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/public/dragdrop.js

http://github.com/mtravers/wuwei
JavaScript | 972 lines | 786 code | 161 blank | 25 comment | 219 complexity | b2a7b9d3d5c10565fd9ff7c72702603e MD5 | raw file
  1// Copyright (c) 2005-2010 Thomas Fuchs (http://script.aculo.us, http://mir.aculo.us)
  2//
  3// script.aculo.us is freely distributable under the terms of an MIT-style license.
  4// For details, see the script.aculo.us web site: http://script.aculo.us/
  5
  6if(Object.isUndefined(Effect))
  7  throw("dragdrop.js requires including script.aculo.us' effects.js library");
  8
  9var Droppables = {
 10  drops: [],
 11
 12  remove: function(element) {
 13    this.drops = this.drops.reject(function(d) { return d.element==$(element) });
 14  },
 15
 16  add: function(element) {
 17    element = $(element);
 18    var options = Object.extend({
 19      greedy:     true,
 20      hoverclass: null,
 21      tree:       false
 22    }, arguments[1] || { });
 23
 24    // cache containers
 25    if(options.containment) {
 26      options._containers = [];
 27      var containment = options.containment;
 28      if(Object.isArray(containment)) {
 29        containment.each( function(c) { options._containers.push($(c)) });
 30      } else {
 31        options._containers.push($(containment));
 32      }
 33    }
 34
 35    if(options.accept) options.accept = [options.accept].flatten();
 36
 37    Element.makePositioned(element); // fix IE
 38    options.element = element;
 39
 40    this.drops.push(options);
 41  },
 42
 43  findDeepestChild: function(drops) {
 44    deepest = drops[0];
 45
 46    for (i = 1; i < drops.length; ++i)
 47      if (Element.isParent(drops[i].element, deepest.element))
 48        deepest = drops[i];
 49
 50    return deepest;
 51  },
 52
 53  isContained: function(element, drop) {
 54    var containmentNode;
 55    if(drop.tree) {
 56      containmentNode = element.treeNode;
 57    } else {
 58      containmentNode = element.parentNode;
 59    }
 60    return drop._containers.detect(function(c) { return containmentNode == c });
 61  },
 62
 63  isAffected: function(point, element, drop) {
 64    return (
 65      (drop.element!=element) &&
 66      ((!drop._containers) ||
 67        this.isContained(element, drop)) &&
 68      ((!drop.accept) ||
 69        (Element.classNames(element).detect(
 70          function(v) { return drop.accept.include(v) } ) )) &&
 71      Position.within(drop.element, point[0], point[1]) );
 72  },
 73
 74  deactivate: function(drop) {
 75    if(drop.hoverclass)
 76      Element.removeClassName(drop.element, drop.hoverclass);
 77    this.last_active = null;
 78  },
 79
 80  activate: function(drop) {
 81    if(drop.hoverclass)
 82      Element.addClassName(drop.element, drop.hoverclass);
 83    this.last_active = drop;
 84  },
 85
 86  show: function(point, element) {
 87    if(!this.drops.length) return;
 88    var drop, affected = [];
 89
 90    this.drops.each( function(drop) {
 91      if(Droppables.isAffected(point, element, drop))
 92        affected.push(drop);
 93    });
 94
 95    if(affected.length>0)
 96      drop = Droppables.findDeepestChild(affected);
 97
 98    if(this.last_active && this.last_active != drop) this.deactivate(this.last_active);
 99    if (drop) {
100      Position.within(drop.element, point[0], point[1]);
101      if(drop.onHover)
102        drop.onHover(element, drop.element, Position.overlap(drop.overlap, drop.element));
103
104      if (drop != this.last_active) Droppables.activate(drop);
105    }
106  },
107
108  fire: function(event, element) {
109    if(!this.last_active) return;
110    Position.prepare();
111
112    if (this.isAffected([Event.pointerX(event), Event.pointerY(event)], element, this.last_active))
113      if (this.last_active.onDrop) {
114        this.last_active.onDrop(element, this.last_active.element, event);
115        return true;
116      }
117  },
118
119  reset: function() {
120    if(this.last_active)
121      this.deactivate(this.last_active);
122  }
123};
124
125var Draggables = {
126  drags: [],
127  observers: [],
128
129  register: function(draggable) {
130    if(this.drags.length == 0) {
131      this.eventMouseUp   = this.endDrag.bindAsEventListener(this);
132      this.eventMouseMove = this.updateDrag.bindAsEventListener(this);
133      this.eventKeypress  = this.keyPress.bindAsEventListener(this);
134
135      Event.observe(document, "mouseup", this.eventMouseUp);
136      Event.observe(document, "mousemove", this.eventMouseMove);
137      Event.observe(document, "keypress", this.eventKeypress);
138    }
139    this.drags.push(draggable);
140  },
141
142  unregister: function(draggable) {
143    this.drags = this.drags.reject(function(d) { return d==draggable });
144    if(this.drags.length == 0) {
145      Event.stopObserving(document, "mouseup", this.eventMouseUp);
146      Event.stopObserving(document, "mousemove", this.eventMouseMove);
147      Event.stopObserving(document, "keypress", this.eventKeypress);
148    }
149  },
150
151  activate: function(draggable) {
152    if(draggable.options.delay) {
153      this._timeout = setTimeout(function() {
154        Draggables._timeout = null;
155        window.focus();
156        Draggables.activeDraggable = draggable;
157      }.bind(this), draggable.options.delay);
158    } else {
159      window.focus(); // allows keypress events if window isn't currently focused, fails for Safari
160      this.activeDraggable = draggable;
161    }
162  },
163
164  deactivate: function() {
165    this.activeDraggable = null;
166  },
167
168  updateDrag: function(event) {
169    if(!this.activeDraggable) return;
170    var pointer = [Event.pointerX(event), Event.pointerY(event)];
171    // Mozilla-based browsers fire successive mousemove events with
172    // the same coordinates, prevent needless redrawing (moz bug?)
173    if(this._lastPointer && (this._lastPointer.inspect() == pointer.inspect())) return;
174    this._lastPointer = pointer;
175
176    this.activeDraggable.updateDrag(event, pointer);
177  },
178
179  endDrag: function(event) {
180    if(this._timeout) {
181      clearTimeout(this._timeout);
182      this._timeout = null;
183    }
184    if(!this.activeDraggable) return;
185    this._lastPointer = null;
186    this.activeDraggable.endDrag(event);
187    this.activeDraggable = null;
188  },
189
190  keyPress: function(event) {
191    if(this.activeDraggable)
192      this.activeDraggable.keyPress(event);
193  },
194
195  addObserver: function(observer) {
196    this.observers.push(observer);
197    this._cacheObserverCallbacks();
198  },
199
200  removeObserver: function(element) {  // element instead of observer fixes mem leaks
201    this.observers = this.observers.reject( function(o) { return o.element==element });
202    this._cacheObserverCallbacks();
203  },
204
205  notify: function(eventName, draggable, event) {  // 'onStart', 'onEnd', 'onDrag'
206    if(this[eventName+'Count'] > 0)
207      this.observers.each( function(o) {
208        if(o[eventName]) o[eventName](eventName, draggable, event);
209      });
210    if(draggable.options[eventName]) draggable.options[eventName](draggable, event);
211  },
212
213  _cacheObserverCallbacks: function() {
214    ['onStart','onEnd','onDrag'].each( function(eventName) {
215      Draggables[eventName+'Count'] = Draggables.observers.select(
216        function(o) { return o[eventName]; }
217      ).length;
218    });
219  }
220};
221
222/*--------------------------------------------------------------------------*/
223
224var Draggable = Class.create({
225  initialize: function(element) {
226    var defaults = {
227      handle: false,
228      reverteffect: function(element, top_offset, left_offset) {
229        var dur = Math.sqrt(Math.abs(top_offset^2)+Math.abs(left_offset^2))*0.02;
230        new Effect.Move(element, { x: -left_offset, y: -top_offset, duration: dur,
231          queue: {scope:'_draggable', position:'end'}
232        });
233      },
234      endeffect: function(element) {
235        var toOpacity = Object.isNumber(element._opacity) ? element._opacity : 1.0;
236        new Effect.Opacity(element, {duration:0.2, from:0.7, to:toOpacity,
237          queue: {scope:'_draggable', position:'end'},
238          afterFinish: function(){
239            Draggable._dragging[element] = false
240          }
241        });
242      },
243      zindex: 1000,
244      revert: false,
245      quiet: false,
246      scroll: false,
247      scrollSensitivity: 20,
248      scrollSpeed: 15,
249      snap: false,  // false, or xy or [x,y] or function(x,y){ return [x,y] }
250      delay: 0
251    };
252
253    if(!arguments[1] || Object.isUndefined(arguments[1].endeffect))
254      Object.extend(defaults, {
255        starteffect: function(element) {
256          element._opacity = Element.getOpacity(element);
257          Draggable._dragging[element] = true;
258          new Effect.Opacity(element, {duration:0.2, from:element._opacity, to:0.7});
259        }
260      });
261
262    var options = Object.extend(defaults, arguments[1] || { });
263
264    this.element = $(element);
265
266    if(options.handle && Object.isString(options.handle))
267      this.handle = this.element.down('.'+options.handle, 0);
268
269    if(!this.handle) this.handle = $(options.handle);
270    if(!this.handle) this.handle = this.element;
271
272    if(options.scroll && !options.scroll.scrollTo && !options.scroll.outerHTML) {
273      options.scroll = $(options.scroll);
274      this._isScrollChild = Element.childOf(this.element, options.scroll);
275    }
276
277    Element.makePositioned(this.element); // fix IE
278
279    this.options  = options;
280    this.dragging = false;
281
282    this.eventMouseDown = this.initDrag.bindAsEventListener(this);
283    Event.observe(this.handle, "mousedown", this.eventMouseDown);
284
285    Draggables.register(this);
286  },
287
288  destroy: function() {
289    Event.stopObserving(this.handle, "mousedown", this.eventMouseDown);
290    Draggables.unregister(this);
291  },
292
293  currentDelta: function() {
294    return([
295      parseInt(Element.getStyle(this.element,'left') || '0'),
296      parseInt(Element.getStyle(this.element,'top') || '0')]);
297  },
298
299  initDrag: function(event) {
300    if(!Object.isUndefined(Draggable._dragging[this.element]) &&
301      Draggable._dragging[this.element]) return;
302    if(Event.isLeftClick(event)) {
303      // abort on form elements, fixes a Firefox issue
304      var src = Event.element(event);
305      if((tag_name = src.tagName.toUpperCase()) && (
306        tag_name=='INPUT' ||
307        tag_name=='SELECT' ||
308        tag_name=='OPTION' ||
309        tag_name=='BUTTON' ||
310        tag_name=='TEXTAREA')) return;
311
312      var pointer = [Event.pointerX(event), Event.pointerY(event)];
313      var pos     = this.element.cumulativeOffset();
314      this.offset = [0,1].map( function(i) { return (pointer[i] - pos[i]) });
315
316      Draggables.activate(this);
317      Event.stop(event);
318    }
319  },
320
321  startDrag: function(event) {
322    this.dragging = true;
323    if(!this.delta)
324      this.delta = this.currentDelta();
325
326    if(this.options.zindex) {
327      this.originalZ = parseInt(Element.getStyle(this.element,'z-index') || 0);
328      this.element.style.zIndex = this.options.zindex;
329    }
330
331    if(this.options.ghosting) {
332      this._clone = this.element.cloneNode(true);
333      this._originallyAbsolute = (this.element.getStyle('position') == 'absolute');
334      if (!this._originallyAbsolute)
335        Position.absolutize(this.element);
336      this.element.parentNode.insertBefore(this._clone, this.element);
337    }
338
339    if(this.options.scroll) {
340      if (this.options.scroll == window) {
341        var where = this._getWindowScroll(this.options.scroll);
342        this.originalScrollLeft = where.left;
343        this.originalScrollTop = where.top;
344      } else {
345        this.originalScrollLeft = this.options.scroll.scrollLeft;
346        this.originalScrollTop = this.options.scroll.scrollTop;
347      }
348    }
349
350    Draggables.notify('onStart', this, event);
351
352    if(this.options.starteffect) this.options.starteffect(this.element);
353  },
354
355  updateDrag: function(event, pointer) {
356    if(!this.dragging) this.startDrag(event);
357
358    if(!this.options.quiet){
359      Position.prepare();
360      Droppables.show(pointer, this.element);
361    }
362
363    Draggables.notify('onDrag', this, event);
364
365    this.draw(pointer);
366    if(this.options.change) this.options.change(this);
367
368    if(this.options.scroll) {
369      this.stopScrolling();
370
371      var p;
372      if (this.options.scroll == window) {
373        with(this._getWindowScroll(this.options.scroll)) { p = [ left, top, left+width, top+height ]; }
374      } else {
375        p = Position.page(this.options.scroll).toArray();
376        p[0] += this.options.scroll.scrollLeft + Position.deltaX;
377        p[1] += this.options.scroll.scrollTop + Position.deltaY;
378        p.push(p[0]+this.options.scroll.offsetWidth);
379        p.push(p[1]+this.options.scroll.offsetHeight);
380      }
381      var speed = [0,0];
382      if(pointer[0] < (p[0]+this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[0]+this.options.scrollSensitivity);
383      if(pointer[1] < (p[1]+this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[1]+this.options.scrollSensitivity);
384      if(pointer[0] > (p[2]-this.options.scrollSensitivity)) speed[0] = pointer[0]-(p[2]-this.options.scrollSensitivity);
385      if(pointer[1] > (p[3]-this.options.scrollSensitivity)) speed[1] = pointer[1]-(p[3]-this.options.scrollSensitivity);
386      this.startScrolling(speed);
387    }
388
389    // fix AppleWebKit rendering
390    if(Prototype.Browser.WebKit) window.scrollBy(0,0);
391
392    Event.stop(event);
393  },
394
395  finishDrag: function(event, success) {
396    this.dragging = false;
397
398    if(this.options.quiet){
399      Position.prepare();
400      var pointer = [Event.pointerX(event), Event.pointerY(event)];
401      Droppables.show(pointer, this.element);
402    }
403
404    if(this.options.ghosting) {
405      if (!this._originallyAbsolute)
406        Position.relativize(this.element);
407      delete this._originallyAbsolute;
408      Element.remove(this._clone);
409      this._clone = null;
410    }
411
412    var dropped = false;
413    if(success) {
414      dropped = Droppables.fire(event, this.element);
415      if (!dropped) dropped = false;
416    }
417    if(dropped && this.options.onDropped) this.options.onDropped(this.element);
418    Draggables.notify('onEnd', this, event);
419
420    var revert = this.options.revert;
421    if(revert && Object.isFunction(revert)) revert = revert(this.element);
422
423    var d = this.currentDelta();
424    if(revert && this.options.reverteffect) {
425      if (dropped == 0 || revert != 'failure')
426        this.options.reverteffect(this.element,
427          d[1]-this.delta[1], d[0]-this.delta[0]);
428    } else {
429      this.delta = d;
430    }
431
432    if(this.options.zindex)
433      this.element.style.zIndex = this.originalZ;
434
435    if(this.options.endeffect)
436      this.options.endeffect(this.element);
437
438    Draggables.deactivate(this);
439    Droppables.reset();
440  },
441
442  keyPress: function(event) {
443    if(event.keyCode!=Event.KEY_ESC) return;
444    this.finishDrag(event, false);
445    Event.stop(event);
446  },
447
448  endDrag: function(event) {
449    if(!this.dragging) return;
450    this.stopScrolling();
451    this.finishDrag(event, true);
452    Event.stop(event);
453  },
454
455  draw: function(point) {
456    var pos = this.element.cumulativeOffset();
457    if(this.options.ghosting) {
458      var r   = Position.realOffset(this.element);
459      pos[0] += r[0] - Position.deltaX; pos[1] += r[1] - Position.deltaY;
460    }
461
462    var d = this.currentDelta();
463    pos[0] -= d[0]; pos[1] -= d[1];
464
465    if(this.options.scroll && (this.options.scroll != window && this._isScrollChild)) {
466      pos[0] -= this.options.scroll.scrollLeft-this.originalScrollLeft;
467      pos[1] -= this.options.scroll.scrollTop-this.originalScrollTop;
468    }
469
470    var p = [0,1].map(function(i){
471      return (point[i]-pos[i]-this.offset[i])
472    }.bind(this));
473
474    if(this.options.snap) {
475      if(Object.isFunction(this.options.snap)) {
476        p = this.options.snap(p[0],p[1],this);
477      } else {
478      if(Object.isArray(this.options.snap)) {
479        p = p.map( function(v, i) {
480          return (v/this.options.snap[i]).round()*this.options.snap[i] }.bind(this));
481      } else {
482        p = p.map( function(v) {
483          return (v/this.options.snap).round()*this.options.snap }.bind(this));
484      }
485    }}
486
487    var style = this.element.style;
488    if((!this.options.constraint) || (this.options.constraint=='horizontal'))
489      style.left = p[0] + "px";
490    if((!this.options.constraint) || (this.options.constraint=='vertical'))
491      style.top  = p[1] + "px";
492
493    if(style.visibility=="hidden") style.visibility = ""; // fix gecko rendering
494  },
495
496  stopScrolling: function() {
497    if(this.scrollInterval) {
498      clearInterval(this.scrollInterval);
499      this.scrollInterval = null;
500      Draggables._lastScrollPointer = null;
501    }
502  },
503
504  startScrolling: function(speed) {
505    if(!(speed[0] || speed[1])) return;
506    this.scrollSpeed = [speed[0]*this.options.scrollSpeed,speed[1]*this.options.scrollSpeed];
507    this.lastScrolled = new Date();
508    this.scrollInterval = setInterval(this.scroll.bind(this), 10);
509  },
510
511  scroll: function() {
512    var current = new Date();
513    var delta = current - this.lastScrolled;
514    this.lastScrolled = current;
515    if(this.options.scroll == window) {
516      with (this._getWindowScroll(this.options.scroll)) {
517        if (this.scrollSpeed[0] || this.scrollSpeed[1]) {
518          var d = delta / 1000;
519          this.options.scroll.scrollTo( left + d*this.scrollSpeed[0], top + d*this.scrollSpeed[1] );
520        }
521      }
522    } else {
523      this.options.scroll.scrollLeft += this.scrollSpeed[0] * delta / 1000;
524      this.options.scroll.scrollTop  += this.scrollSpeed[1] * delta / 1000;
525    }
526
527    Position.prepare();
528    Droppables.show(Draggables._lastPointer, this.element);
529    Draggables.notify('onDrag', this);
530    if (this._isScrollChild) {
531      Draggables._lastScrollPointer = Draggables._lastScrollPointer || $A(Draggables._lastPointer);
532      Draggables._lastScrollPointer[0] += this.scrollSpeed[0] * delta / 1000;
533      Draggables._lastScrollPointer[1] += this.scrollSpeed[1] * delta / 1000;
534      if (Draggables._lastScrollPointer[0] < 0)
535        Draggables._lastScrollPointer[0] = 0;
536      if (Draggables._lastScrollPointer[1] < 0)
537        Draggables._lastScrollPointer[1] = 0;
538      this.draw(Draggables._lastScrollPointer);
539    }
540
541    if(this.options.change) this.options.change(this);
542  },
543
544  _getWindowScroll: function(w) {
545    var T, L, W, H;
546    with (w.document) {
547      if (w.document.documentElement && documentElement.scrollTop) {
548        T = documentElement.scrollTop;
549        L = documentElement.scrollLeft;
550      } else if (w.document.body) {
551        T = body.scrollTop;
552        L = body.scrollLeft;
553      }
554      if (w.innerWidth) {
555        W = w.innerWidth;
556        H = w.innerHeight;
557      } else if (w.document.documentElement && documentElement.clientWidth) {
558        W = documentElement.clientWidth;
559        H = documentElement.clientHeight;
560      } else {
561        W = body.offsetWidth;
562        H = body.offsetHeight;
563      }
564    }
565    return { top: T, left: L, width: W, height: H };
566  }
567});
568
569Draggable._dragging = { };
570
571/*--------------------------------------------------------------------------*/
572
573var SortableObserver = Class.create({
574  initialize: function(element, observer) {
575    this.element   = $(element);
576    this.observer  = observer;
577    this.lastValue = Sortable.serialize(this.element);
578  },
579
580  onStart: function() {
581    this.lastValue = Sortable.serialize(this.element);
582  },
583
584  onEnd: function() {
585    Sortable.unmark();
586    if(this.lastValue != Sortable.serialize(this.element))
587      this.observer(this.element)
588  }
589});
590
591var Sortable = {
592  SERIALIZE_RULE: /^[^_\-](?:[A-Za-z0-9\-\_]*)[_](.*)$/,
593
594  sortables: { },
595
596  _findRootElement: function(element) {
597    while (element.tagName.toUpperCase() != "BODY") {
598      if(element.id && Sortable.sortables[element.id]) return element;
599      element = element.parentNode;
600    }
601  },
602
603  options: function(element) {
604    element = Sortable._findRootElement($(element));
605    if(!element) return;
606    return Sortable.sortables[element.id];
607  },
608
609  destroy: function(element){
610    element = $(element);
611    var s = Sortable.sortables[element.id];
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.identify()] = 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 = dropon.cumulativeOffset();
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
946Element.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
952Element.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
970Element.offsetSize = function (element, type) {
971  return element['offset' + ((type=='vertical' || type=='height') ? 'Height' : 'Width')];
972};