/* Copyright (c) 2006 Kelvin Luck (kelvin AT kelvinluck DOT com || http://www.kelvinluck.com)
 * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php) 
 * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses.
 * 
 * See http://kelvinluck.com/assets/jquery/jScrollPane/
 * $Id: jScrollPane.js 845 2007-01-02 12:08:44Z kelvin $
 */

jQuery.fn.jScrollPane=function(settings){settings=jQuery.extend({scrollbarWidth:10,scrollbarMargin:5,wheelSpeed:18},settings);return this.each(function(){var $this=jQuery(this);if(jQuery(this).parent().is('.jScrollPaneContainer')){var $c=jQuery(this).parent();var paneWidth=$c.innerWidth();var paneHeight=$c.outerHeight();if($c.unmousewheel){$c.unmousewheel()}jQuery('>.jScrollPaneTrack',$c).remove();$this.css({'top':0})}else{this.originalPadding=$this.css('padding');this.originalSidePaddingTotal=(parseInt($this.css('paddingLeft'))||0)+(parseInt($this.css('paddingRight'))||0);var paneWidth=$this.innerWidth();var paneHeight=$this.innerHeight();$this.wrap(jQuery('<div>').attr({'className':'jScrollPaneContainer'}).css({'height':paneHeight+'px','width':paneWidth+'px'}))}var p=this.originalSidePaddingTotal;$this.css({'height':'auto','width':paneWidth-settings.scrollbarWidth-settings.scrollbarMargin-p+'px','paddingRight':settings.scrollbarMargin+'px'});var contentHeight=$this.outerHeight();var percentInView=paneHeight/contentHeight;if(percentInView<.98){var $container=$this.parent();$container.append(jQuery('<div>').attr({'className':'jScrollPaneTrack'}).css({'width':settings.scrollbarWidth+'px'}).append(jQuery('<div>').attr({'className':'jScrollPaneDrag'}).css({'width':settings.scrollbarWidth+'px'})));var $pane=jQuery(this).css({'position':'absolute','overflow':'visible'});var currentOffset;var maxY;var mouseWheelMultiplier;var dragPosition=0;var dragMiddle=percentInView*paneHeight/2;var getPos=function(event,c){var p=c=='X'?'Left':'Top';return event['page'+c]||(event['client'+c]+(document.documentElement['scroll'+p]||document.body['scroll'+p]))||0};var ignoreNativeDrag=function(){return false};var initDrag=function(){currentOffset=$drag.offset();currentOffset.top-=dragPosition;maxY=paneHeight-currentOffset.height;mouseWheelMultiplier=2*settings.wheelSpeed*maxY/contentHeight};var onStartDrag=function(event){initDrag();dragMiddle=getPos(event,'Y')-dragPosition-currentOffset.top;jQuery('body').bind('mouseup',onStopDrag).bind('mousemove',updateScroll);if(jQuery.browser.msie){jQuery('body').bind('dragstart',ignoreNativeDrag).bind('selectstart',ignoreNativeDrag)}return false};var onStopDrag=function(){jQuery('body').unbind('mouseup',onStopDrag).unbind('mousemove',updateScroll);dragMiddle=percentInView*paneHeight/2;if(jQuery.browser.msie){jQuery('body').unbind('dragstart',ignoreNativeDrag).unbind('selectstart',ignoreNativeDrag)}};var positionDrag=function(destY){destY=destY<0?0:(destY>maxY?maxY:destY);dragPosition=destY;$drag.css({'top':destY+'px'});var p=destY/maxY;$pane.css({'top':((paneHeight-contentHeight)*p)+'px'})};var updateScroll=function(e){positionDrag(getPos(e,'Y')-currentOffset.top-dragMiddle)};var $drag=jQuery('>.jScrollPaneTrack .jScrollPaneDrag',$container);$drag.css({'height':(percentInView*paneHeight)+'px'}).bind('mousedown',onStartDrag);var trackScrollInterval;var trackScrollInc;var trackScrollMousePos;var doTrackScroll=function(){if(trackScrollInc>8||trackScrollInc%4==0){positionDrag((dragPosition-((dragPosition-trackScrollMousePos)/2)))}trackScrollInc++};var onStopTrackClick=function(){clearInterval(trackScrollInterval);jQuery('body').unbind('mouseup',onStopTrackClick).unbind('mousemove',onTrackMouseMove)};var onTrackMouseMove=function(event){trackScrollMousePos=getPos(event,'Y')-currentOffset.top-dragMiddle};var onTrackClick=function(event){initDrag();onTrackMouseMove(event);trackScrollInc=0;trackScrollInterval=setInterval(doTrackScroll,100);jQuery('body').bind('mouseup',onStopTrackClick).bind('mousemove',onTrackMouseMove)};var $track=jQuery('>.jScrollPaneTrack',$container);$track.bind('mousedown',onTrackClick);if($container.mousewheel){$container.mousewheel(function(event,delta){initDrag();var d=dragPosition;positionDrag(dragPosition-delta*mouseWheelMultiplier);if(d!=dragPosition){if(event.preventDefault){event.preventDefault()}else{event.returnValue=false}return false}return true},false)}initDrag()}else{$this.css({'height':paneHeight+'px','width':paneWidth-this.originalSidePaddingTotal+'px','padding':this.originalPadding})}})}