public/js/dragdrop.js

   1 // script.aculo.us dragdrop.js v1.9.0, Thu Dec 23 16:54:48 -0500 2010
   2
   3 // Copyright (c) 2005-2010 Thomas Fuchs (http://script.aculo.us, http://mir.aculo.us)
   4 //
   5 // script.aculo.us is freely distributable under the terms of an MIT-style license.
   6 // For details, see the script.aculo.us web site: http://script.aculo.us/
   7
   8 if(Object.isUndefined(Effect))
   9   throw("dragdrop.js requires including script.aculo.us' effects.js library");
  10
  11 var Droppables = {
  12   drops: [],
  13
  14   remove: function(element) {
  15     this.drops = this.drops.reject(function(d) { return d.element==$(element) });
  16   },
  17
  18   add: function(element) {
  19     element = $(element);
  20     var options = Object.extend({
  21       greedy:     true,
  22       hoverclass: null,
  23       tree:       false
  24     }, arguments[1] || { });
  25
  26     // cache containers
  27     if(options.containment) {
  28       options._containers = [];
  29       var containment = options.containment;
  30       if(Object.isArray(containment)) {
  31         containment.each( function(c) { options._containers.push($(c)) });
  32       } else {
  33         options._containers.push($(containment));
  34       }
  35     }
  36
  37     if(options.accept) options.accept = [options.accept].flatten();
  38
  39     Element.makePositioned(element); // fix IE
  40     options.element = element;
  41
  42     this.drops.push(options);
  43   },
  44
  45   findDeepestChild: function(drops) {
  46     deepest = drops[0];
  47
  48     for (i = 1; i < drops.length; ++i)
  49       if (Element.isParent(drops[i].element, deepest.element))
  50         deepest = drops[i];
  51
  52     return deepest;
  53   },
  54
  55   isContained: function(element, drop) {
  56     var containmentNode;
  57     if(drop.tree) {
  58       containmentNode = element.treeNode;
  59     } else {
  60       containmentNode = element.parentNode;
  61     }
  62     return drop._containers.detect(function(c) { return containmentNode == c });
  63   },
  64
  65   isAffected: function(point, element, drop) {
  66     return (
  67       (drop.element!=element) &&
  68       ((!drop._containers) ||
  69         this.isContained(element, drop)) &&
  70       ((!drop.accept) ||
  71         (Element.classNames(element).detect(
  72           function(v) { return drop.accept.include(v) } ) )) &&
  73       Position.within(drop.element, point[0], point[1]) );
  74   },
  75
  76   deactivate: function(drop) {
  77     if(drop.hoverclass)
  78       Element.removeClassName(drop.element, drop.hoverclass);
  79     this.last_active = null;
  80   },
  81
  82   activate: function(drop) {
  83     if(drop.hoverclass)
  84       Element.addClassName(drop.element, drop.hoverclass);
  85     this.last_active = drop;
  86   },
  87
  88   show: function(point, element) {
  89     if(!this.drops.length) return;
  90     var drop, affected = [];
  91
  92     this.drops.each( function(drop) {
  93       if(Droppables.isAffected(point, element, drop))
  94         affected.push(drop);
  95     });
  96
  97     if(affected.length>0)
  98       drop = Droppables.findDeepestChild(affected);
  99
 100     if(this.last_active && this.last_active != drop) this.deactivate(this.last_active);
 101     if (drop) {
 102       Position.within(drop.element, point[0], point[1]);
 103       if(drop.onHover)
 104         drop.onHover(element, drop.element, Position.overlap(drop.overlap, drop.element));
 105
 106       if (drop != this.last_active) Droppables.activate(drop);
 107     }
 108   },
 109
 110   fire: function(event, element) {
 111     if(!this.last_active) return;
 112     Position.prepare();
 113
 114     if (this.isAffected([Event.pointerX(event), Event.pointerY(event)], element, this.last_active))
 115       if (this.last_active.onDrop) {
 116         this.last_active.onDrop(element, this.last_active.element, event);
 117         return true;
 118       }
 119   },
 120
 121   reset: function() {
 122     if(this.last_active)
 123       this.deactivate(this.last_active);
 124   }
 125 };
 126
 127 var Draggables = {
 128   drags: [],
 129   observers: [],
 130
 131   register: function(draggable) {
 132     if(this.drags.length == 0) {
 133       this.eventMouseUp   = this.endDrag.bindAsEventListener(this);
 134       this.eventMouseMove = this.updateDrag.bindAsEventListener(this);
 135       this.eventKeypress  = this.keyPress.bindAsEventListener(this);
 136
 137       Event.observe(document, "mouseup", this.eventMouseUp);
 138       Event.observe(document, "mousemove", this.eventMouseMove);
 139       Event.observe(document, "keypress", this.eventKeypress);
 140     }
 141     this.drags.push(draggable);
 142   },
 143
 144   unregister: function(draggable) {
 145     this.drags = this.drags.reject(function(d) { return d==draggable });
 146     if(this.drags.length == 0) {
 147       Event.stopObserving(document, "mouseup", this.eventMouseUp);
 148       Event.stopObserving(document, "mousemove", this.eventMouseMove);
 149       Event.stopObserving(document, "keypress", this.eventKeypress);
 150     }
 151   },
 152
 153   activate: function(draggable) {
 154     if(draggable.options.delay) {
 155       this._timeout = setTimeout(function() {
 156         Draggables._timeout = null;
 157         window.focus();
 158         Draggables.activeDraggable = draggable;
 159       }.bind(this), draggable.options.delay);
 160     } else {
 161       window.focus(); // allows keypress events if window isn't currently focused, fails for Safari
 162       this.activeDraggable = draggable;
 163     }
 164   },
 165
 166   deactivate: function() {
 167     this.activeDraggable = null;
 168   },
 169
 170   updateDrag: function(event) {
 171     if(!this.activeDraggable) return;
 172     var pointer = [Event.pointerX(event), Event.pointerY(event)];
 173     // Mozilla-based browsers fire successive mousemove events with
 174     // the same coordinates, prevent needless redrawing (moz bug?)
 175     if(this._lastPointer && (this._lastPointer.inspect() == pointer.inspect())) return;
 176     this._lastPointer = pointer;
 177
 178     this.activeDraggable.updateDrag(event, pointer);
 179   },
 180
 181   endDrag: function(event) {
 182     if(this._timeout) {
 183       clearTimeout(this._timeout);
 184       this._timeout = null;
 185     }
 186     if(!this.activeDraggable) return;
 187     this._lastPointer = null;
 188     this.activeDraggable.endDrag(event);
 189     this.activeDraggable = null;
 190   },
 191
 192   keyPress: function(event) {
 193     if(this.activeDraggable)
 194       this.activeDraggable.keyPress(event);
 195   },
 196
 197   addObserver: function(observer) {
 198     this.observers.push(observer);
 199     this._cacheObserverCallbacks();
 200   },
 201
 202   removeObserver: function(element) {  // element instead of observer fixes mem leaks
 203     this.observers = this.observers.reject( function(o) { return o.element==element });
 204     this._cacheObserverCallbacks();
 205   },
 206
 207   notify: function(eventName, draggable, event) {  // 'onStart', 'onEnd', 'onDrag'
 208     if(this[eventName+'Count'] > 0)
 209       this.observers.each( function(o) {
 210         if(o[eventName]) o[eventName](eventName, draggable, event);
 211       });
 212     if(draggable.options[eventName]) draggable.options[eventName](draggable, event);
 213   },
 214
 215   _cacheObserverCallbacks: function() {
 216     ['onStart','onEnd','onDrag'].each( function(eventName) {
 217       Draggables[eventName+'Count'] = Draggables.observers.select(
 218         function(o) { return o[eventName]; }
 219       ).length;
 220     });
 221   }
 222 };
 223
 224 /*--------------------------------------------------------------------------*/
 225
 226 var Draggable = Class.create({
 227   initialize: function(element) {
 228     var defaults = {
 229       handle: false,
 230       reverteffect: function(element, top_offset, left_offset) {
 231         var dur = Math.sqrt(Math.abs(top_offset^2)+Math.abs(left_offset^2))*0.02;
 232         new Effect.Move(element, { x: -left_offset, y: -top_offset, duration: dur,
 233           queue: {scope:'_draggable', position:'end'}
 234         });
 235       },
 236       endeffect: function(element) {
 237         var toOpacity = Object.isNumber(element._opacity) ? element._opacity : 1.0;
 238         new Effect.Opacity(element, {duration:0.2, from:0.7, to:toOpacity,
 239           queue: {scope:'_draggable', position:'end'},
 240           afterFinish: function(){
 241             Draggable._dragging[element] = false
 242           }
 243         });
 244       },
 245       zindex: 1000,
 246       revert: false,
 247       quiet: false,
 248       scroll: false,
 249       scrollSensitivity: 20,
 250       scrollSpeed: 15,
 251       snap: false,  // false, or xy or [x,y] or function(x,y){ return [x,y] }
 252       delay: 0
 253     };
 254
 255     if(!arguments[1] || Object.isUndefined(arguments[1].endeffect))
 256       Object.extend(defaults, {
 257         starteffect: function(element) {
 258           element._opacity = Element.getOpacity(element);
 259           Draggable._dragging[element] = true;
 260           new Effect.Opacity(element, {duration:0.2, from:element._opacity, to:0.7});
 261         }
 262       });
 263
 264     var options = Object.extend(defaults, arguments[1] || { });
 265
 266     this.element = $(element);
 267
 268     if(options.handle && Object.isString(options.handle))
 269       this.handle = this.element.down('.'+options.handle, 0);
 270
 271     if(!this.handle) this.handle = $(options.handle);
 272     if(!this.handle) this.handle = this.element;
 273
 274     if(options.scroll && !options.scroll.scrollTo && !options.scroll.outerHTML) {
 275       options.scroll = $(options.scroll);
 276       this._isScrollChild = Element.childOf(this.element, options.scroll);
 277     }
 278
 279     Element.makePositioned(this.element); // fix IE
 280
 281     this.options  = options;
 282     this.dragging = false;
 283
 284     this.eventMouseDown = this.initDrag.bindAsEventListener(this);
 285     Event.observe(this.handle, "mousedown", this.eventMouseDown);
 286
 287     Draggables.register(this);
 288   },
 289
 290   destroy: function() {
 291     Event.stopObserving(this.handle, "mousedown", this.eventMouseDown);
 292     Draggables.unregister(this);
 293   },
 294
 295   currentDelta: function() {
 296     return([
 297       parseInt(Element.getStyle(this.element,'left') || '0'),
 298       parseInt(Element.getStyle(this.element,'top') || '0')]);
 299   },
 300
 301   initDrag: function(event) {
 302     if(!Object.isUndefined(Draggable._dragging[this.element]) &&
 303       Draggable._dragging[this.element]) return;
 304     if(Event.isLeftClick(event)) {
 305       // abort on form elements, fixes a Firefox issue
 306       var src = Event.element(event);
 307       if((tag_name = src.tagName.toUpperCase()) && (
 308         tag_name=='INPUT' ||
 309         tag_name=='SELECT' ||
 310         tag_name=='OPTION' ||
 311         tag_name=='BUTTON' ||
 312         tag_name=='TEXTAREA')) return;
 313
 314       var pointer = [Event.pointerX(event), Event.pointerY(event)];
 315       var pos     = this.element.cumulativeOffset();
 316       this.offset = [0,1].map( function(i) { return (pointer[i] - pos[i]) });
 317
 318       Draggables.activate(this);
 319       Event.stop(event);
 320     }
 321   },
 322
 323   startDrag: function(event) {
 324     this.dragging = true;
 325     if(!this.delta)
 326       this.delta = this.currentDelta();
 327
 328     if(this.options.zindex) {
 329       this.originalZ = parseInt(Element.getStyle(this.element,'z-index') || 0);
 330       this.element.style.zIndex = this.options.zindex;
 331     }
 332
 333     if(this.options.ghosting) {
 334       this._clone = this.element.cloneNode(true);
 335       this._originallyAbsolute = (this.element.getStyle('position') == 'absolute');
 336       if (!this._originallyAbsolute)
 337         Position.absolutize(this.element);
 338       this.element.parentNode.insertBefore(this._clone, this.element);
 339     }
 340
 341     if(this.options.scroll) {
 342       if (this.options.scroll == window) {
 343         var where = this._getWindowScroll(this.options.scroll);
 344         this.originalScrollLeft = where.left;
 345         this.originalScrollTop = where.top;
 346       } else {
 347         this.originalScrollLeft = this.options.scroll.scrollLeft;
 348         this.originalScrollTop = this.options.scroll.scrollTop;
 349       }
 350     }
 351
 352     Draggables.notify('onStart', this, event);
 353
 354     if(this.options.starteffect) this.options.starteffect(this.element);
 355   },
 356
 357   updateDrag: function(event, pointer) {
 358     if(!this.dragging) this.startDrag(event);
 359
 360     if(!this.options.quiet){
 361       Position.prepare();
 362       Droppables.show(pointer, this.element);
 363     }
 364
 365     Draggables.notify('onDrag', this, event);
 366
 367     this.draw(pointer);
 368     if(this.options.change) this.options.change(this);
 369
 370     if(this.options.scroll) {
 371       this.stopScrolling();
 372
 373       var p;
 374       if (this.options.scroll == window) {
 375         with(this._getWindowScroll(this.options.scroll)) { p = [ left, top, left+width, top+height ]; }
 376       } else {
 377         p = Position.page(this.options.scroll).toArray();
 378         p[0] += this.options.scroll.scrollLeft + Position.deltaX;
 379         p[1] += this.options.scroll.scrollTop + Position.deltaY;
 380         p.push(p[0]+this.options.scroll.offsetWidth);
 381         p.push(p[1]+this.options.scroll.offsetHeight);
 382       }
 383       var speed = [0,0];
 384       if(pointer[0] < (p[0]+this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[0]+this.options.scrollSensitivity);
 385       if(pointer[1] < (p[1]+this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[1]+this.options.scrollSensitivity);
 386       if(pointer[0] > (p[2]-this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[2]-this.options.scrollSensitivity);
 387       if(pointer[1] > (p[3]-this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[3]-this.options.scrollSensitivity);
 388       this.startScrolling(speed);
 389     }
 390
 391     // fix AppleWebKit rendering
 392     if(Prototype.Browser.WebKit) window.scrollBy(0,0);
 393
 394     Event.stop(event);
 395   },
 396
 397   finishDrag: function(event, success) {
 398     this.dragging = false;
 399
 400     if(this.options.quiet){
 401       Position.prepare();
 402       var pointer = [Event.pointerX(event), Event.pointerY(event)];
 403       Droppables.show(pointer, this.element);
 404     }
 405
 406     if(this.options.ghosting) {
 407       if (!this._originallyAbsolute)
 408         Position.relativize(this.element);
 409       delete this._originallyAbsolute;
 410       Element.remove(this._clone);
 411       this._clone = null;
 412     }
 413
 414     var dropped = false;
 415     if(success) {
 416       dropped = Droppables.fire(event, this.element);
 417       if (!dropped) dropped = false;
 418     }
 419     if(dropped && this.options.onDropped) this.options.onDropped(this.element);
 420     Draggables.notify('onEnd', this, event);
 421
 422     var revert = this.options.revert;
 423     if(revert && Object.isFunction(revert)) revert = revert(this.element);
 424
 425     var d = this.currentDelta();
 426     if(revert && this.options.reverteffect) {
 427       if (dropped == 0 || revert != 'failure')
 428         this.options.reverteffect(this.element,
 429           d[1]-this.delta[1], d[0]-this.delta[0]);
 430     } else {
 431       this.delta = d;
 432     }
 433
 434     if(this.options.zindex)
 435       this.element.style.zIndex = this.originalZ;
 436
 437     if(this.options.endeffect)
 438       this.options.endeffect(this.element);
 439
 440     Draggables.deactivate(this);
 441     Droppables.reset();
 442   },
 443
 444   keyPress: function(event) {
 445     if(event.keyCode!=Event.KEY_ESC) return;
 446     this.finishDrag(event, false);
 447     Event.stop(event);
 448   },
 449
 450   endDrag: function(event) {
 451     if(!this.dragging) return;
 452     this.stopScrolling();
 453     this.finishDrag(event, true);
 454     Event.stop(event);
 455   },
 456
 457   draw: function(point) {
 458     var pos = this.element.cumulativeOffset();
 459     if(this.options.ghosting) {
 460       var r   = Position.realOffset(this.element);
 461       pos[0] += r[0] - Position.deltaX; pos[1] += r[1] - Position.deltaY;
 462     }
 463
 464     var d = this.currentDelta();
 465     pos[0] -= d[0]; pos[1] -= d[1];
 466
 467     if(this.options.scroll && (this.options.scroll != window && this._isScrollChild)) {
 468       pos[0] -= this.options.scroll.scrollLeft-this.originalScrollLeft;
 469       pos[1] -= this.options.scroll.scrollTop-this.originalScrollTop;
 470     }
 471
 472     var p = [0,1].map(function(i){
 473       return (point[i]-pos[i]-this.offset[i])
 474     }.bind(this));
 475
 476     if(this.options.snap) {
 477       if(Object.isFunction(this.options.snap)) {
 478         p = this.options.snap(p[0],p[1],this);
 479       } else {
 480       if(Object.isArray(this.options.snap)) {
 481         p = p.map( function(v, i) {
 482           return (v/this.options.snap[i]).round()*this.options.snap[i] }.bind(this));
 483       } else {
 484         p = p.map( function(v) {
 485           return (v/this.options.snap).round()*this.options.snap }.bind(this));
 486       }
 487     }}
 488
 489     var style = this.element.style;
 490     if((!this.options.constraint) || (this.options.constraint=='horizontal'))
 491       style.left = p[0] + "px";
 492     if((!this.options.constraint) || (this.options.constraint=='vertical'))
 493       style.top  = p[1] + "px";
 494
 495     if(style.visibility=="hidden") style.visibility = ""; // fix gecko rendering
 496   },
 497
 498   stopScrolling: function() {
 499     if(this.scrollInterval) {
 500       clearInterval(this.scrollInterval);
 501       this.scrollInterval = null;
 502       Draggables._lastScrollPointer = null;
 503     }
 504   },
 505
 506   startScrolling: function(speed) {
 507     if(!(speed[0] || speed[1])) return;
 508     this.scrollSpeed = [speed[0]*this.options.scrollSpeed,speed[1]*this.options.scrollSpeed];
 509     this.lastScrolled = new Date();
 510     this.scrollInterval = setInterval(this.scroll.bind(this), 10);
 511   },
 512
 513   scroll: function() {
 514     var current = new Date();
 515     var delta = current - this.lastScrolled;
 516     this.lastScrolled = current;
 517     if(this.options.scroll == window) {
 518       with (this._getWindowScroll(this.options.scroll)) {
 519         if (this.scrollSpeed[0] || this.scrollSpeed[1]) {
 520           var d = delta / 1000;
 521           this.options.scroll.scrollTo( left + d*this.scrollSpeed[0], top + d*this.scrollSpeed[1] );
 522         }
 523       }
 524     } else {
 525       this.options.scroll.scrollLeft += this.scrollSpeed[0] * delta / 1000;
 526       this.options.scroll.scrollTop  += this.scrollSpeed[1] * delta / 1000;
 527     }
 528
 529     Position.prepare();
 530     Droppables.show(Draggables._lastPointer, this.element);
 531     Draggables.notify('onDrag', this);
 532     if (this._isScrollChild) {
 533       Draggables._lastScrollPointer = Draggables._lastScrollPointer || $A(Draggables._lastPointer);
 534       Draggables._lastScrollPointer[0] += this.scrollSpeed[0] * delta / 1000;
 535       Draggables._lastScrollPointer[1] += this.scrollSpeed[1] * delta / 1000;
 536       if (Draggables._lastScrollPointer[0] < 0)
 537         Draggables._lastScrollPointer[0] = 0;
 538       if (Draggables._lastScrollPointer[1] < 0)
 539         Draggables._lastScrollPointer[1] = 0;
 540       this.draw(Draggables._lastScrollPointer);
 541     }
 542
 543     if(this.options.change) this.options.change(this);
 544   },
 545
 546   _getWindowScroll: function(w) {
 547     var T, L, W, H;
 548     with (w.document) {
 549       if (w.document.documentElement && documentElement.scrollTop) {
 550         T = documentElement.scrollTop;
 551         L = documentElement.scrollLeft;
 552       } else if (w.document.body) {
 553         T = body.scrollTop;
 554         L = body.scrollLeft;
 555       }
 556       if (w.innerWidth) {
 557         W = w.innerWidth;
 558         H = w.innerHeight;
 559       } else if (w.document.documentElement && documentElement.clientWidth) {
 560         W = documentElement.clientWidth;
 561         H = documentElement.clientHeight;
 562       } else {
 563         W = body.offsetWidth;
 564         H = body.offsetHeight;
 565       }
 566     }
 567     return { top: T, left: L, width: W, height: H };
 568   }
 569 });
 570
 571 Draggable._dragging = { };
 572
 573 /*--------------------------------------------------------------------------*/
 574
 575 var SortableObserver = Class.create({
 576   initialize: function(element, observer) {
 577     this.element   = $(element);
 578     this.observer  = observer;
 579     this.lastValue = Sortable.serialize(this.element);
 580   },
 581
 582   onStart: function() {
 583     this.lastValue = Sortable.serialize(this.element);
 584   },
 585
 586   onEnd: function() {
 587     Sortable.unmark();
 588     if(this.lastValue != Sortable.serialize(this.element))
 589       this.observer(this.element)
 590   }
 591 });
 592
 593 var Sortable = {
 594   SERIALIZE_RULE: /^[^_\-](?:[A-Za-z0-9\-\_]*)[_](.*)$/,
 595
 596   sortables: { },
 597
 598   _findRootElement: function(element) {
 599     while (element.tagName.toUpperCase() != "BODY") {
 600       if(element.id && Sortable.sortables[element.id]) return element;
 601       element = element.parentNode;
 602     }
 603   },
 604
 605   options: function(element) {
 606     element = Sortable._findRootElement($(element));
 607     if(!element) return;
 608     return Sortable.sortables[element.id];
 609   },
 610
 611   destroy: function(element){
 612     element = $(element);
 613     var s = Sortable.sortables[element.id];
 614
 615     if(s) {
 616       Draggables.removeObserver(s.element);
 617       s.droppables.each(function(d){ Droppables.remove(d) });
 618       s.draggables.invoke('destroy');
 619
 620       delete Sortable.sortables[s.element.id];
 621     }
 622   },
 623
 624   create: function(element) {
 625     element = $(element);
 626     var options = Object.extend({
 627       element:     element,
 628       tag:         'li',       // assumes li children, override with tag: 'tagname'
 629       dropOnEmpty: false,
 630       tree:        false,
 631       treeTag:     'ul',
 632       overlap:     'vertical', // one of 'vertical', 'horizontal'
 633       constraint:  'vertical', // one of 'vertical', 'horizontal', false
 634       containment: element,    // also takes array of elements (or id's); or false
 635       handle:      false,      // or a CSS class
 636       only:        false,
 637       delay:       0,
 638       hoverclass:  null,
 639       ghosting:    false,
 640       quiet:       false,
 641       scroll:      false,
 642       scrollSensitivity: 20,
 643       scrollSpeed: 15,
 644       format:      this.SERIALIZE_RULE,
 645
 646       // these take arrays of elements or ids and can be
 647       // used for better initialization performance
 648       elements:    false,
 649       handles:     false,
 650
 651       onChange:    Prototype.emptyFunction,
 652       onUpdate:    Prototype.emptyFunction
 653     }, arguments[1] || { });
 654
 655     // clear any old sortable with same element
 656     this.destroy(element);
 657
 658     // build options for the draggables
 659     var options_for_draggable = {
 660       revert:      true,
 661       quiet:       options.quiet,
 662       scroll:      options.scroll,
 663       scrollSpeed: options.scrollSpeed,
 664       scrollSensitivity: options.scrollSensitivity,
 665       delay:       options.delay,
 666       ghosting:    options.ghosting,
 667       constraint:  options.constraint,
 668       handle:      options.handle };
 669
 670     if(options.starteffect)
 671       options_for_draggable.starteffect = options.starteffect;
 672
 673     if(options.reverteffect)
 674       options_for_draggable.reverteffect = options.reverteffect;
 675     else
 676       if(options.ghosting) options_for_draggable.reverteffect = function(element) {
 677         element.style.top  = 0;
 678         element.style.left = 0;
 679       };
 680
 681     if(options.endeffect)
 682       options_for_draggable.endeffect = options.endeffect;
 683
 684     if(options.zindex)
 685       options_for_draggable.zindex = options.zindex;
 686
 687     // build options for the droppables
 688     var options_for_droppable = {
 689       overlap:     options.overlap,
 690       containment: options.containment,
 691       tree:        options.tree,
 692       hoverclass:  options.hoverclass,
 693       onHover:     Sortable.onHover
 694     };
 695
 696     var options_for_tree = {
 697       onHover:      Sortable.onEmptyHover,
 698       overlap:      options.overlap,
 699       containment:  options.containment,
 700       hoverclass:   options.hoverclass
 701     };
 702
 703     // fix for gecko engine
 704     Element.cleanWhitespace(element);
 705
 706     options.draggables = [];
 707     options.droppables = [];
 708
 709     // drop on empty handling
 710     if(options.dropOnEmpty || options.tree) {
 711       Droppables.add(element, options_for_tree);
 712       options.droppables.push(element);
 713     }
 714
 715     (options.elements || this.findElements(element, options) || []).each( function(e,i) {
 716       var handle = options.handles ? $(options.handles[i]) :
 717         (options.handle ? $(e).select('.' + options.handle)[0] : e);
 718       options.draggables.push(
 719         new Draggable(e, Object.extend(options_for_draggable, { handle: handle })));
 720       Droppables.add(e, options_for_droppable);
 721       if(options.tree) e.treeNode = element;
 722       options.droppables.push(e);
 723     });
 724
 725     if(options.tree) {
 726       (Sortable.findTreeElements(element, options) || []).each( function(e) {
 727         Droppables.add(e, options_for_tree);
 728         e.treeNode = element;
 729         options.droppables.push(e);
 730       });
 731     }
 732
 733     // keep reference
 734     this.sortables[element.identify()] = options;
 735
 736     // for onupdate
 737     Draggables.addObserver(new SortableObserver(element, options.onUpdate));
 738
 739   },
 740
 741   // return all suitable-for-sortable elements in a guaranteed order
 742   findElements: function(element, options) {
 743     return Element.findChildren(
 744       element, options.only, options.tree ? true : false, options.tag);
 745   },
 746
 747   findTreeElements: function(element, options) {
 748     return Element.findChildren(
 749       element, options.only, options.tree ? true : false, options.treeTag);
 750   },
 751
 752   onHover: function(element, dropon, overlap) {
 753     if(Element.isParent(dropon, element)) return;
 754
 755     if(overlap > .33 && overlap < .66 && Sortable.options(dropon).tree) {
 756       return;
 757     } else if(overlap>0.5) {
 758       Sortable.mark(dropon, 'before');
 759       if(dropon.previousSibling != element) {
 760         var oldParentNode = element.parentNode;
 761         element.style.visibility = "hidden"; // fix gecko rendering
 762         dropon.parentNode.insertBefore(element, dropon);
 763         if(dropon.parentNode!=oldParentNode)
 764           Sortable.options(oldParentNode).onChange(element);
 765         Sortable.options(dropon.parentNode).onChange(element);
 766       }
 767     } else {
 768       Sortable.mark(dropon, 'after');
 769       var nextElement = dropon.nextSibling || null;
 770       if(nextElement != element) {
 771         var oldParentNode = element.parentNode;
 772         element.style.visibility = "hidden"; // fix gecko rendering
 773         dropon.parentNode.insertBefore(element, nextElement);
 774         if(dropon.parentNode!=oldParentNode)
 775           Sortable.options(oldParentNode).onChange(element);
 776         Sortable.options(dropon.parentNode).onChange(element);
 777       }
 778     }
 779   },
 780
 781   onEmptyHover: function(element, dropon, overlap) {
 782     var oldParentNode = element.parentNode;
 783     var droponOptions = Sortable.options(dropon);
 784
 785     if(!Element.isParent(dropon, element)) {
 786       var index;
 787
 788       var children = Sortable.findElements(dropon, {tag: droponOptions.tag, only: droponOptions.only});
 789       var child = null;
 790
 791       if(children) {
 792         var offset = Element.offsetSize(dropon, droponOptions.overlap) * (1.0 - overlap);
 793
 794         for (index = 0; index < children.length; index += 1) {
 795           if (offset - Element.offsetSize (children[index], droponOptions.overlap) >= 0) {
 796             offset -= Element.offsetSize (children[index], droponOptions.overlap);
 797           } else if (offset - (Element.offsetSize (children[index], droponOptions.overlap) / 2) >= 0) {
 798             child = index + 1 < children.length ? children[index + 1] : null;
 799             break;
 800           } else {
 801             child = children[index];
 802             break;
 803           }
 804         }
 805       }
 806
 807       dropon.insertBefore(element, child);
 808
 809       Sortable.options(oldParentNode).onChange(element);
 810       droponOptions.onChange(element);
 811     }
 812   },
 813
 814   unmark: function() {
 815     if(Sortable._marker) Sortable._marker.hide();
 816   },
 817
 818   mark: function(dropon, position) {
 819     // mark on ghosting only
 820     var sortable = Sortable.options(dropon.parentNode);
 821     if(sortable && !sortable.ghosting) return;
 822
 823     if(!Sortable._marker) {
 824       Sortable._marker =
 825         ($('dropmarker') || Element.extend(document.createElement('DIV'))).
 826           hide().addClassName('dropmarker').setStyle({position:'absolute'});
 827       document.getElementsByTagName("body").item(0).appendChild(Sortable._marker);
 828     }
 829     var offsets = dropon.cumulativeOffset();
 830     Sortable._marker.setStyle({left: offsets[0]+'px', top: offsets[1] + 'px'});
 831
 832     if(position=='after')
 833       if(sortable.overlap == 'horizontal')
 834         Sortable._marker.setStyle({left: (offsets[0]+dropon.clientWidth) + 'px'});
 835       else
 836         Sortable._marker.setStyle({top: (offsets[1]+dropon.clientHeight) + 'px'});
 837
 838     Sortable._marker.show();
 839   },
 840
 841   _tree: function(element, options, parent) {
 842     var children = Sortable.findElements(element, options) || [];
 843
 844     for (var i = 0; i < children.length; ++i) {
 845       var match = children[i].id.match(options.format);
 846
 847       if (!match) continue;
 848
 849       var child = {
 850         id: encodeURIComponent(match ? match[1] : null),
 851         element: element,
 852         parent: parent,
 853         children: [],
 854         position: parent.children.length,
 855         container: $(children[i]).down(options.treeTag)
 856       };
 857
 858       /* Get the element containing the children and recurse over it */
 859       if (child.container)
 860         this._tree(child.container, options, child);
 861
 862       parent.children.push (child);
 863     }
 864
 865     return parent;
 866   },
 867
 868   tree: function(element) {
 869     element = $(element);
 870     var sortableOptions = this.options(element);
 871     var options = Object.extend({
 872       tag: sortableOptions.tag,
 873       treeTag: sortableOptions.treeTag,
 874       only: sortableOptions.only,
 875       name: element.id,
 876       format: sortableOptions.format
 877     }, arguments[1] || { });
 878
 879     var root = {
 880       id: null,
 881       parent: null,
 882       children: [],
 883       container: element,
 884       position: 0
 885     };
 886
 887     return Sortable._tree(element, options, root);
 888   },
 889
 890   /* Construct a [i] index for a particular node */
 891   _constructIndex: function(node) {
 892     var index = '';
 893     do {
 894       if (node.id) index = '[' + node.position + ']' + index;
 895     } while ((node = node.parent) != null);
 896     return index;
 897   },
 898
 899   sequence: function(element) {
 900     element = $(element);
 901     var options = Object.extend(this.options(element), arguments[1] || { });
 902
 903     return $(this.findElements(element, options) || []).map( function(item) {
 904       return item.id.match(options.format) ? item.id.match(options.format)[1] : '';
 905     });
 906   },
 907
 908   setSequence: function(element, new_sequence) {
 909     element = $(element);
 910     var options = Object.extend(this.options(element), arguments[2] || { });
 911
 912     var nodeMap = { };
 913     this.findElements(element, options).each( function(n) {
 914         if (n.id.match(options.format))
 915             nodeMap[n.id.match(options.format)[1]] = [n, n.parentNode];
 916         n.parentNode.removeChild(n);
 917     });
 918
 919     new_sequence.each(function(ident) {
 920       var n = nodeMap[ident];
 921       if (n) {
 922         n[1].appendChild(n[0]);
 923         delete nodeMap[ident];
 924       }
 925     });
 926   },
 927
 928   serialize: function(element) {
 929     element = $(element);
 930     var options = Object.extend(Sortable.options(element), arguments[1] || { });
 931     var name = encodeURIComponent(
 932       (arguments[1] && arguments[1].name) ? arguments[1].name : element.id);
 933
 934     if (options.tree) {
 935       return Sortable.tree(element, arguments[1]).children.map( function (item) {
 936         return [name + Sortable._constructIndex(item) + "[id]=" +
 937                 encodeURIComponent(item.id)].concat(item.children.map(arguments.callee));
 938       }).flatten().join('&');
 939     } else {
 940       return Sortable.sequence(element, arguments[1]).map( function(item) {
 941         return name + "[]=" + encodeURIComponent(item);
 942       }).join('&');
 943     }
 944   }
 945 };
 946
 947 // Returns true if child is contained within element
 948 Element.isParent = function(child, element) {
 949   if (!child.parentNode || child == element) return false;
 950   if (child.parentNode == element) return true;
 951   return Element.isParent(child.parentNode, element);
 952 };
 953
 954 Element.findChildren = function(element, only, recursive, tagName) {
 955   if(!element.hasChildNodes()) return null;
 956   tagName = tagName.toUpperCase();
 957   if(only) only = [only].flatten();
 958   var elements = [];
 959   $A(element.childNodes).each( function(e) {
 960     if(e.tagName && e.tagName.toUpperCase()==tagName &&
 961       (!only || (Element.classNames(e).detect(function(v) { return only.include(v) }))))
 962         elements.push(e);
 963     if(recursive) {
 964       var grandchildren = Element.findChildren(e, only, recursive, tagName);
 965       if(grandchildren) elements.push(grandchildren);
 966     }
 967   });
 968
 969   return (elements.length>0 ? elements.flatten() : []);
 970 };
 971
 972 Element.offsetSize = function (element, type) {
 973   return element['offset' + ((type=='vertical' || type=='height') ? 'Height' : 'Width')];
 974 };