Scriptaculous/DragDrop.js

   1 // Copyright (c) 2005-2007 Thomas Fuchs (http://script.aculo.us, http://mir.aculo.us)
   2 //           (c) 2005-2007 Sammi Williams (http://www.oriontransfer.co.nz, sammi@oriontransfer.co.nz)
   3 //
   4 // script.aculo.us is freely distributable under the terms of an MIT-style license.
   5 // For details, see the script.aculo.us web site: http://script.aculo.us/
   6
   7 JSAN.use('Prototype');
   8 JSAN.use('Scriptaculous.Effects');
   9
  10 if(Object.isUndefined(Effect))
  11   throw("DragDrop.js requires including script.aculo.us' Effects.js library");
  12
  13 var Droppables = {
  14   drops: [],
  15
  16   remove: function(element) {
  17     this.drops = this.drops.reject(function(d) { return d.element==$(element) });
  18   },
  19
  20   add: function(element) {
  21     element = $(element);
  22     var options = Object.extend({
  23       greedy:     true,
  24       hoverclass: null,
  25       tree:       false
  26     }, arguments[1] || { });
  27
  28     // cache containers
  29     if(options.containment) {
  30       options._containers = [];
  31       var containment = options.containment;
  32       if(Object.isArray(containment)) {
  33         containment.each( function(c) { options._containers.push($(c)) });
  34       } else {
  35         options._containers.push($(containment));
  36       }
  37     }
  38
  39     if(options.accept) options.accept = [options.accept].flatten();
  40
  41     Element.makePositioned(element); // fix IE
  42     options.element = element;
  43
  44     this.drops.push(options);
  45   },
  46
  47   findDeepestChild: function(drops) {
  48     deepest = drops[0];
  49
  50     for (i = 1; i < drops.length; ++i)
  51       if (Element.isParent(drops[i].element, deepest.element))
  52         deepest = drops[i];
  53
  54     return deepest;
  55   },
  56
  57   isContained: function(element, drop) {
  58     var containmentNode;
  59     if(drop.tree) {
  60       containmentNode = element.treeNode;
  61     } else {
  62       containmentNode = element.parentNode;
  63     }
  64     return drop._containers.detect(function(c) { return containmentNode == c });
  65   },
  66
  67   isAffected: function(point, element, drop) {
  68     return (
  69       (drop.element!=element) &&
  70       ((!drop._containers) ||
  71         this.isContained(element, drop)) &&
  72       ((!drop.accept) ||
  73         (Element.classNames(element).detect(
  74           function(v) { return drop.accept.include(v) } ) )) &&
  75       Position.within(drop.element, point[0], point[1]) );
  76   },
  77
  78   deactivate: function(drop) {
  79     if(drop.hoverclass)
  80       Element.removeClassName(drop.element, drop.hoverclass);
  81     this.last_active = null;
  82   },
  83
  84   activate: function(drop) {
  85     if(drop.hoverclass)
  86       Element.addClassName(drop.element, drop.hoverclass);
  87     this.last_active = drop;
  88   },
  89
  90   show: function(point, element) {
  91     if(!this.drops.length) return;
  92     var drop, affected = [];
  93
  94     this.drops.each( function(drop) {
  95       if(Droppables.isAffected(point, element, drop))
  96         affected.push(drop);
  97     });
  98
  99     if(affected.length>0)
 100       drop = Droppables.findDeepestChild(affected);
 101
 102     if(this.last_active && this.last_active != drop) this.deactivate(this.last_active);
 103     if (drop) {
 104       Position.within(drop.element, point[0], point[1]);
 105       if(drop.onHover)
 106         drop.onHover(element, drop.element, Position.overlap(drop.overlap, drop.element));
 107
 108       if (drop != this.last_active) Droppables.activate(drop);
 109     }
 110   },
 111
 112   fire: function(event, element) {
 113     if(!this.last_active) return;
 114     Position.prepare();
 115
 116     if (this.isAffected([Event.pointerX(event), Event.pointerY(event)], element, this.last_active))
 117       if (this.last_active.onDrop) {
 118         this.last_active.onDrop(element, this.last_active.element, event);
 119         return true;
 120       }
 121   },
 122
 123   reset: function() {
 124     if(this.last_active)
 125       this.deactivate(this.last_active);
 126   }
 127 }
 128
 129 var Draggables = {
 130   drags: [],
 131   observers: [],
 132
 133   register: function(draggable) {
 134     if(this.drags.length == 0) {
 135       this.eventMouseUp   = this.endDrag.bindAsEventListener(this);
 136       this.eventMouseMove = this.updateDrag.bindAsEventListener(this);
 137       this.eventKeypress  = this.keyPress.bindAsEventListener(this);
 138
 139       Event.observe(document, "mouseup", this.eventMouseUp);
 140       Event.observe(document, "mousemove", this.eventMouseMove);
 141       Event.observe(document, "keypress", this.eventKeypress);
 142     }
 143     this.drags.push(draggable);
 144   },
 145
 146   unregister: function(draggable) {
 147     this.drags = this.drags.reject(function(d) { return d==draggable });
 148     if(this.drags.length == 0) {
 149       Event.stopObserving(document, "mouseup", this.eventMouseUp);
 150       Event.stopObserving(document, "mousemove", this.eventMouseMove);
 151       Event.stopObserving(document, "keypress", this.eventKeypress);
 152     }
 153   },
 154
 155   activate: function(draggable) {
 156     if(draggable.options.delay) {
 157       this._timeout = setTimeout(function() {
 158         Draggables._timeout = null;
 159         window.focus();
 160         Draggables.activeDraggable = draggable;
 161       }.bind(this), draggable.options.delay);
 162     } else {
 163       window.focus(); // allows keypress events if window isn't currently focused, fails for Safari
 164       this.activeDraggable = draggable;
 165     }
 166   },
 167
 168   deactivate: function() {
 169     this.activeDraggable = null;
 170   },
 171
 172   updateDrag: function(event) {
 173     if(!this.activeDraggable) return;
 174     var pointer = [Event.pointerX(event), Event.pointerY(event)];
 175     // Mozilla-based browsers fire successive mousemove events with
 176     // the same coordinates, prevent needless redrawing (moz bug?)
 177     if(this._lastPointer && (this._lastPointer.inspect() == pointer.inspect())) return;
 178     this._lastPointer = pointer;
 179
 180     this.activeDraggable.updateDrag(event, pointer);
 181   },
 182
 183   endDrag: function(event) {
 184     if(this._timeout) {
 185       clearTimeout(this._timeout);
 186       this._timeout = null;
 187     }
 188     if(!this.activeDraggable) return;
 189     this._lastPointer = null;
 190     this.activeDraggable.endDrag(event);
 191     this.activeDraggable = null;
 192   },
 193
 194   keyPress: function(event) {
 195     if(this.activeDraggable)
 196       this.activeDraggable.keyPress(event);
 197   },
 198
 199   addObserver: function(observer) {
 200     this.observers.push(observer);
 201     this._cacheObserverCallbacks();
 202   },
 203
 204   removeObserver: function(element) {  // element instead of observer fixes mem leaks
 205     this.observers = this.observers.reject( function(o) { return o.element==element });
 206     this._cacheObserverCallbacks();
 207   },
 208
 209   notify: function(eventName, draggable, event) {  // 'onStart', 'onEnd', 'onDrag'
 210     if(this[eventName+'Count'] > 0)
 211       this.observers.each( function(o) {
 212         if(o[eventName]) o[eventName](eventName, draggable, event);
 213       });
 214     if(draggable.options[eventName]) draggable.options[eventName](draggable, event);
 215   },
 216
 217   _cacheObserverCallbacks: function() {
 218     ['onStart','onEnd','onDrag'].each( function(eventName) {
 219       Draggables[eventName+'Count'] = Draggables.observers.select(
 220         function(o) { return o[eventName]; }
 221       ).length;
 222     });
 223   }
 224 }
 225
 226 /*--------------------------------------------------------------------------*/
 227
 228 var Draggable = Class.create({
 229   initialize: function(element) {
 230     var defaults = {
 231       handle: false,
 232       reverteffect: function(element, top_offset, left_offset) {
 233         var dur = Math.sqrt(Math.abs(top_offset^2)+Math.abs(left_offset^2))*0.02;
 234         new Effect.Move(element, { x: -left_offset, y: -top_offset, duration: dur,
 235           queue: {scope:'_draggable', position:'end'}
 236         });
 237       },
 238       endeffect: function(element) {
 239         var toOpacity = Object.isNumber(element._opacity) ? element._opacity : 1.0;
 240         new Effect.Opacity(element, {duration:0.2, from:0.7, to:toOpacity,
 241           queue: {scope:'_draggable', position:'end'},
 242           afterFinish: function(){
 243             Draggable._dragging[element] = false
 244           }
 245         });
 246       },
 247       zindex: 1000,
 248       revert: false,
 249       quiet: false,
 250       scroll: false,
 251       scrollSensitivity: 20,
 252       scrollSpeed: 15,
 253       snap: false,  // false, or xy or [x,y] or function(x,y){ return [x,y] }
 254       delay: 0
 255     };
 256
 257     if(!arguments[1] || Object.isUndefined(arguments[1].endeffect))
 258       Object.extend(defaults, {
 259         starteffect: function(element) {
 260           element._opacity = Element.getOpacity(element);
 261           Draggable._dragging[element] = true;
 262           new Effect.Opacity(element, {duration:0.2, from:element._opacity, to:0.7});
 263         }
 264       });
 265
 266     var options = Object.extend(defaults, arguments[1] || { });
 267
 268     this.element = $(element);
 269
 270     if(options.handle && Object.isString(options.handle))
 271       this.handle = this.element.down('.'+options.handle, 0);
 272
 273     if(!this.handle) this.handle = $(options.handle);
 274     if(!this.handle) this.handle = this.element;
 275
 276     if(options.scroll && !options.scroll.scrollTo && !options.scroll.outerHTML) {
 277       options.scroll = $(options.scroll);
 278       this._isScrollChild = Element.childOf(this.element, options.scroll);
 279     }
 280
 281     Element.makePositioned(this.element); // fix IE
 282
 283     this.options  = options;
 284     this.dragging = false;
 285
 286     this.eventMouseDown = this.initDrag.bindAsEventListener(this);
 287     Event.observe(this.handle, "mousedown", this.eventMouseDown);
 288
 289     Draggables.register(this);
 290   },
 291
 292   destroy: function() {
 293     Event.stopObserving(this.handle, "mousedown", this.eventMouseDown);
 294     Draggables.unregister(this);
 295   },
 296
 297   currentDelta: function() {
 298     return([
 299       parseInt(Element.getStyle(this.element,'left') || '0'),
 300       parseInt(Element.getStyle(this.element,'top') || '0')]);
 301   },
 302
 303   initDrag: function(event) {
 304     if(!Object.isUndefined(Draggable._dragging[this.element]) &&
 305       Draggable._dragging[this.element]) return;
 306     if(Event.isLeftClick(event)) {
 307       // abort on form elements, fixes a Firefox issue
 308       var src = Event.element(event);
 309       if((tag_name = src.tagName.toUpperCase()) && (
 310         tag_name=='INPUT' ||
 311         tag_name=='SELECT' ||
 312         tag_name=='OPTION' ||
 313         tag_name=='BUTTON' ||
 314         tag_name=='TEXTAREA')) return;
 315
 316       var pointer = [Event.pointerX(event), Event.pointerY(event)];
 317       var pos     = Position.cumulativeOffset(this.element);
 318       this.offset = [0,1].map( function(i) { return (pointer[i] - pos[i]) });
 319
 320       Draggables.activate(this);
 321       Event.stop(event);
 322     }
 323   },
 324
 325   startDrag: function(event) {
 326     this.dragging = true;
 327     if(!this.delta)
 328       this.delta = this.currentDelta();
 329
 330     if(this.options.zindex) {
 331       this.originalZ = parseInt(Element.getStyle(this.element,'z-index') || 0);
 332       this.element.style.zIndex = this.options.zindex;
 333     }
 334
 335     if(this.options.ghosting) {
 336       this._clone = this.element.cloneNode(true);
 337       this.element._originallyAbsolute = (this.element.getStyle('position') == 'absolute');
 338       if (!this.element._originallyAbsolute)
 339         Position.absolutize(this.element);
 340       this.element.parentNode.insertBefore(this._clone, this.element);
 341     }
 342
 343     if(this.options.scroll) {
 344       if (this.options.scroll == window) {
 345         var where = this._getWindowScroll(this.options.scroll);
 346         this.originalScrollLeft = where.left;
 347         this.originalScrollTop = where.top;
 348       } else {
 349         this.originalScrollLeft = this.options.scroll.scrollLeft;
 350         this.originalScrollTop = this.options.scroll.scrollTop;
 351       }
 352     }
 353
 354     Draggables.notify('onStart', this, event);
 355
 356     if(this.options.starteffect) this.options.starteffect(this.element);
 357   },
 358
 359   updateDrag: function(event, pointer) {
 360     if(!this.dragging) this.startDrag(event);
 361
 362     if(!this.options.quiet){
 363       Position.prepare();
 364       Droppables.show(pointer, this.element);
 365     }
 366
 367     Draggables.notify('onDrag', this, event);
 368
 369     this.draw(pointer);
 370     if(this.options.change) this.options.change(this);
 371
 372     if(this.options.scroll) {
 373       this.stopScrolling();
 374
 375       var p;
 376       if (this.options.scroll == window) {
 377         with(this._getWindowScroll(this.options.scroll)) { p = [ left, top, left+width, top+height ]; }
 378       } else {
 379         p = Position.page(this.options.scroll);
 380         p[0] += this.options.scroll.scrollLeft + Position.deltaX;
 381         p[1] += this.options.scroll.scrollTop + Position.deltaY;
 382         p.push(p[0]+this.options.scroll.offsetWidth);
 383         p.push(p[1]+this.options.scroll.offsetHeight);
 384       }
 385       var speed = [0,0];
 386       if(pointer[0] < (p[0]+this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[0]+this.options.scrollSensitivity);
 387       if(pointer[1] < (p[1]+this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[1]+this.options.scrollSensitivity);
 388       if(pointer[0] > (p[2]-this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[2]-this.options.scrollSensitivity);
 389       if(pointer[1] > (p[3]-this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[3]-this.options.scrollSensitivity);
 390       this.startScrolling(speed);
 391     }
 392
 393     // fix AppleWebKit rendering
 394     if(Prototype.Browser.WebKit) window.scrollBy(0,0);
 395
 396     Event.stop(event);
 397   },
 398
 399   finishDrag: function(event, success) {
 400     this.dragging = false;
 401
 402     if(this.options.quiet){
 403       Position.prepare();
 404       var pointer = [Event.pointerX(event), Event.pointerY(event)];
 405       Droppables.show(pointer, this.element);
 406     }
 407
 408     if(this.options.ghosting) {
 409       if (!this.element._originallyAbsolute)
 410         Position.relativize(this.element);
 411       delete this.element._originallyAbsolute;
 412       Element.remove(this._clone);
 413       this._clone = null;
 414     }
 415
 416     var dropped = false;
 417     if(success) {
 418       dropped = Droppables.fire(event, this.element);
 419       if (!dropped) dropped = false;
 420     }
 421     if(dropped && this.options.onDropped) this.options.onDropped(this.element);
 422     Draggables.notify('onEnd', this, event);
 423
 424     var revert = this.options.revert;
 425     if(revert && Object.isFunction(revert)) revert = revert(this.element);
 426
 427     var d = this.currentDelta();
 428     if(revert && this.options.reverteffect) {
 429       if (dropped == 0 || revert != 'failure')
 430         this.options.reverteffect(this.element,
 431           d[1]-this.delta[1], d[0]-this.delta[0]);
 432     } else {
 433       this.delta = d;
 434     }
 435
 436     if(this.options.zindex)
 437       this.element.style.zIndex = this.originalZ;
 438
 439     if(this.options.endeffect)
 440       this.options.endeffect(this.element);
 441
 442     Draggables.deactivate(this);
 443     Droppables.reset();
 444   },
 445
 446   keyPress: function(event) {
 447     if(event.keyCode!=Event.KEY_ESC) return;
 448     this.finishDrag(event, false);
 449     Event.stop(event);
 450   },
 451
 452   endDrag: function(event) {
 453     if(!this.dragging) return;
 454     this.stopScrolling();
 455     this.finishDrag(event, true);
 456     Event.stop(event);
 457   },
 458
 459   draw: function(point) {
 460     var pos = Position.cumulativeOffset(this.element);
 461     if(this.options.ghosting) {
 462       var r   = Position.realOffset(this.element);
 463       pos[0] += r[0] - Position.deltaX; pos[1] += r[1] - Position.deltaY;
 464     }
 465
 466     var d = this.currentDelta();
 467     pos[0] -= d[0]; pos[1] -= d[1];
 468
 469     if(this.options.scroll && (this.options.scroll != window && this._isScrollChild)) {
 470       pos[0] -= this.options.scroll.scrollLeft-this.originalScrollLeft;
 471       pos[1] -= this.options.scroll.scrollTop-this.originalScrollTop;
 472     }
 473
 474     var p = [0,1].map(function(i){
 475       return (point[i]-pos[i]-this.offset[i])
 476     }.bind(this));
 477
 478     if(this.options.snap) {
 479       if(Object.isFunction(this.options.snap)) {
 480         p = this.options.snap(p[0],p[1],this);
 481       } else {
 482       if(Object.isArray(this.options.snap)) {
 483         p = p.map( function(v, i) {
 484           return (v/this.options.snap[i]).round()*this.options.snap[i] }.bind(this))
 485       } else {
 486         p = p.map( function(v) {
 487           return (v/this.options.snap).round()*this.options.snap }.bind(this))
 488       }
 489     }}
 490
 491     var style = this.element.style;
 492     if((!this.options.constraint) || (this.options.constraint=='horizontal'))
 493       style.left = p[0] + "px";
 494     if((!this.options.constraint) || (this.options.constraint=='vertical')){
 495       style.top  = p[1] + "px";
 496          }
 497
 498     if(style.visibility=="hidden") style.visibility = ""; // fix gecko rendering
 499   },
 500
 501   stopScrolling: function() {
 502     if(this.scrollInterval) {
 503       clearInterval(this.scrollInterval);
 504       this.scrollInterval = null;
 505       Draggables._lastScrollPointer = null;
 506     }
 507   },
 508
 509   startScrolling: function(speed) {
 510     if(!(speed[0] || speed[1])) return;
 511     this.scrollSpeed = [speed[0]*this.options.scrollSpeed,speed[1]*this.options.scrollSpeed];
 512     this.lastScrolled = new Date();
 513     this.scrollInterval = setInterval(this.scroll.bind(this), 10);
 514   },
 515
 516   scroll: function() {
 517     var current = new Date();
 518     var delta = current - this.lastScrolled;
 519     this.lastScrolled = current;
 520     if(this.options.scroll == window) {
 521       with (this._getWindowScroll(this.options.scroll)) {
 522         if (this.scrollSpeed[0] || this.scrollSpeed[1]) {
 523           var d = delta / 1000;
 524           this.options.scroll.scrollTo( left + d*this.scrollSpeed[0], top + d*this.scrollSpeed[1] );
 525         }
 526       }
 527     } else {
 528       this.options.scroll.scrollLeft += this.scrollSpeed[0] * delta / 1000;
 529       this.options.scroll.scrollTop  += this.scrollSpeed[1] * delta / 1000;
 530     }
 531
 532     Position.prepare();
 533     Droppables.show(Draggables._lastPointer, this.element);
 534     Draggables.notify('onDrag', this);
 535     if (this._isScrollChild) {
 536       Draggables._lastScrollPointer = Draggables._lastScrollPointer || $A(Draggables._lastPointer);
 537       Draggables._lastScrollPointer[0] += this.scrollSpeed[0] * delta / 1000;
 538       Draggables._lastScrollPointer[1] += this.scrollSpeed[1] * delta / 1000;
 539       if (Draggables._lastScrollPointer[0] < 0)
 540         Draggables._lastScrollPointer[0] = 0;
 541       if (Draggables._lastScrollPointer[1] < 0)
 542         Draggables._lastScrollPointer[1] = 0;
 543       this.draw(Draggables._lastScrollPointer);
 544     }
 545
 546     if(this.options.change) this.options.change(this);
 547   },
 548
 549   _getWindowScroll: function(w) {
 550     var T, L, W, H;
 551     with (w.document) {
 552       if (w.document.documentElement && documentElement.scrollTop) {
 553         T = documentElement.scrollTop;
 554         L = documentElement.scrollLeft;
 555       } else if (w.document.body) {
 556         T = body.scrollTop;
 557         L = body.scrollLeft;
 558       }
 559       if (w.innerWidth) {
 560         W = w.innerWidth;
 561         H = w.innerHeight;
 562       } else if (w.document.documentElement && documentElement.clientWidth) {
 563         W = documentElement.clientWidth;
 564         H = documentElement.clientHeight;
 565       } else {
 566         W = body.offsetWidth;
 567         H = body.offsetHeight
 568       }
 569     }
 570     return { top: T, left: L, width: W, height: H };
 571   }
 572 });
 573
 574 Draggable._dragging = { };
 575
 576 /*--------------------------------------------------------------------------*/
 577
 578 var SortableObserver = Class.create({
 579   initialize: function(element, observer) {
 580     this.element   = $(element);
 581     this.observer  = observer;
 582     this.lastValue = Sortable.serialize(this.element);
 583   },
 584
 585   onStart: function() {
 586     this.lastValue = Sortable.serialize(this.element);
 587   },
 588
 589   onEnd: function() {
 590     Sortable.unmark();
 591     if(this.lastValue != Sortable.serialize(this.element))
 592       this.observer(this.element)
 593   }
 594 });
 595
 596 var Sortable = {
 597   SERIALIZE_RULE: /^[^_\-](?:[A-Za-z0-9\-\_]*)[_](.*)$/,
 598
 599   sortables: { },
 600
 601   _findRootElement: function(element) {
 602     while (element.tagName.toUpperCase() != "BODY") {
 603       if(element.id && Sortable.sortables[element.id]) return element;
 604       element = element.parentNode;
 605     }
 606   },
 607
 608   options: function(element) {
 609     element = Sortable._findRootElement($(element));
 610     if(!element) return;
 611     return Sortable.sortables[element.id];
 612   },
 613
 614   destroy: function(element){
 615     var s = Sortable.options(element);
 616
 617     if(s) {
 618       Draggables.removeObserver(s.element);
 619       s.droppables.each(function(d){ Droppables.remove(d) });
 620       s.draggables.invoke('destroy');
 621
 622       delete Sortable.sortables[s.element.id];
 623     }
 624   },
 625
 626   create: function(element) {
 627     element = $(element);
 628     var options = Object.extend({
 629       element:     element,
 630       tag:         'li',       // assumes li children, override with tag: 'tagname'
 631       dropOnEmpty: false,
 632       tree:        false,
 633       treeTag:     'ul',
 634       overlap:     'vertical', // one of 'vertical', 'horizontal'
 635       constraint:  'vertical', // one of 'vertical', 'horizontal', false
 636       containment: element,    // also takes array of elements (or id's); or false
 637       handle:      false,      // or a CSS class
 638       only:        false,
 639       delay:       0,
 640       hoverclass:  null,
 641       ghosting:    false,
 642       quiet:       false,
 643       scroll:      false,
 644       scrollSensitivity: 20,
 645       scrollSpeed: 15,
 646       format:      this.SERIALIZE_RULE,
 647
 648       // these take arrays of elements or ids and can be
 649       // used for better initialization performance
 650       elements:    false,
 651       handles:     false,
 652
 653       onChange:    Prototype.emptyFunction,
 654       onUpdate:    Prototype.emptyFunction
 655     }, arguments[1] || { });
 656
 657     // clear any old sortable with same element
 658     this.destroy(element);
 659
 660     // build options for the draggables
 661     var options_for_draggable = {
 662       revert:      true,
 663       quiet:       options.quiet,
 664       scroll:      options.scroll,
 665       scrollSpeed: options.scrollSpeed,
 666       scrollSensitivity: options.scrollSensitivity,
 667       delay:       options.delay,
 668       ghosting:    options.ghosting,
 669       constraint:  options.constraint,
 670       handle:      options.handle };
 671
 672     if(options.starteffect)
 673       options_for_draggable.starteffect = options.starteffect;
 674
 675     if(options.reverteffect)
 676       options_for_draggable.reverteffect = options.reverteffect;
 677     else
 678       if(options.ghosting) options_for_draggable.reverteffect = function(element) {
 679         element.style.top  = 0;
 680         element.style.left = 0;
 681       };
 682
 683     if(options.endeffect)
 684       options_for_draggable.endeffect = options.endeffect;
 685
 686     if(options.zindex)
 687       options_for_draggable.zindex = options.zindex;
 688
 689     // build options for the droppables
 690     var options_for_droppable = {
 691       overlap:     options.overlap,
 692       containment: options.containment,
 693       tree:        options.tree,
 694       hoverclass:  options.hoverclass,
 695       onHover:     Sortable.onHover
 696     }
 697
 698     var options_for_tree = {
 699       onHover:      Sortable.onEmptyHover,
 700       overlap:      options.overlap,
 701       containment:  options.containment,
 702       hoverclass:   options.hoverclass
 703     }
 704
 705     // fix for gecko engine
 706     Element.cleanWhitespace(element);
 707
 708     options.draggables = [];
 709     options.droppables = [];
 710
 711     // drop on empty handling
 712     if(options.dropOnEmpty || options.tree) {
 713       Droppables.add(element, options_for_tree);
 714       options.droppables.push(element);
 715     }
 716
 717     (options.elements || this.findElements(element, options) || []).each( function(e,i) {
 718       var handle = options.handles ? $(options.handles[i]) :
 719         (options.handle ? $(e).select('.' + options.handle)[0] : e);
 720       options.draggables.push(
 721         new Draggable(e, Object.extend(options_for_draggable, { handle: handle })));
 722       Droppables.add(e, options_for_droppable);
 723       if(options.tree) e.treeNode = element;
 724       options.droppables.push(e);
 725     });
 726
 727     if(options.tree) {
 728       (Sortable.findTreeElements(element, options) || []).each( function(e) {
 729         Droppables.add(e, options_for_tree);
 730         e.treeNode = element;
 731         options.droppables.push(e);
 732       });
 733     }
 734
 735     // keep reference
 736     this.sortables[element.id] = options;
 737
 738     // for onupdate
 739     Draggables.addObserver(new SortableObserver(element, options.onUpdate));
 740
 741   },
 742
 743   // return all suitable-for-sortable elements in a guaranteed order
 744   findElements: function(element, options) {
 745     return Element.findChildren(
 746       element, options.only, options.tree ? true : false, options.tag);
 747   },
 748
 749   findTreeElements: function(element, options) {
 750     return Element.findChildren(
 751       element, options.only, options.tree ? true : false, options.treeTag);
 752   },
 753
 754   onHover: function(element, dropon, overlap) {
 755     if(Element.isParent(dropon, element)) return;
 756
 757     if(overlap > .33 && overlap < .66 && Sortable.options(dropon).tree) {
 758       return;
 759     } else if(overlap>0.5) {
 760       Sortable.mark(dropon, 'before');
 761       if(dropon.previousSibling != element) {
 762         var oldParentNode = element.parentNode;
 763         element.style.visibility = "hidden"; // fix gecko rendering
 764         dropon.parentNode.insertBefore(element, dropon);
 765         if(dropon.parentNode!=oldParentNode)
 766           Sortable.options(oldParentNode).onChange(element);
 767         Sortable.options(dropon.parentNode).onChange(element);
 768       }
 769     } else {
 770       Sortable.mark(dropon, 'after');
 771       var nextElement = dropon.nextSibling || null;
 772       if(nextElement != element) {
 773         var oldParentNode = element.parentNode;
 774         element.style.visibility = "hidden"; // fix gecko rendering
 775         dropon.parentNode.insertBefore(element, nextElement);
 776         if(dropon.parentNode!=oldParentNode)
 777           Sortable.options(oldParentNode).onChange(element);
 778         Sortable.options(dropon.parentNode).onChange(element);
 779       }
 780     }
 781   },
 782
 783   onEmptyHover: function(element, dropon, overlap) {
 784     var oldParentNode = element.parentNode;
 785     var droponOptions = Sortable.options(dropon);
 786
 787     if(!Element.isParent(dropon, element)) {
 788       var index;
 789
 790       var children = Sortable.findElements(dropon, {tag: droponOptions.tag, only: droponOptions.only});
 791       var child = null;
 792
 793       if(children) {
 794         var offset = Element.offsetSize(dropon, droponOptions.overlap) * (1.0 - overlap);
 795
 796         for (index = 0; index < children.length; index += 1) {
 797           if (offset - Element.offsetSize (children[index], droponOptions.overlap) >= 0) {
 798             offset -= Element.offsetSize (children[index], droponOptions.overlap);
 799           } else if (offset - (Element.offsetSize (children[index], droponOptions.overlap) / 2) >= 0) {
 800             child = index + 1 < children.length ? children[index + 1] : null;
 801             break;
 802           } else {
 803             child = children[index];
 804             break;
 805           }
 806         }
 807       }
 808
 809       dropon.insertBefore(element, child);
 810
 811       Sortable.options(oldParentNode).onChange(element);
 812       droponOptions.onChange(element);
 813     }
 814   },
 815
 816   unmark: function() {
 817     if(Sortable._marker) Sortable._marker.hide();
 818   },
 819
 820   mark: function(dropon, position) {
 821     // mark on ghosting only
 822     var sortable = Sortable.options(dropon.parentNode);
 823     if(sortable && !sortable.ghosting) return;
 824
 825     if(!Sortable._marker) {
 826       Sortable._marker =
 827         ($('dropmarker') || Element.extend(document.createElement('DIV'))).
 828           hide().addClassName('dropmarker').setStyle({position:'absolute'});
 829       document.getElementsByTagName("body").item(0).appendChild(Sortable._marker);
 830     }
 831     var offsets = Position.cumulativeOffset(dropon);
 832     Sortable._marker.setStyle({left: offsets[0]+'px', top: offsets[1] + 'px'});
 833
 834     if(position=='after')
 835       if(sortable.overlap == 'horizontal')
 836         Sortable._marker.setStyle({left: (offsets[0]+dropon.clientWidth) + 'px'});
 837       else
 838         Sortable._marker.setStyle({top: (offsets[1]+dropon.clientHeight) + 'px'});
 839
 840     Sortable._marker.show();
 841   },
 842
 843   _tree: function(element, options, parent) {
 844     var children = Sortable.findElements(element, options) || [];
 845
 846     for (var i = 0; i < children.length; ++i) {
 847       var match = children[i].id.match(options.format);
 848
 849       if (!match) continue;
 850
 851       var child = {
 852         id: encodeURIComponent(match ? match[1] : null),
 853         element: element,
 854         parent: parent,
 855         children: [],
 856         position: parent.children.length,
 857         container: $(children[i]).down(options.treeTag)
 858       }
 859
 860       /* Get the element containing the children and recurse over it */
 861       if (child.container)
 862         this._tree(child.container, options, child)
 863
 864       parent.children.push (child);
 865     }
 866
 867     return parent;
 868   },
 869
 870   tree: function(element) {
 871     element = $(element);
 872     var sortableOptions = this.options(element);
 873     var options = Object.extend({
 874       tag: sortableOptions.tag,
 875       treeTag: sortableOptions.treeTag,
 876       only: sortableOptions.only,
 877       name: element.id,
 878       format: sortableOptions.format
 879     }, arguments[1] || { });
 880
 881     var root = {
 882       id: null,
 883       parent: null,
 884       children: [],
 885       container: element,
 886       position: 0
 887     }
 888
 889     return Sortable._tree(element, options, root);
 890   },
 891
 892   /* Construct a [i] index for a particular node */
 893   _constructIndex: function(node) {
 894     var index = '';
 895     do {
 896       if (node.id) index = '[' + node.position + ']' + index;
 897     } while ((node = node.parent) != null);
 898     return index;
 899   },
 900
 901   sequence: function(element) {
 902     element = $(element);
 903     var options = Object.extend(this.options(element), arguments[1] || { });
 904
 905     return $(this.findElements(element, options) || []).map( function(item) {
 906       return item.id.match(options.format) ? item.id.match(options.format)[1] : '';
 907     });
 908   },
 909
 910   setSequence: function(element, new_sequence) {
 911     element = $(element);
 912     var options = Object.extend(this.options(element), arguments[2] || { });
 913
 914     var nodeMap = { };
 915     this.findElements(element, options).each( function(n) {
 916         if (n.id.match(options.format))
 917             nodeMap[n.id.match(options.format)[1]] = [n, n.parentNode];
 918         n.parentNode.removeChild(n);
 919     });
 920
 921     new_sequence.each(function(ident) {
 922       var n = nodeMap[ident];
 923       if (n) {
 924         n[1].appendChild(n[0]);
 925         delete nodeMap[ident];
 926       }
 927     });
 928   },
 929
 930   serialize: function(element) {
 931     element = $(element);
 932     var options = Object.extend(Sortable.options(element), arguments[1] || { });
 933     var name = encodeURIComponent(
 934       (arguments[1] && arguments[1].name) ? arguments[1].name : element.id);
 935
 936     if (options.tree) {
 937       return Sortable.tree(element, arguments[1]).children.map( function (item) {
 938         return [name + Sortable._constructIndex(item) + "[id]=" +
 939                 encodeURIComponent(item.id)].concat(item.children.map(arguments.callee));
 940       }).flatten().join('&');
 941     } else {
 942       return Sortable.sequence(element, arguments[1]).map( function(item) {
 943         return name + "[]=" + encodeURIComponent(item);
 944       }).join('&');
 945     }
 946   }
 947 }
 948
 949 // Returns true if child is contained within element
 950 Element.isParent = function(child, element) {
 951   if (!child.parentNode || child == element) return false;
 952   if (child.parentNode == element) return true;
 953   return Element.isParent(child.parentNode, element);
 954 }
 955
 956 Element.findChildren = function(element, only, recursive, tagName) {
 957   if(!element.hasChildNodes()) return null;
 958   tagName = tagName.toUpperCase();
 959   if(only) only = [only].flatten();
 960   var elements = [];
 961   $A(element.childNodes).each( function(e) {
 962     if(e.tagName && e.tagName.toUpperCase()==tagName &&
 963       (!only || (Element.classNames(e).detect(function(v) { return only.include(v) }))))
 964         elements.push(e);
 965     if(recursive) {
 966       var grandchildren = Element.findChildren(e, only, recursive, tagName);
 967       if(grandchildren) elements.push(grandchildren);
 968     }
 969   });
 970
 971   return (elements.length>0 ? elements.flatten() : []);
 972 }
 973
 974 Element.offsetSize = function (element, type) {
 975   return element['offset' + ((type=='vertical' || type=='height') ? 'Height' : 'Width')];
 976 }