public/javascripts/dragdrop.js

   1 // Copyright (c) 2005-2008 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 if(Object.isUndefined(Effect))
   8   throw("dragdrop.js requires including script.aculo.us' effects.js library");
   9
  10 var Droppables = {
  11   drops: [],
  12
  13   remove: function(element) {
  14     this.drops = this.drops.reject(function(d) { return d.element==$(element) });
  15   },
  16
  17   add: function(element) {
  18     element = $(element);
  19     var options = Object.extend({
  20       greedy:     true,
  21       hoverclass: null,
  22       tree:       false
  23     }, arguments[1] || { });
  24
  25     // cache containers
  26     if(options.containment) {
  27       options._containers = [];
  28       var containment = options.containment;
  29       if(Object.isArray(containment)) {
  30         containment.each( function(c) { options._containers.push($(c)) });
  31       } else {
  32         options._containers.push($(containment));
  33       }
  34     }
  35
  36     if(options.accept) options.accept = [options.accept].flatten();
  37
  38     Element.makePositioned(element); // fix IE
  39     options.element = element;
  40
  41     this.drops.push(options);
  42   },
  43
  44   findDeepestChild: function(drops) {
  45     deepest = drops[0];
  46
  47     for (i = 1; i < drops.length; ++i)
  48       if (Element.isParent(drops[i].element, deepest.element))
  49         deepest = drops[i];
  50
  51     return deepest;
  52   },
  53
  54   isContained: function(element, drop) {
  55     var containmentNode;
  56     if(drop.tree) {
  57       containmentNode = element.treeNode;
  58     } else {
  59       containmentNode = element.parentNode;
  60     }
  61     return drop._containers.detect(function(c) { return containmentNode == c });
  62   },
  63
  64   isAffected: function(point, element, drop) {
  65     return (
  66       (drop.element!=element) &&
  67       ((!drop._containers) ||
  68         this.isContained(element, drop)) &&
  69       ((!drop.accept) ||
  70         (Element.classNames(element).detect(
  71           function(v) { return drop.accept.include(v) } ) )) &&
  72       Position.within(drop.element, point[0], point[1]) );
  73   },
  74
  75   deactivate: function(drop) {
  76     if(drop.hoverclass)
  77       Element.removeClassName(drop.element, drop.hoverclass);
  78     this.last_active = null;
  79   },
  80
  81   activate: function(drop) {
  82     if(drop.hoverclass)
  83       Element.addClassName(drop.element, drop.hoverclass);
  84     this.last_active = drop;
  85   },
  86
  87   show: function(point, element) {
  88     if(!this.drops.length) return;
  89     var drop, affected = [];
  90
  91     this.drops.each( function(drop) {
  92       if(Droppables.isAffected(point, element, drop))
  93         affected.push(drop);
  94     });
  95
  96     if(affected.length>0)
  97       drop = Droppables.findDeepestChild(affected);
  98
  99     if(this.last_active && this.last_active != drop) this.deactivate(this.last_active);
 100     if (drop) {
 101       Position.within(drop.element, point[0], point[1]);
 102       if(drop.onHover)
 103         drop.onHover(element, drop.element, Position.overlap(drop.overlap, drop.element));
 104
 105       if (drop != this.last_active) Droppables.activate(drop);
 106     }
 107   },
 108
 109   fire: function(event, element) {
 110     if(!this.last_active) return;
 111     Position.prepare();
 112
 113     if (this.isAffected([Event.pointerX(event), Event.pointerY(event)], element, this.last_active))
 114       if (this.last_active.onDrop) {
 115         this.last_active.onDrop(element, this.last_active.element, event);
 116         return true;
 117       }
 118   },
 119
 120   reset: function() {
 121     if(this.last_active)
 122       this.deactivate(this.last_active);
 123   }
 124 }
 125
 126 var Draggables = {
 127   drags: [],
 128   observers: [],
 129
 130   register: function(draggable) {
 131     if(this.drags.length == 0) {
 132       this.eventMouseUp   = this.endDrag.bindAsEventListener(this);
 133       this.eventMouseMove = this.updateDrag.bindAsEventListener(this);
 134       this.eventKeypress  = this.keyPress.bindAsEventListener(this);
 135
 136       Event.observe(document, "mouseup", this.eventMouseUp);
 137       Event.observe(document, "mousemove", this.eventMouseMove);
 138       Event.observe(document, "keypress", this.eventKeypress);
 139     }
 140     this.drags.push(draggable);
 141   },
 142
 143   unregister: function(draggable) {
 144     this.drags = this.drags.reject(function(d) { return d==draggable });
 145     if(this.drags.length == 0) {
 146       Event.stopObserving(document, "mouseup", this.eventMouseUp);
 147       Event.stopObserving(document, "mousemove", this.eventMouseMove);
 148       Event.stopObserving(document, "keypress", this.eventKeypress);
 149     }
 150   },
 151
 152   activate: function(draggable) {
 153     if(draggable.options.delay) {
 154       this._timeout = setTimeout(function() {
 155         Draggables._timeout = null;
 156         window.focus();
 157         Draggables.activeDraggable = draggable;
 158       }.bind(this), draggable.options.delay);
 159     } else {
 160       window.focus(); // allows keypress events if window isn't currently focused, fails for Safari
 161       this.activeDraggable = draggable;
 162     }
 163   },
 164
 165   deactivate: function() {
 166     this.activeDraggable = null;
 167   },
 168
 169   updateDrag: function(event) {
 170     if(!this.activeDraggable) return;
 171     var pointer = [Event.pointerX(event), Event.pointerY(event)];
 172     // Mozilla-based browsers fire successive mousemove events with
 173     // the same coordinates, prevent needless redrawing (moz bug?)
 174     if(this._lastPointer && (this._lastPointer.inspect() == pointer.inspect())) return;
 175     this._lastPointer = pointer;
 176
 177     this.activeDraggable.updateDrag(event, pointer);
 178   },
 179
 180   endDrag: function(event) {
 181     if(this._timeout) {
 182       clearTimeout(this._timeout);
 183       this._timeout = null;
 184     }
 185     if(!this.activeDraggable) return;
 186     this._lastPointer = null;
 187     this.activeDraggable.endDrag(event);
 188     this.activeDraggable = null;
 189   },
 190
 191   keyPress: function(event) {
 192     if(this.activeDraggable)
 193       this.activeDraggable.keyPress(event);
 194   },
 195
 196   addObserver: function(observer) {
 197     this.observers.push(observer);
 198     this._cacheObserverCallbacks();
 199   },
 200
 201   removeObserver: function(element) {  // element instead of observer fixes mem leaks
 202     this.observers = this.observers.reject( function(o) { return o.element==element });
 203     this._cacheObserverCallbacks();
 204   },
 205
 206   notify: function(eventName, draggable, event) {  // 'onStart', 'onEnd', 'onDrag'
 207     if(this[eventName+'Count'] > 0)
 208       this.observers.each( function(o) {
 209         if(o[eventName]) o[eventName](eventName, draggable, event);
 210       });
 211     if(draggable.options[eventName]) draggable.options[eventName](draggable, event);
 212   },
 213
 214   _cacheObserverCallbacks: function() {
 215     ['onStart','onEnd','onDrag'].each( function(eventName) {
 216       Draggables[eventName+'Count'] = Draggables.observers.select(
 217         function(o) { return o[eventName]; }
 218       ).length;
 219     });
 220   }
 221 }
 222
 223 /*--------------------------------------------------------------------------*/
 224
 225 var Draggable = Class.create({
 226   initialize: function(element) {
 227     var defaults = {
 228       handle: false,
 229       reverteffect: function(element, top_offset, left_offset) {
 230         var dur = Math.sqrt(Math.abs(top_offset^2)+Math.abs(left_offset^2))*0.02;
 231         new Effect.Move(element, { x: -left_offset, y: -top_offset, duration: dur,
 232           queue: {scope:'_draggable', position:'end'}
 233         });
 234       },
 235       endeffect: function(element) {
 236         var toOpacity = Object.isNumber(element._opacity) ? element._opacity : 1.0;
 237         new Effect.Opacity(element, {duration:0.2, from:0.7, to:toOpacity,
 238           queue: {scope:'_draggable', position:'end'},
 239           afterFinish: function(){
 240             Draggable._dragging[element] = false
 241           }
 242         });
 243       },
 244       zindex: 1000,
 245       revert: false,
 246       quiet: false,
 247       scroll: false,
 248       scrollSensitivity: 20,
 249       scrollSpeed: 15,
 250       snap: false,  // false, or xy or [x,y] or function(x,y){ return [x,y] }
 251       delay: 0
 252     };
 253
 254     if(!arguments[1] || Object.isUndefined(arguments[1].endeffect))
 255       Object.extend(defaults, {
 256         starteffect: function(element) {
 257           element._opacity = Element.getOpacity(element);
 258           Draggable._dragging[element] = true;
 259           new Effect.Opacity(element, {duration:0.2, from:element._opacity, to:0.7});
 260         }
 261       });
 262
 263     var options = Object.extend(defaults, arguments[1] || { });
 264
 265     this.element = $(element);
 266
 267     if(options.handle && Object.isString(options.handle))
 268       this.handle = this.element.down('.'+options.handle, 0);
 269
 270     if(!this.handle) this.handle = $(options.handle);
 271     if(!this.handle) this.handle = this.element;
 272
 273     if(options.scroll && !options.scroll.scrollTo && !options.scroll.outerHTML) {
 274       options.scroll = $(options.scroll);
 275       this._isScrollChild = Element.childOf(this.element, options.scroll);
 276     }
 277
 278     Element.makePositioned(this.element); // fix IE
 279
 280     this.options  = options;
 281     this.dragging = false;
 282
 283     this.eventMouseDown = this.initDrag.bindAsEventListener(this);
 284     Event.observe(this.handle, "mousedown", this.eventMouseDown);
 285
 286     Draggables.register(this);
 287   },
 288
 289   destroy: function() {
 290     Event.stopObserving(this.handle, "mousedown", this.eventMouseDown);
 291     Draggables.unregister(this);
 292   },
 293
 294   currentDelta: function() {
 295     return([
 296       parseInt(Element.getStyle(this.element,'left') || '0'),
 297       parseInt(Element.getStyle(this.element,'top') || '0')]);
 298   },
 299
 300   initDrag: function(event) {
 301     if(!Object.isUndefined(Draggable._dragging[this.element]) &&
 302       Draggable._dragging[this.element]) return;
 303     if(Event.isLeftClick(event)) {
 304       // abort on form elements, fixes a Firefox issue
 305       var src = Event.element(event);
 306       if((tag_name = src.tagName.toUpperCase()) && (
 307         tag_name=='INPUT' ||
 308         tag_name=='SELECT' ||
 309         tag_name=='OPTION' ||
 310         tag_name=='BUTTON' ||
 311         tag_name=='TEXTAREA')) return;
 312
 313       var pointer = [Event.pointerX(event), Event.pointerY(event)];
 314       var pos     = Position.cumulativeOffset(this.element);
 315       this.offset = [0,1].map( function(i) { return (pointer[i] - pos[i]) });
 316
 317       Draggables.activate(this);
 318       Event.stop(event);
 319     }
 320   },
 321
 322   startDrag: function(event) {
 323     this.dragging = true;
 324     if(!this.delta)
 325       this.delta = this.currentDelta();
 326
 327     if(this.options.zindex) {
 328       this.originalZ = parseInt(Element.getStyle(this.element,'z-index') || 0);
 329       this.element.style.zIndex = this.options.zindex;
 330     }
 331
 332     if(this.options.ghosting) {
 333       this._clone = this.element.cloneNode(true);
 334       this.element._originallyAbsolute = (this.element.getStyle('position') == 'absolute');
 335       if (!this.element._originallyAbsolute)
 336         Position.absolutize(this.element);
 337       this.element.parentNode.insertBefore(this._clone, this.element);
 338     }
 339
 340     if(this.options.scroll) {
 341       if (this.options.scroll == window) {
 342         var where = this._getWindowScroll(this.options.scroll);
 343         this.originalScrollLeft = where.left;
 344         this.originalScrollTop = where.top;
 345       } else {
 346         this.originalScrollLeft = this.options.scroll.scrollLeft;
 347         this.originalScrollTop = this.options.scroll.scrollTop;
 348       }
 349     }
 350
 351     Draggables.notify('onStart', this, event);
 352
 353     if(this.options.starteffect) this.options.starteffect(this.element);
 354   },
 355
 356   updateDrag: function(event, pointer) {
 357     if(!this.dragging) this.startDrag(event);
 358
 359     if(!this.options.quiet){
 360       Position.prepare();
 361       Droppables.show(pointer, this.element);
 362     }
 363
 364     Draggables.notify('onDrag', this, event);
 365
 366     this.draw(pointer);
 367     if(this.options.change) this.options.change(this);
 368
 369     if(this.options.scroll) {
 370       this.stopScrolling();
 371
 372       var p;
 373       if (this.options.scroll == window) {
 374         with(this._getWindowScroll(this.options.scroll)) { p = [ left, top, left+width, top+height ]; }
 375       } else {
 376         p = Position.page(this.options.scroll);
 377         p[0] += this.options.scroll.scrollLeft + Position.deltaX;
 378         p[1] += this.options.scroll.scrollTop + Position.deltaY;
 379         p.push(p[0]+this.options.scroll.offsetWidth);
 380         p.push(p[1]+this.options.scroll.offsetHeight);
 381       }
 382       var speed = [0,0];
 383       if(pointer[0] < (p[0]+this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[0]+this.options.scrollSensitivity);
 384       if(pointer[1] < (p[1]+this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[1]+this.options.scrollSensitivity);
 385       if(pointer[0] > (p[2]-this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[2]-this.options.scrollSensitivity);
 386       if(pointer[1] > (p[3]-this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[3]-this.options.scrollSensitivity);
 387       this.startScrolling(speed);
 388     }
 389
 390     // fix AppleWebKit rendering
 391     if(Prototype.Browser.WebKit) window.scrollBy(0,0);
 392
 393     Event.stop(event);
 394   },
 395
 396   finishDrag: function(event, success) {
 397     this.dragging = false;
 398
 399     if(this.options.quiet){
 400       Position.prepare();
 401       var pointer = [Event.pointerX(event), Event.pointerY(event)];
 402       Droppables.show(pointer, this.element);
 403     }
 404
 405     if(this.options.ghosting) {
 406       if (!this.element._originallyAbsolute)
 407         Position.relativize(this.element);
 408       delete this.element._originallyAbsolute;
 409       Element.remove(this._clone);
 410       this._clone = null;
 411     }
 412
 413     var dropped = false;
 414     if(success) {
 415       dropped = Droppables.fire(event, this.element);
 416       if (!dropped) dropped = false;
 417     }
 418     if(dropped && this.options.onDropped) this.options.onDropped(this.element);
 419     Draggables.notify('onEnd', this, event);
 420
 421     var revert = this.options.revert;
 422     if(revert && Object.isFunction(revert)) revert = revert(this.element);
 423
 424     var d = this.currentDelta();
 425     if(revert && this.options.reverteffect) {
 426       if (dropped == 0 || revert != 'failure')
 427         this.options.reverteffect(this.element,
 428           d[1]-this.delta[1], d[0]-this.delta[0]);
 429     } else {
 430       this.delta = d;
 431     }
 432
 433     if(this.options.zindex)
 434       this.element.style.zIndex = this.originalZ;
 435
 436     if(this.options.endeffect)
 437       this.options.endeffect(this.element);
 438
 439     Draggables.deactivate(this);
 440     Droppables.reset();
 441   },
 442
 443   keyPress: function(event) {
 444     if(event.keyCode!=Event.KEY_ESC) return;
 445     this.finishDrag(event, false);
 446     Event.stop(event);
 447   },
 448
 449   endDrag: function(event) {
 450     if(!this.dragging) return;
 451     this.stopScrolling();
 452     this.finishDrag(event, true);
 453     Event.stop(event);
 454   },
 455
 456   draw: function(point) {
 457     var pos = Position.cumulativeOffset(this.element);
 458     if(this.options.ghosting) {
 459       var r   = Position.realOffset(this.element);
 460       pos[0] += r[0] - Position.deltaX; pos[1] += r[1] - Position.deltaY;
 461     }
 462
 463     var d = this.currentDelta();
 464     pos[0] -= d[0]; pos[1] -= d[1];
 465
 466     if(this.options.scroll && (this.options.scroll != window && this._isScrollChild)) {
 467       pos[0] -= this.options.scroll.scrollLeft-this.originalScrollLeft;
 468       pos[1] -= this.options.scroll.scrollTop-this.originalScrollTop;
 469     }
 470
 471     var p = [0,1].map(function(i){
 472       return (point[i]-pos[i]-this.offset[i])
 473     }.bind(this));
 474
 475     if(this.options.snap) {
 476       if(Object.isFunction(this.options.snap)) {
 477         p = this.options.snap(p[0],p[1],this);
 478       } else {
 479       if(Object.isArray(this.options.snap)) {
 480         p = p.map( function(v, i) {
 481           return (v/this.options.snap[i]).round()*this.options.snap[i] }.bind(this))
 482       } else {
 483         p = p.map( function(v) {
 484           return (v/this.options.snap).round()*this.options.snap }.bind(this))
 485       }
 486     }}
 487
 488     var style = this.element.style;
 489     if((!this.options.constraint) || (this.options.constraint=='horizontal'))
 490       style.left = p[0] + "px";
 491     if((!this.options.constraint) || (this.options.constraint=='vertical'))
 492       style.top  = p[1] + "px";
 493
 494     if(style.visibility=="hidden") style.visibility = ""; // fix gecko rendering
 495   },
 496
 497   stopScrolling: function() {
 498     if(this.scrollInterval) {
 499       clearInterval(this.scrollInterval);
 500       this.scrollInterval = null;
 501       Draggables._lastScrollPointer = null;
 502     }
 503   },
 504
 505   startScrolling: function(speed) {
 506     if(!(speed[0] || speed[1])) return;
 507     this.scrollSpeed = [speed[0]*this.options.scrollSpeed,speed[1]*this.options.scrollSpeed];
 508     this.lastScrolled = new Date();
 509     this.scrollInterval = setInterval(this.scroll.bind(this), 10);
 510   },
 511
 512   scroll: function() {
 513     var current = new Date();
 514     var delta = current - this.lastScrolled;
 515     this.lastScrolled = current;
 516     if(this.options.scroll == window) {
 517       with (this._getWindowScroll(this.options.scroll)) {
 518         if (this.scrollSpeed[0] || this.scrollSpeed[1]) {
 519           var d = delta / 1000;
 520           this.options.scroll.scrollTo( left + d*this.scrollSpeed[0], top + d*this.scrollSpeed[1] );
 521         }
 522       }
 523     } else {
 524       this.options.scroll.scrollLeft += this.scrollSpeed[0] * delta / 1000;
 525       this.options.scroll.scrollTop  += this.scrollSpeed[1] * delta / 1000;
 526     }
 527
 528     Position.prepare();
 529     Droppables.show(Draggables._lastPointer, this.element);
 530     Draggables.notify('onDrag', this);
 531     if (this._isScrollChild) {
 532       Draggables._lastScrollPointer = Draggables._lastScrollPointer || $A(Draggables._lastPointer);
 533       Draggables._lastScrollPointer[0] += this.scrollSpeed[0] * delta / 1000;
 534       Draggables._lastScrollPointer[1] += this.scrollSpeed[1] * delta / 1000;
 535       if (Draggables._lastScrollPointer[0] < 0)
 536         Draggables._lastScrollPointer[0] = 0;
 537       if (Draggables._lastScrollPointer[1] < 0)
 538         Draggables._lastScrollPointer[1] = 0;
 539       this.draw(Draggables._lastScrollPointer);
 540     }
 541
 542     if(this.options.change) this.options.change(this);
 543   },
 544
 545   _getWindowScroll: function(w) {
 546     var T, L, W, H;
 547     with (w.document) {
 548       if (w.document.documentElement && documentElement.scrollTop) {
 549         T = documentElement.scrollTop;
 550         L = documentElement.scrollLeft;
 551       } else if (w.document.body) {
 552         T = body.scrollTop;
 553         L = body.scrollLeft;
 554       }
 555       if (w.innerWidth) {
 556         W = w.innerWidth;
 557         H = w.innerHeight;
 558       } else if (w.document.documentElement && documentElement.clientWidth) {
 559         W = documentElement.clientWidth;
 560         H = documentElement.clientHeight;
 561       } else {
 562         W = body.offsetWidth;
 563         H = body.offsetHeight
 564       }
 565     }
 566     return { top: T, left: L, width: W, height: H };
 567   }
 568 });
 569
 570 Draggable._dragging = { };
 571
 572 /*--------------------------------------------------------------------------*/
 573
 574 var SortableObserver = Class.create({
 575   initialize: function(element, observer) {
 576     this.element   = $(element);
 577     this.observer  = observer;
 578     this.lastValue = Sortable.serialize(this.element);
 579   },
 580
 581   onStart: function() {
 582     this.lastValue = Sortable.serialize(this.element);
 583   },
 584
 585   onEnd: function() {
 586     Sortable.unmark();
 587     if(this.lastValue != Sortable.serialize(this.element))
 588       this.observer(this.element)
 589   }
 590 });
 591
 592 var Sortable = {
 593   SERIALIZE_RULE: /^[^_\-](?:[A-Za-z0-9\-\_]*)[_](.*)$/,
 594
 595   sortables: { },
 596
 597   _findRootElement: function(element) {
 598     while (element.tagName.toUpperCase() != "BODY") {
 599       if(element.id && Sortable.sortables[element.id]) return element;
 600       element = element.parentNode;
 601     }
 602   },
 603
 604   options: function(element) {
 605     element = Sortable._findRootElement($(element));
 606     if(!element) return;
 607     return Sortable.sortables[element.id];
 608   },
 609
 610   destroy: function(element){
 611     var s = Sortable.options(element);
 612
 613     if(s) {
 614       Draggables.removeObserver(s.element);
 615       s.droppables.each(function(d){ Droppables.remove(d) });
 616       s.draggables.invoke('destroy');
 617
 618       delete Sortable.sortables[s.element.id];
 619     }
 620   },
 621
 622   create: function(element) {
 623     element = $(element);
 624     var options = Object.extend({
 625       element:     element,
 626       tag:         'li',       // assumes li children, override with tag: 'tagname'
 627       dropOnEmpty: false,
 628       tree:        false,
 629       treeTag:     'ul',
 630       overlap:     'vertical', // one of 'vertical', 'horizontal'
 631       constraint:  'vertical', // one of 'vertical', 'horizontal', false
 632       containment: element,    // also takes array of elements (or id's); or false
 633       handle:      false,      // or a CSS class
 634       only:        false,
 635       delay:       0,
 636       hoverclass:  null,
 637       ghosting:    false,
 638       quiet:       false,
 639       scroll:      false,
 640       scrollSensitivity: 20,
 641       scrollSpeed: 15,
 642       format:      this.SERIALIZE_RULE,
 643
 644       // these take arrays of elements or ids and can be
 645       // used for better initialization performance
 646       elements:    false,
 647       handles:     false,
 648
 649       onChange:    Prototype.emptyFunction,
 650       onUpdate:    Prototype.emptyFunction
 651     }, arguments[1] || { });
 652
 653     // clear any old sortable with same element
 654     this.destroy(element);
 655
 656     // build options for the draggables
 657     var options_for_draggable = {
 658       revert:      true,
 659       quiet:       options.quiet,
 660       scroll:      options.scroll,
 661       scrollSpeed: options.scrollSpeed,
 662       scrollSensitivity: options.scrollSensitivity,
 663       delay:       options.delay,
 664       ghosting:    options.ghosting,
 665       constraint:  options.constraint,
 666       handle:      options.handle };
 667
 668     if(options.starteffect)
 669       options_for_draggable.starteffect = options.starteffect;
 670
 671     if(options.reverteffect)
 672       options_for_draggable.reverteffect = options.reverteffect;
 673     else
 674       if(options.ghosting) options_for_draggable.reverteffect = function(element) {
 675         element.style.top  = 0;
 676         element.style.left = 0;
 677       };
 678
 679     if(options.endeffect)
 680       options_for_draggable.endeffect = options.endeffect;
 681
 682     if(options.zindex)
 683       options_for_draggable.zindex = options.zindex;
 684
 685     // build options for the droppables
 686     var options_for_droppable = {
 687       overlap:     options.overlap,
 688       containment: options.containment,
 689       tree:        options.tree,
 690       hoverclass:  options.hoverclass,
 691       onHover:     Sortable.onHover
 692     }
 693
 694     var options_for_tree = {
 695       onHover:      Sortable.onEmptyHover,
 696       overlap:      options.overlap,
 697       containment:  options.containment,
 698       hoverclass:   options.hoverclass
 699     }
 700
 701     // fix for gecko engine
 702     Element.cleanWhitespace(element);
 703
 704     options.draggables = [];
 705     options.droppables = [];
 706
 707     // drop on empty handling
 708     if(options.dropOnEmpty || options.tree) {
 709       Droppables.add(element, options_for_tree);
 710       options.droppables.push(element);
 711     }
 712
 713     (options.elements || this.findElements(element, options) || []).each( function(e,i) {
 714       var handle = options.handles ? $(options.handles[i]) :
 715         (options.handle ? $(e).select('.' + options.handle)[0] : e);
 716       options.draggables.push(
 717         new Draggable(e, Object.extend(options_for_draggable, { handle: handle })));
 718       Droppables.add(e, options_for_droppable);
 719       if(options.tree) e.treeNode = element;
 720       options.droppables.push(e);
 721     });
 722
 723     if(options.tree) {
 724       (Sortable.findTreeElements(element, options) || []).each( function(e) {
 725         Droppables.add(e, options_for_tree);
 726         e.treeNode = element;
 727         options.droppables.push(e);
 728       });
 729     }
 730
 731     // keep reference
 732     this.sortables[element.id] = options;
 733
 734     // for onupdate
 735     Draggables.addObserver(new SortableObserver(element, options.onUpdate));
 736
 737   },
 738
 739   // return all suitable-for-sortable elements in a guaranteed order
 740   findElements: function(element, options) {
 741     return Element.findChildren(
 742       element, options.only, options.tree ? true : false, options.tag);
 743   },
 744
 745   findTreeElements: function(element, options) {
 746     return Element.findChildren(
 747       element, options.only, options.tree ? true : false, options.treeTag);
 748   },
 749
 750   onHover: function(element, dropon, overlap) {
 751     if(Element.isParent(dropon, element)) return;
 752
 753     if(overlap > .33 && overlap < .66 && Sortable.options(dropon).tree) {
 754       return;
 755     } else if(overlap>0.5) {
 756       Sortable.mark(dropon, 'before');
 757       if(dropon.previousSibling != element) {
 758         var oldParentNode = element.parentNode;
 759         element.style.visibility = "hidden"; // fix gecko rendering
 760         dropon.parentNode.insertBefore(element, dropon);
 761         if(dropon.parentNode!=oldParentNode)
 762           Sortable.options(oldParentNode).onChange(element);
 763         Sortable.options(dropon.parentNode).onChange(element);
 764       }
 765     } else {
 766       Sortable.mark(dropon, 'after');
 767       var nextElement = dropon.nextSibling || null;
 768       if(nextElement != element) {
 769         var oldParentNode = element.parentNode;
 770         element.style.visibility = "hidden"; // fix gecko rendering
 771         dropon.parentNode.insertBefore(element, nextElement);
 772         if(dropon.parentNode!=oldParentNode)
 773           Sortable.options(oldParentNode).onChange(element);
 774         Sortable.options(dropon.parentNode).onChange(element);
 775       }
 776     }
 777   },
 778
 779   onEmptyHover: function(element, dropon, overlap) {
 780     var oldParentNode = element.parentNode;
 781     var droponOptions = Sortable.options(dropon);
 782
 783     if(!Element.isParent(dropon, element)) {
 784       var index;
 785
 786       var children = Sortable.findElements(dropon, {tag: droponOptions.tag, only: droponOptions.only});
 787       var child = null;
 788
 789       if(children) {
 790         var offset = Element.offsetSize(dropon, droponOptions.overlap) * (1.0 - overlap);
 791
 792         for (index = 0; index < children.length; index += 1) {
 793           if (offset - Element.offsetSize (children[index], droponOptions.overlap) >= 0) {
 794             offset -= Element.offsetSize (children[index], droponOptions.overlap);
 795           } else if (offset - (Element.offsetSize (children[index], droponOptions.overlap) / 2) >= 0) {
 796             child = index + 1 < children.length ? children[index + 1] : null;
 797             break;
 798           } else {
 799             child = children[index];
 800             break;
 801           }
 802         }
 803       }
 804
 805       dropon.insertBefore(element, child);
 806
 807       Sortable.options(oldParentNode).onChange(element);
 808       droponOptions.onChange(element);
 809     }
 810   },
 811
 812   unmark: function() {
 813     if(Sortable._marker) Sortable._marker.hide();
 814   },
 815
 816   mark: function(dropon, position) {
 817     // mark on ghosting only
 818     var sortable = Sortable.options(dropon.parentNode);
 819     if(sortable && !sortable.ghosting) return;
 820
 821     if(!Sortable._marker) {
 822       Sortable._marker =
 823         ($('dropmarker') || Element.extend(document.createElement('DIV'))).
 824           hide().addClassName('dropmarker').setStyle({position:'absolute'});
 825       document.getElementsByTagName("body").item(0).appendChild(Sortable._marker);
 826     }
 827     var offsets = Position.cumulativeOffset(dropon);
 828     Sortable._marker.setStyle({left: offsets[0]+'px', top: offsets[1] + 'px'});
 829
 830     if(position=='after')
 831       if(sortable.overlap == 'horizontal')
 832         Sortable._marker.setStyle({left: (offsets[0]+dropon.clientWidth) + 'px'});
 833       else
 834         Sortable._marker.setStyle({top: (offsets[1]+dropon.clientHeight) + 'px'});
 835
 836     Sortable._marker.show();
 837   },
 838
 839   _tree: function(element, options, parent) {
 840     var children = Sortable.findElements(element, options) || [];
 841
 842     for (var i = 0; i < children.length; ++i) {
 843       var match = children[i].id.match(options.format);
 844
 845       if (!match) continue;
 846
 847       var child = {
 848         id: encodeURIComponent(match ? match[1] : null),
 849         element: element,
 850         parent: parent,
 851         children: [],
 852         position: parent.children.length,
 853         container: $(children[i]).down(options.treeTag)
 854       }
 855
 856       /* Get the element containing the children and recurse over it */
 857       if (child.container)
 858         this._tree(child.container, options, child)
 859
 860       parent.children.push (child);
 861     }
 862
 863     return parent;
 864   },
 865
 866   tree: function(element) {
 867     element = $(element);
 868     var sortableOptions = this.options(element);
 869     var options = Object.extend({
 870       tag: sortableOptions.tag,
 871       treeTag: sortableOptions.treeTag,
 872       only: sortableOptions.only,
 873       name: element.id,
 874       format: sortableOptions.format
 875     }, arguments[1] || { });
 876
 877     var root = {
 878       id: null,
 879       parent: null,
 880       children: [],
 881       container: element,
 882       position: 0
 883     }
 884
 885     return Sortable._tree(element, options, root);
 886   },
 887
 888   /* Construct a [i] index for a particular node */
 889   _constructIndex: function(node) {
 890     var index = '';
 891     do {
 892       if (node.id) index = '[' + node.position + ']' + index;
 893     } while ((node = node.parent) != null);
 894     return index;
 895   },
 896
 897   sequence: function(element) {
 898     element = $(element);
 899     var options = Object.extend(this.options(element), arguments[1] || { });
 900
 901     return $(this.findElements(element, options) || []).map( function(item) {
 902       return item.id.match(options.format) ? item.id.match(options.format)[1] : '';
 903     });
 904   },
 905
 906   setSequence: function(element, new_sequence) {
 907     element = $(element);
 908     var options = Object.extend(this.options(element), arguments[2] || { });
 909
 910     var nodeMap = { };
 911     this.findElements(element, options).each( function(n) {
 912         if (n.id.match(options.format))
 913             nodeMap[n.id.match(options.format)[1]] = [n, n.parentNode];
 914         n.parentNode.removeChild(n);
 915     });
 916
 917     new_sequence.each(function(ident) {
 918       var n = nodeMap[ident];
 919       if (n) {
 920         n[1].appendChild(n[0]);
 921         delete nodeMap[ident];
 922       }
 923     });
 924   },
 925
 926   serialize: function(element) {
 927     element = $(element);
 928     var options = Object.extend(Sortable.options(element), arguments[1] || { });
 929     var name = encodeURIComponent(
 930       (arguments[1] && arguments[1].name) ? arguments[1].name : element.id);
 931
 932     if (options.tree) {
 933       return Sortable.tree(element, arguments[1]).children.map( function (item) {
 934         return [name + Sortable._constructIndex(item) + "[id]=" +
 935                 encodeURIComponent(item.id)].concat(item.children.map(arguments.callee));
 936       }).flatten().join('&');
 937     } else {
 938       return Sortable.sequence(element, arguments[1]).map( function(item) {
 939         return name + "[]=" + encodeURIComponent(item);
 940       }).join('&');
 941     }
 942   }
 943 }
 944
 945 // Returns true if child is contained within element
 946 Element.isParent = function(child, element) {
 947   if (!child.parentNode || child == element) return false;
 948   if (child.parentNode == element) return true;
 949   return Element.isParent(child.parentNode, element);
 950 }
 951
 952 Element.findChildren = function(element, only, recursive, tagName) {
 953   if(!element.hasChildNodes()) return null;
 954   tagName = tagName.toUpperCase();
 955   if(only) only = [only].flatten();
 956   var elements = [];
 957   $A(element.childNodes).each( function(e) {
 958     if(e.tagName && e.tagName.toUpperCase()==tagName &&
 959       (!only || (Element.classNames(e).detect(function(v) { return only.include(v) }))))
 960         elements.push(e);
 961     if(recursive) {
 962       var grandchildren = Element.findChildren(e, only, recursive, tagName);
 963       if(grandchildren) elements.push(grandchildren);
 964     }
 965   });
 966
 967   return (elements.length>0 ? elements.flatten() : []);
 968 }
 969
 970 Element.offsetSize = function (element, type) {
 971   return element['offset' + ((type=='vertical' || type=='height') ? 'Height' : 'Width')];
 972 }