations.forEach(function(mutation) {
 197                 if(documentElement.DocumentTextElement.isContentContainer(mutation.target)) {
 198                     observer.disconnect();
 199                     if(mutation.target.data === '')
 200                         mutation.target.data = utils.unicode.ZWS;
 201                     else if(mutation.oldValue === utils.unicode.ZWS) {
 202                         mutation.target.data = mutation.target.data.replace(utils.unicode.ZWS, '');
 203                         canvas._moveCaretToTextElement(canvas.getDocumentElement(mutation.target), 'end');
 204                     }
 205                     observer.observe(canvas.d[0], config);
 206                     canvas.publisher('contentChanged');
 207                 }
 208             });
 209         });
 210         var config = { attributes: false, childList: false, characterData: true, subtree: true, characterDataOldValue: true};
 211         observer.observe(this.d[0], config);
 212
 213
 214         this.wrapper.on('mouseover', '[document-node-element], [document-text-element]', function(e) {
 215             var el = canvas.getDocumentElement(e.currentTarget);
 216             if(!el)
 217                 return;
 218             e.stopPropagation();
 219             if(el instanceof documentElement.DocumentTextElement)
 220                 el = el.parent();
 221             el.toggleLabel(true);
 222         });
 223         this.wrapper.on('mouseout', '[document-node-element], [document-text-element]', function(e) {
 224             var el = canvas.getDocumentElement(e.currentTarget);
 225             if(!el)
 226                 return;
 227             e.stopPropagation();
 228             if(el instanceof documentElement.DocumentTextElement)
 229                 el = el.parent();
 230             el.toggleLabel(false);
 231         });
 232
 233         this.eventBus.on('elementToggled', function(toggle, element) {
 234             if(!toggle) {
 235                 canvas.setCurrentElement(element.getPreviousTextElement());
 236             }
 237         });
 238     },
 239
 240     view: function() {
 241         return this.wrapper;
 242     },
 243
 244     doc: function() {
 245         if(this.d === null)
 246             return null;
 247         return documentElement.DocumentNodeElement.fromHTMLElement(this.d.get(0), this); //{wlxmlTag: this.d.prop('tagName')};
 248     },
 249
 250     createNodeElement: function(params) {
 251         return documentElement.DocumentNodeElement.create(params, this);
 252     },
 253
 254     wrapText: function(params) {
 255         params = _.extend({textNodeIdx: 0}, params);
 256         if(typeof params.textNodeIdx === 'number')
 257             params.textNodeIdx = [params.textNodeIdx];
 258
 259         var childrenInside = params.inside.children(),
 260             idx1 = Math.min.apply(Math, params.textNodeIdx),
 261             idx2 = Math.max.apply(Math, params.textNodeIdx),
 262             textNode1 = childrenInside[idx1],
 263             textNode2 = childrenInside[idx2],
 264             sameNode = textNode1.sameNode(textNode2),
 265             prefixOutside = textNode1.getText().substr(0, params.offsetStart),
 266             prefixInside = textNode1.getText().substr(params.offsetStart),
 267             suffixInside = textNode2.getText().substr(0, params.offsetEnd),
 268             suffixOutside = textNode2.getText().substr(params.offsetEnd)
 269         ;
 270
 271         var wrapperElement = this.createNodeElement({tag: params._with.tag, klass: params._with.klass});
 272         textNode1.after(wrapperElement);
 273         textNode1.detach();
 274
 275         if(prefixOutside.length > 0)
 276             wrapperElement.before({text:prefixOutside});
 277         if(sameNode) {
 278             var core = textNode1.getText().substr(params.offsetStart, params.offsetEnd - params.offsetStart);
 279             wrapperElement.append({text: core});
 280         } else {
 281             textNode2.detach();
 282             if(prefixInside.length > 0)
 283                 wrapperElement.append({text: prefixInside});
 284             for(var i = idx1 + 1; i < idx2; i++) {
 285                 wrapperElement.append(childrenInside[i]);
 286             }
 287             if(suffixInside.length > 0)
 288                 wrapperElement.append({text: suffixInside});
 289         }
 290         if(suffixOutside.length > 0)
 291             wrapperElement.after({text: suffixOutside});
 292         return wrapperElement;
 293     },
 294
 295     wrapElements: function(params) {
 296         if(!(params.element1.parent().sameNode(params.element2.parent())))
 297             return;
 298
 299         var parent = params.element1.parent(),
 300             parentChildren = parent.children(),
 301             wrapper = this.createNodeElement({
 302                 tag: params._with.tag,
 303                 klass: params._with.klass}),
 304             idx1 = parent.childIndex(params.element1),
 305             idx2 = parent.childIndex(params.element2);
 306
 307         if(idx1 > idx2) {
 308             var tmp = idx1;
 309             idx1 = idx2;
 310             idx2 = tmp;
 311         }
 312
 313         var insertingMethod, insertingTarget;
 314         if(idx1 === 0) {
 315             insertingMethod = 'prepend';
 316             insertingTarget = parent;
 317         } else {
 318             insertingMethod = 'after';
 319             insertingTarget = parentChildren[idx1-1];
 320         }
 321
 322         for(var i = idx1; i <= idx2; i++) {
 323             wrapper.append(parentChildren[i].detach());
 324         }
 325
 326         insertingTarget[insertingMethod](wrapper);
 327         return wrapper;
 328     },
 329
 330     getSiblingParents: function(params) {
 331         var parents1 = [params.element1].concat(params.element1.parents()).reverse(),
 332             parents2 = [params.element2].concat(params.element2.parents()).reverse(),
 333             noSiblingParents = null;
 334
 335         if(parents1.length === 0 || parents2.length === 0 || !(parents1[0].sameNode(parents2[0])))
 336             return noSiblingParents;
 337
 338         var i;
 339         for(i = 0; i < Math.min(parents1.length, parents2.length); i++) {
 340             if(parents1[i].sameNode(parents2[i]))
 341                 continue;
 342             break;
 343         }
 344         return {element1: parents1[i], element2: parents2[i]};
 345     },
 346
 347     getDocumentElement: function(from) {
 348         if(from instanceof HTMLElement || from instanceof Text) {
 349            return documentElement.DocumentElement.fromHTMLElement(from, this);
 350         }
 351     },
 352     getCursor: function() {
 353         return new Cursor(this);
 354     },
 355
 356     list: {},
 357
 358
 359     getCurrentNodeElement: function() {
 360         return this.getDocumentElement(this.wrapper.find('.current-node-element').parent()[0]);
 361     },
 362
 363     getCurrentTextElement: function() {
 364         return this.getDocumentElement(this.wrapper.find('.current-text-element')[0]);
 365     },
 366
 367
 368
 369     setCurrentElement: function(element, params) {
 370         params = _.extend({caretTo: 'end'}, params);
 371         var findFirstDirectTextChild = function(e, nodeToLand) {
 372             var byBrowser = this.getCursor().getPosition().element;
 373             if(byBrowser && byBrowser.parent().sameNode(nodeToLand))
 374                 return byBrowser;
 375             var children = e.children();
 376             for(var i = 0; i < children.length; i++) {
 377                 if(children[i] instanceof documentElement.DocumentTextElement)
 378                     return children[i];
 379             }
 380             return null;
 381         }.bind(this);
 382         var _markAsCurrent = function(element) {
 383             if(element instanceof documentElement.DocumentTextElement) {
 384                 this.wrapper.find('.current-text-element').removeClass('current-text-element');
 385                 element.dom().addClass('current-text-element');
 386             } else {
 387                 this.wrapper.find('.current-node-element').removeClass('current-node-element')
 388                 element._container().addClass('current-node-element');
 389                 this.publisher('currentElementChanged', element);
 390             }
 391         }.bind(this);
 392
 393
 394         var isTextElement = element instanceof documentElement.DocumentTextElement,
 395             nodeElementToLand = isTextElement ? element.parent() : element,
 396             textElementToLand = isTextElement ? element : findFirstDirectTextChild(element, nodeElementToLand),
 397             currentTextElement = this.getCurrentTextElement(),
 398             currentNodeElement = this.getCurrentNodeElement();
 399
 400         if(currentTextElement && !(currentTextElement.sameNode(textElementToLand)))
 401             this.wrapper.find('.current-text-element').removeClass('current-text-element');
 402
 403         if(textElementToLand) {
 404             _markAsCurrent(textElementToLand);
 405             if(params.caretTo || !textElementToLand.sameNode(this.getCursor().getPosition().element))
 406                 this._moveCaretToTextElement(textElementToLand, params.caretTo); // as method on element?
 407             if(!(textElementToLand.sameNode(currentTextElement)))
 408                 this.publisher('currentTextElementSet', textElementToLand);
 409         } else {
 410             document.getSelection().removeAllRanges();
 411         }
 412
 413         if(!(currentNodeElement && currentNodeElement.sameNode(nodeElementToLand))) {
 414             _markAsCurrent(nodeElementToLand);
 415
 416             this.publisher('currentNodeElementSet', nodeElementToLand);
 417         }
 418     },
 419
 420     _moveCaretToTextElement: function(element, where) {
 421         var range = document.createRange(),
 422             node = element.dom().contents()[0];
 423
 424         if(typeof where !== 'number') {
 425             range.selectNodeContents(node);
 426         } else {
 427             range.setStart(node, where);
 428         }
 429
 430         var collapseArg = true;
 431         if(where === 'end')
 432             collapseArg = false;
 433         range.collapse(collapseArg);
 434
 435         var selection = document.getSelection();
 436
 437         selection.removeAllRanges();
 438         selection.addRange(range);
 439         this.wrapper.focus(); // FF requires this for caret to be put where range colllapses, Chrome doesn't.
 440     },
 441
 442     setCursorPosition: function(position) {
 443         if(position.element)
 444             this._moveCaretToTextElement(position.element, position.offset);
 445     },
 446
 447     toXML: function() {
 448         var parent = $('<div>'),
 449             parts = this.doc().toXML(0);
 450         parent.append(parts);
 451         return parent.html();
 452     }
 453 });
 454
 455 $.extend(Canvas.prototype.list, {
 456     create: function(params) {
 457         if(!(params.element1.parent().sameNode(params.element2.parent())))
 458             return false;
 459
 460         var parent = params.element1.parent(),
 461             canvas = params.element1.canvas;
 462
 463         if(parent.childIndex(params.element1) > parent.childIndex(params.element2)) {
 464             var tmp = params.element1;
 465             params.element1 = params.element2;
 466             params.element2 = tmp;
 467         }
 468
 469         var elementsToWrap = [];
 470
 471         var place = 'before';
 472         parent.children().some(function(element) {
 473             var _e = element;
 474             if(element.sameNode(params.element1))
 475                 place = 'inside';
 476             if(place === 'inside') {
 477                 if(element instanceof documentElement.DocumentTextElement) {
 478                     element = element.wrapWithNodeElement({tag: 'div', klass: 'list.item'});
 479                     if(element.children()[0].sameNode(params.element1))
 480                         params.element1 = element;
 481                 }
 482                 element.setWlxmlClass('item');
 483                 elementsToWrap.push(element);
 484             }
 485             if(_e.sameNode(params.element2))
 486                 return true;
 487         });
 488
 489         var listElement = canvas.createNodeElement({tag: 'div', klass: 'list-items' + (params.type === 'enum' ? '-enum' : '')});
 490         var toret;
 491         if(parent.is('list')) {
 492             var item = listElement.wrapWithNodeElement({tag: 'div', klass: 'item'});
 493             item.exec('toggleBullet', false);
 494             toret = listElement.parent();
 495         } else {
 496             toret = listElement;
 497         }
 498
 499         params.element1.before(toret);
 500
 501         elementsToWrap.forEach(function(element) {
 502             element.detach();
 503             listElement.append(element);
 504         });
 505     },
 506     extractItems: function(params) {
 507         params = _.extend({merge: true}, params);
 508         var list = params.element1.parent();
 509         if(!list.is('list') || !(list.sameNode(params.element2.parent())))
 510             return false;
 511
 512         var idx1 = list.childIndex(params.element1),
 513             idx2 = list.childIndex(params.element2),
 514             precedingItems = [],
 515             extractedItems = [],
 516             succeedingItems = [],
 517             items = list.children(),
 518             listIsNested = list.parent().getWlxmlClass() === 'item',
 519             canvas = params.element1.canvas,
 520             i;
 521
 522         if(idx1 > idx2) {
 523             var tmp = idx1; idx1 = idx2; idx2 = tmp;
 524         }
 525
 526         items.forEach(function(item, idx) {
 527             if(idx < idx1)
 528                 precedingItems.push(item);
 529             else if(idx >= idx1 && idx <= idx2) {
 530                 extractedItems.push(item);
 531             }
 532             else {
 533                 succeedingItems.push(item);
 534             }
 535         });
 536
 537         var reference = listIsNested ? list.parent() : list;
 538         if(succeedingItems.length === 0) {
 539             var reference_orig = reference;
 540             extractedItems.forEach(function(item) {
 541                 reference.after(item);
 542                 reference = item;
 543                 if(!listIsNested)
 544                     item.setWlxmlClass(null);
 545             });
 546             if(precedingItems.length === 0)
 547                 reference_orig.detach();
 548         } else if(precedingItems.length === 0) {
 549             extractedItems.forEach(function(item) {
 550                 reference.before(item);
 551                 if(!listIsNested)
 552                     item.setWlxmlClass(null);
 553             });
 554         } else {
 555             extractedItems.forEach(function(item) {
 556                 reference.after(item);
 557                 if(!listIsNested)
 558                     item.setWlxmlClass(null);
 559                 reference = item;
 560             });
 561             var secondList = canvas.createNodeElement({tag: 'div', klass:'list-items'}),
 562                 toAdd = secondList;
 563
 564             if(listIsNested) {
 565                 toAdd = secondList.wrapWithNodeElement({tag: 'div', klass:'item'});
 566             }
 567             succeedingItems.forEach(function(item) {
 568                 secondList.append(item);
 569             });
 570
 571             reference.after(toAdd);
 572         }
 573         if(!params.merge && listIsNested) {
 574             return this.extractItems({element1: extractedItems[0], element2: extractedItems[extractedItems.length-1]});
 575         }
 576         return true;
 577     },
 578     areItemsOfTheSameList: function(params) {
 579         var e1 = params.element1,
 580             e2 = params.element2;
 581         return e1.parent().sameNode(e2.parent())
 582             && e1.parent().is('list');
 583     }
 584 });
 585
 586
 587 var Cursor = function(canvas) {
 588     this.canvas = canvas;
 589 };
 590
 591 $.extend(Cursor.prototype, {
 592     isSelecting: function() {
 593         var selection = window.getSelection();
 594         return !selection.isCollapsed;
 595     },
 596     isSelectingWithinElement: function() {
 597         return this.isSelecting() && this.getSelectionStart().element.sameNode(this.getSelectionEnd().element);
 598     },
 599     isSelectingSiblings: function() {
 600         return this.isSelecting() && this.getSelectionStart().element.parent().sameNode(this.getSelectionEnd().element.parent());
 601     },
 602     getPosition: function() {
 603         return this.getSelectionAnchor();
 604     },
 605     getSelectionStart: function() {
 606         return this.getSelectionBoundry('start');
 607     },
 608     getSelectionEnd: function() {
 609         return this.getSelectionBoundry('end');
 610     },
 611     getSelectionAnchor: function() {
 612         return this.getSelectionBoundry('anchor');
 613     },
 614     getSelectionFocus: function() {
 615         return this.getSelectionBoundry('focus');
 616     },
 617     getSelectionBoundry: function(which) {
 618         var selection = window.getSelection(),
 619             anchorElement = this.canvas.getDocumentElement(selection.anchorNode),
 620             focusElement = this.canvas.getDocumentElement(selection.focusNode);
 621
 622         if((!anchorElement) || (anchorElement instanceof documentElement.DocumentNodeElement) || (!focusElement) || focusElement instanceof documentElement.DocumentNodeElement)
 623             return {};
 624
 625         if(which === 'anchor') {
 626             return {
 627                 element: anchorElement,
 628                 offset: selection.anchorOffset,
 629                 offsetAtBeginning: selection.anchorOffset === 0,
 630                 offsetAtEnd: selection.anchorNode.data.length === selection.anchorOffset
 631             };
 632         }
 633         if(which === 'focus') {
 634             return {
 635                 element: focusElement,
 636                 offset: selection.focusOffset,
 637                 offsetAtBeginning: selection.focusOffset === 0,
 638                 offsetAtEnd: selection.focusNode.data.length === selection.focusOffset
 639             };
 640         }
 641
 642         var element,
 643             offset;
 644
 645         if(anchorElement.parent().sameNode(focusElement.parent())) {
 646             var parent = anchorElement.parent(),
 647                 anchorFirst = parent.childIndex(anchorElement) < parent.childIndex(focusElement);
 648             if(anchorFirst) {
 649                 if(which === 'start') {
 650                     element = anchorElement;
 651                     offset = selection.anchorOffset
 652                 }
 653                 else if(which === 'end') {
 654                     element = focusElement,
 655                     offset = selection.focusOffset
 656                 }
 657             } else {
 658                 if(which === 'start') {
 659                     element = focusElement,
 660                     offset = selection.focusOffset
 661                 }
 662                 else if(which === 'end') {
 663                     element = anchorElement;
 664                     offset = selection.anchorOffset
 665                 }
 666             }
 667         } else {
 668             // TODO: Handle order via https://developer.mozilla.org/en-US/docs/Web/API/Node.compareDocumentPosition
 669             if(which === 'start') {
 670                 element = anchorElement;
 671                 offset = selection.anchorOffset
 672             } else {
 673                 element = focusElement;
 674                 offset = selection.focusOffset
 675             }
 676         }
 677
 678         var nodeLen = (element.sameNode(focusElement) ? selection.focusNode : selection.anchorNode).length;
 679         return {
 680             element: element,
 681             offset: offset,
 682             offsetAtBeginning: offset === 0,
 683             offsetAtEnd: nodeLen === offset
 684         }
 685     }
 686 })
 687
 688 return {
 689     fromXML: function(xml, publisher) {
 690         return new Canvas(xml, publisher);
 691     },
 692     fromXML2: function(wlxmlNode, publisher) {
 693         return new Canvas(wlxmlNode, publisher, 2);
 694     }
 695 };
 696
 697 });