/**
 * Isotope v1.5.03
 * An exquisite jQuery plugin for magical layouts
 * http://isotope.metafizzy.co
 *
 * Commercial use requires one-time license fee
 * http://metafizzy.co/#licenses
 *
 * Copyright 2011 David DeSandro / Metafizzy
 */

/*jshint curly: true, eqeqeq: true, forin: false, immed: false, newcap: true, noempty: true, undef: true */
/*global Modernizr: true, jQuery: true */

(function( window, $, undefined ){

  'use strict';

  // helper function
  var capitalize = function( str ) {
    return str.charAt(0).toUpperCase() + str.slice(1);
  };

  // ========================= getStyleProperty by kangax ===============================
  // http://perfectionkills.com/feature-testing-css-properties/

  var prefixes = 'Moz Webkit Khtml O Ms'.split(' ');

  var getStyleProperty = function( propName ) {
    var style = document.documentElement.style,
        prefixed;

    // test standard property first
    if ( typeof style[propName] === 'string' ) {
      return propName;
    }

    // capitalize
    propName = capitalize( propName );

    // test vendor specific properties
    for ( var i=0, len = prefixes.length; i < len; i++ ) {
      prefixed = prefixes[i] + propName;
      if ( typeof style[ prefixed ] === 'string' ) {
        return prefixed;
      }
    }
  };

  var transformProp = getStyleProperty('transform'),
      transitionProp = getStyleProperty('transitionProperty');
      

  // ========================= miniModernizr ===============================
  // <3<3<3 and thanks to Faruk and Paul for doing the heavy lifting

  /*!
   * Modernizr v1.6ish: miniModernizr for Isotope
   * http://www.modernizr.com
   *
   * Developed by: 
   * - Faruk Ates  http://farukat.es/
   * - Paul Irish  http://paulirish.com/
   *
   * Copyright (c) 2009-2010
   * Dual-licensed under the BSD or MIT licenses.
   * http://www.modernizr.com/license/
   */

  /*
   * This version whittles down the script just to check support for
   * CSS transitions, transforms, and 3D transforms.
  */
  
  var tests = {
    csstransforms: function() {
      return !!transformProp;
    },

    csstransforms3d: function() {
      var test = !!getStyleProperty('perspective');
      // double check for Chrome's false positive
      if ( test ) {
        var vendorCSSPrefixes = ' -o- -moz- -ms- -webkit- -khtml- '.split(' '),
            mediaQuery = '@media (' + vendorCSSPrefixes.join('transform-3d),(') + 'modernizr)',
            $style = $('<style>' + mediaQuery + '{#modernizr{height:3px}}' + '</style>')
                        .appendTo('head'),
            $div = $('<div id="modernizr" />').appendTo('html');

        test = $div.height() === 3;

        $div.remove();
        $style.remove();
      }
      return test;
    },

    csstransitions: function() {
      return !!transitionProp;
    }
  };

  if ( window.Modernizr ) {
    // if there's a previous Modernzir, check if there are necessary tests
    for ( var testName in tests) {
      if ( !Modernizr.hasOwnProperty( testName ) ) {
        // if test hasn't been run, use addTest to run it
        Modernizr.addTest( testName, tests[ testName ] );
      }
    }
  } else {
    // or create new mini Modernizr that just has the 3 tests
    window.Modernizr = (function(){

      var miniModernizr = {
            _version : '1.6ish: miniModernizr for Isotope'
          },
          classes = ' ',
          result, testName;

      // Run through tests
      for ( testName in tests) {
        result = tests[ testName ]();
        miniModernizr[ testName ] = result;
        classes += ' ' + ( result ?  '' : 'no-' ) + testName;
      }

      // Add the new classes to the <html> element.
      $('html').addClass( classes );

      return miniModernizr;
    })();
  }



  // ========================= isoTransform ===============================

  /**
   *  provides hooks for .css({ scale: value, translate: [x, y] })
   *  Progressively enhanced CSS transforms
   *  Uses hardware accelerated 3D transforms for Safari
   *  or falls back to 2D transforms.
   */
  
  if ( Modernizr.csstransforms ) {
    
        // i.e. transformFnNotations.scale(0.5) >> 'scale3d( 0.5, 0.5, 1)'
    var transformFnNotations = Modernizr.csstransforms3d ? 
      { // 3D transform functions
        translate : function ( position ) {
          return 'translate3d(' + position[0] + 'px, ' + position[1] + 'px, 0) ';
        },
        scale : function ( scale ) {
          return 'scale3d(' + scale + ', ' + scale + ', 1) ';
        }
      } :
      { // 2D transform functions
        translate : function ( position ) {
          return 'translate(' + position[0] + 'px, ' + position[1] + 'px) ';
        },
        scale : function ( scale ) {
          return 'scale(' + scale + ') ';
        }
      }
    ;

    var setIsoTransform = function ( elem, name, value ) {
          // unpack current transform data
      var data =  $.data( elem, 'isoTransform' ) || {},
          newData = {},
          fnName,
          transformObj = {},
          transformValue;

      // i.e. newData.scale = 0.5
      newData[ name ] = value;
      // extend new value over current data
      $.extend( data, newData );

      for ( fnName in data ) {
        transformValue = data[ fnName ];
        transformObj[ fnName ] = transformFnNotations[ fnName ]( transformValue );
      }

      // get proper order
      // ideally, we could loop through this give an array, but since we only have
      // a couple transforms we're keeping track of, we'll do it like so
      var translateFn = transformObj.translate || '',
          scaleFn = transformObj.scale || '',
          // sorting so translate always comes first
          valueFns = translateFn + scaleFn;

      // set data back in elem
      $.data( elem, 'isoTransform', data );

      // set name to vendor specific property
      elem.style[ transformProp ] = valueFns;
    };
   
    // ==================== scale ===================
  
    $.cssNumber.scale = true;
  
    $.cssHooks.scale = {
      set: function( elem, value ) {
        // uncomment this bit if you want to properly parse strings
        // if ( typeof value === 'string' ) {
        //   value = parseFloat( value );
        // }
        setIsoTransform( elem, 'scale', value );
      },
      get: function( elem, computed ) {
        var transform = $.data( elem, 'isoTransform' );
        return transform && transform.scale ? transform.scale : 1;
      }
    };

    $.fx.step.scale = function( fx ) {
      $.cssHooks.scale.set( fx.elem, fx.now+fx.unit );
    };
  
  
    // ==================== translate ===================
    
    $.cssNumber.translate = true;
  
    $.cssHooks.translate = {
      set: function( elem, value ) {

        // uncomment this bit if you want to properly parse strings
        // if ( typeof value === 'string' ) {
        //   value = value.split(' ');
        // }
        // 
        // var i, val;
        // for ( i = 0; i < 2; i++ ) {
        //   val = value[i];
        //   if ( typeof val === 'string' ) {
        //     val = parseInt( val );
        //   }
        // }

        setIsoTransform( elem, 'translate', value );
      },
    
      get: function( elem, computed ) {
        var transform = $.data( elem, 'isoTransform' );
        return transform && transform.translate ? transform.translate : [ 0, 0 ];
      }
    };

  }
  
  // ========================= get transition-end event ===============================
  var transitionEndEvent, transitionDurProp;
  
  if ( Modernizr.csstransitions ) {
    transitionEndEvent = {
      WebkitTransitionProperty: 'webkitTransitionEnd',  // webkit
      MozTransitionProperty: 'transitionend',
      OTransitionProperty: 'oTransitionEnd',
      transitionProperty: 'transitionEnd'
    }[ transitionProp ];

    transitionDurProp = getStyleProperty('transitionDuration');
  }

  // ========================= smartresize ===============================

  /*
   * smartresize: debounced resize event for jQuery
   *
   * latest version and complete README available on Github:
   * https://github.com/louisremi/jquery.smartresize.js
   *
   * Copyright 2011 @louis_remi
   * Licensed under the MIT license.
   */

  var $event = $.event,
      resizeTimeout;

  $event.special.smartresize = {
    setup: function() {
      $(this).bind( "resize", $event.special.smartresize.handler );
    },
    teardown: function() {
      $(this).unbind( "resize", $event.special.smartresize.handler );
    },
    handler: function( event, execAsap ) {
      // Save the context
      var context = this,
          args = arguments;

      // set correct event type
      event.type = "smartresize";

      if ( resizeTimeout ) { clearTimeout( resizeTimeout ); }
      resizeTimeout = setTimeout(function() {
        jQuery.event.handle.apply( context, args );
      }, execAsap === "execAsap"? 0 : 100 );
    }
  };

  $.fn.smartresize = function( fn ) {
    return fn ? this.bind( "smartresize", fn ) : this.trigger( "smartresize", ["execAsap"] );
  };



// ========================= Isotope ===============================


  // our "Widget" object constructor
  $.Isotope = function( options, element, callback ){
    this.element = $( element );

    this._create( options );
    this._init( callback );
  };
  
  // styles of container element we want to keep track of
  var isoContainerStyles = [ 'overflow', 'position', 'width', 'height' ];
  
  $.Isotope.settings = {
    resizable: true,
    layoutMode : 'masonry',
    containerClass : 'isotope',
    itemClass : 'isotope-item',
    hiddenClass : 'isotope-hidden',
    hiddenStyle : Modernizr.csstransforms && !$.browser.opera ? 
      { opacity : 0, scale : 0.001 } : // browsers support CSS transforms, not Opera
      { opacity : 0 }, // other browsers, including Opera
    visibleStyle : Modernizr.csstransforms && !$.browser.opera ? 
      { opacity : 1, scale : 1 } : // browsers support CSS transforms, not Opera
      { opacity : 1 },  // other browsers, including Opera
    animationEngine : $.browser.opera ? 'jquery' : 'best-available',
    animationOptions: {
      queue: false,
      duration: 800
    },
    sortBy : 'original-order',
    sortAscending : true,
    resizesContainer : true,
    transformsEnabled : true,
    itemPositionDataEnabled: false
  };

  $.Isotope.prototype = {

    // sets up widget
    _create : function( options ) {
      
      this.options = $.extend( {}, $.Isotope.settings, options );
      
      this.styleQueue = [];
      this.elemCount = 0;

      // get original styles in case we re-apply them in .destroy()
      var elemStyle = this.element[0].style;
      this.originalStyle = {};
      for ( var i=0, len = isoContainerStyles.length; i < len; i++ ) {
        var prop = isoContainerStyles[i];
        this.originalStyle[ prop ] = elemStyle[ prop ] || '';
      }
      
      this.element.css({
        overflow : 'hidden',
        position : 'relative'
      });
      
      this._updateAnimationEngine();
      this._updateUsingTransforms();
      
      // sorting
      var originalOrderSorter = {
        'original-order' : function( $elem, instance ) {
          instance.elemCount ++;
          return instance.elemCount;
        },
        random : function() {
          return Math.random();
        }
      };

      this.options.getSortData = $.extend( this.options.getSortData, originalOrderSorter );

      // need to get atoms
      this.reloadItems();
      
      // get top left position of where the bricks should be
      var $cursor = $( document.createElement('div') ).prependTo( this.element );
      this.offset = $cursor.position();
      $cursor.remove();

      // add isotope class first time around
      var instance = this;
      setTimeout( function() {
        instance.element.addClass( instance.options.containerClass );
      }, 0 );
      
      // bind resize method
      if ( this.options.resizable ) {
        $(window).bind( 'smartresize.isotope', function() { 
          instance.resize();
        });
      }
      
      // dismiss all click events from hidden events
      this.element.delegate( '.' + this.options.hiddenClass, 'click', function(){
        return false;
      });
      
    },
    
    _getAtoms : function( $elems ) {
      var selector = this.options.itemSelector,
          // filter & find 
          $atoms = selector ? $elems.filter( selector ).add( $elems.find( selector ) ) : $elems,
          // base style for atoms
          atomStyle = { position: 'absolute' };
          
      if ( this.usingTransforms ) {
        atomStyle.left = 0;
        atomStyle.top = 0;
      }

      $atoms.css( atomStyle ).addClass( this.options.itemClass );

      this.updateSortData( $atoms, true );
      
      return $atoms;
    },
  
    // _init fires when your instance is first created
    // (from the constructor above), and when you
    // attempt to initialize the widget again (by the bridge)
    // after it has already been initialized.
    _init : function( callback ) {
      
      this.$filteredAtoms = this._filter( this.$allAtoms );
      this._sort();
      this.reLayout( callback );

    },

    option : function( opts ){
      // change options AFTER initialization:
      // signature: $('#foo').bar({ cool:false });
      if ( $.isPlainObject( opts ) ){
        this.options = $.extend( true, this.options, opts );

        // trigger _updateOptionName if it exists
        var updateOptionFn;
        for ( var optionName in opts ) {
          updateOptionFn = '_update' + capitalize( optionName );
          if ( this[ updateOptionFn ] ) {
            this[ updateOptionFn ]();
          }
        }
      }
    },
    
    // ====================== updaters ====================== //
    // kind of like setters
    
    _updateAnimationEngine : function() {
      var animationEngine = this.options.animationEngine.toLowerCase().replace( /[ _\-]/g, '');
      // set applyStyleFnName
      switch ( animationEngine ) {
        case 'css' :
        case 'none' :
          this.isUsingJQueryAnimation = false;
          break;
        case 'jquery' :
          this.isUsingJQueryAnimation = true;
          break;
        default : // best available
          this.isUsingJQueryAnimation = !Modernizr.csstransitions;
      }
      
      this._updateUsingTransforms();
    },
    
    _updateTransformsEnabled : function() {
      this._updateUsingTransforms();
    },
    
    _updateUsingTransforms : function() {
      this.usingTransforms = this.options.transformsEnabled && Modernizr.csstransforms && Modernizr.csstransitions && !this.isUsingJQueryAnimation;

      this.getPositionStyles = this.usingTransforms ? this._translate : this._positionAbs;
    },

    
    // ====================== Filtering ======================

    _filter : function( $atoms ) {
      var filter = this.options.filter === '' ? '*' : this.options.filter;

      if ( !filter ) {
        return $atoms;
      }

      var hiddenClass    = this.options.hiddenClass,
          hiddenSelector = '.' + hiddenClass,
          $hiddenAtoms   = $atoms.filter( hiddenSelector ),
          $atomsToShow   = $hiddenAtoms;

      if ( filter !== '*' ) {
        $atomsToShow = $hiddenAtoms.filter( filter );
        var $atomsToHide = $atoms.not( hiddenSelector ).not( filter ).addClass( hiddenClass );
        this.styleQueue.push({ $el: $atomsToHide, style: this.options.hiddenStyle });
      }

      this.styleQueue.push({ $el: $atomsToShow, style: this.options.visibleStyle });
      $atomsToShow.removeClass( hiddenClass );

      return $atoms.filter( filter );
    },
    
    // ====================== Sorting ======================
    
    updateSortData : function( $atoms, isIncrementingElemCount ) {
      var instance = this,
          getSortData = this.options.getSortData,
          $this, sortData;
      $atoms.each(function(){
        $this = $(this);
        sortData = {};
        // get value for sort data based on fn( $elem ) passed in
        for ( var key in getSortData ) {
          if ( !isIncrementingElemCount && key === 'original-order' ) {
            // keep original order original
            sortData[ key ] = $.data( this, 'isotope-sort-data' )[ key ];
          } else {
            sortData[ key ] = getSortData[ key ]( $this, instance );
          }
        }
        // apply sort data to element
        $.data( this, 'isotope-sort-data', sortData );
      });
    },
    
    // used on all the filtered atoms
    _sort : function() {
      
      var sortBy = this.options.sortBy,
          getSorter = this._getSorter,
          sortDir = this.options.sortAscending ? 1 : -1,
          sortFn = function( alpha, beta ) {
            var a = getSorter( alpha, sortBy ),
                b = getSorter( beta, sortBy );
            // fall back to original order if data matches
            if ( a === b && sortBy !== 'original-order') {
              a = getSorter( alpha, 'original-order' );
              b = getSorter( beta, 'original-order' );
            }
            return ( ( a > b ) ? 1 : ( a < b ) ? -1 : 0 ) * sortDir;
          };
      
      this.$filteredAtoms.sort( sortFn );
    },

    _getSorter : function( elem, sortBy ) {
      return $.data( elem, 'isotope-sort-data' )[ sortBy ];
    },

    // ====================== Layout Helpers ======================

    _translate : function( x, y ) {
      return { translate : [ x, y ] };
    },
    
    _positionAbs : function( x, y ) {
      return { left: x, top: y };
    },

    _pushPosition : function( $elem, x, y ) {
      x += this.offset.left;
      y += this.offset.top;
      var position = this.getPositionStyles( x, y );
      this.styleQueue.push({ $el: $elem, style: position });
      if ( this.options.itemPositionDataEnabled ) {
        $elem.data('isotope-item-position', {x: x, y: y} );
      }
    },


    // ====================== General Layout ======================

    // used on collection of atoms (should be filtered, and sorted before )
    // accepts atoms-to-be-laid-out to start with
    layout : function( $elems, callback ) {

      var layoutMode = this.options.layoutMode;

      // layout logic
      this[ '_' +  layoutMode + 'Layout' ]( $elems );
      
      // set the size of the container
      if ( this.options.resizesContainer ) {
        var containerStyle = this[ '_' +  layoutMode + 'GetContainerSize' ]();
        this.styleQueue.push({ $el: this.element, style: containerStyle });
      }

      this._processStyleQueue( $elems, callback );
      
      this.isLaidOut = true;
    },
    
    _processStyleQueue : function( $elems, callback ) {
      // are we animating the layout arrangement?
      // use plugin-ish syntax for css or animate
      var styleFn = !this.isLaidOut ? 'css' : (
            this.isUsingJQueryAnimation ? 'animate' : 'css'
          ),
          animOpts = this.options.animationOptions,
          objStyleFn, processor,
          triggerCallbackNow, callbackFn;

      // default styleQueue processor, may be overwritten down below
      processor = function( i, obj ) {
        obj.$el[ styleFn ]( obj.style, animOpts );
      };

      if ( this._isInserting && this.isUsingJQueryAnimation ) {
        // if using styleQueue to insert items
        processor = function( i, obj ) {
          // only animate if it not being inserted
          objStyleFn = obj.$el.hasClass('no-transition') ? 'css' : styleFn;
          obj.$el[ objStyleFn ]( obj.style, animOpts );
        };
        
      } else if ( callback ) {
        // has callback
        var isCallbackTriggered = false,
            instance = this;
        triggerCallbackNow = true;
        // trigger callback only once
        callbackFn = function() {
          if ( isCallbackTriggered ) {
            return;
          }
          callback.call( instance.element, $elems );
          isCallbackTriggered = true;
        };
        
        if ( this.isUsingJQueryAnimation && styleFn === 'animate' ) {
          // add callback to animation options
          animOpts.complete = callbackFn;
          triggerCallbackNow = false;

        } else if ( Modernizr.csstransitions ) {
          // detect if first item has transition
          var i = 0,
              testElem = this.styleQueue[0].$el,
              styleObj;
          // get first non-empty jQ object
          while ( !testElem.length ) {
            styleObj = this.styleQueue[ i++ ];
            // HACK: sometimes styleQueue[i] is undefined
            if ( !styleObj ) {
              return;
            }
            testElem = styleObj.$el;
          }
          // get transition duration of the first element in that object
          // yeah, this is inexact
          var duration = parseFloat( getComputedStyle( testElem[0] )[ transitionDurProp ] );
          if ( duration > 0 ) {
            processor = function( i, obj ) {
              obj.$el[ styleFn ]( obj.style, animOpts )
                // trigger callback at transition end
                .one( transitionEndEvent, callbackFn );
            };
            triggerCallbackNow = false;
          }
        }
      }

      // process styleQueue
      $.each( this.styleQueue, processor );
      
      if ( triggerCallbackNow ) {
        callbackFn();
      }

      // clear out queue for next time
      this.styleQueue = [];
    },
    
    
    resize : function() {
      if ( this[ '_' + this.options.layoutMode + 'ResizeChanged' ]() ) {
        this.reLayout();
      }
    },
    
    
    reLayout : function( callback ) {
      
      this[ '_' +  this.options.layoutMode + 'Reset' ]();
      this.layout( this.$filteredAtoms, callback );
      
    },
    
    // ====================== Convenience methods ======================
    
    // ====================== Adding items ======================
    
    // adds a jQuery object of items to a isotope container
    addItems : function( $content, callback ) {
      var $newAtoms = this._getAtoms( $content );
      // add new atoms to atoms pools
      this.$allAtoms = this.$allAtoms.add( $newAtoms );

      if ( callback ) {
        callback( $newAtoms );
      }
    },
    
    // convienence method for adding elements properly to any layout
    // positions items, hides them, then animates them back in <--- very sezzy
    insert : function( $content, callback ) {
      // position items
      this.element.append( $content );
      
      var instance = this;
      this.addItems( $content, function( $newAtoms ) {
        var $newFilteredAtoms = instance._filter( $newAtoms, true );
        instance._addHideAppended( $newFilteredAtoms );
        instance._sort();
        instance.reLayout();
        instance._revealAppended( $newFilteredAtoms, callback );
      });
      
    },
    
    // convienence method for working with Infinite Scroll
    appended : function( $content, callback ) {
      var instance = this;
      this.addItems( $content, function( $newAtoms ) {
        instance._addHideAppended( $newAtoms );
        instance.layout( $newAtoms );
        instance._revealAppended( $newAtoms, callback );
      });
    },
    
    // adds new atoms, then hides them before positioning
    _addHideAppended : function( $newAtoms ) {
      this.$filteredAtoms = this.$filteredAtoms.add( $newAtoms );
      $newAtoms.addClass('no-transition');
      
      this._isInserting = true;
      
      // apply hidden styles
      this.styleQueue.push({ $el: $newAtoms, style: this.options.hiddenStyle });
    },
    
    // sets visible style on new atoms
    _revealAppended : function( $newAtoms, callback ) {
      var instance = this;
      // apply visible style after a sec
      setTimeout( function() {
        // enable animation
        $newAtoms.removeClass('no-transition');
        // reveal newly inserted filtered elements
        instance.styleQueue.push({ $el: $newAtoms, style: instance.options.visibleStyle });
        instance._isInserting = false;
        instance._processStyleQueue( $newAtoms, callback );
      }, 10 );
    },
    
    // gathers all atoms
    reloadItems : function() {
      this.$allAtoms = this._getAtoms( this.element.children() );
    },
    
    // removes elements from Isotope widget
    remove : function( $content ) {

      this.$allAtoms = this.$allAtoms.not( $content );
      this.$filteredAtoms = this.$filteredAtoms.not( $content );

      $content.remove();
      
    },
    
    shuffle : function( callback ) {
      this.updateSortData( this.$allAtoms );
      this.options.sortBy = 'random';
      this._sort();
      this.reLayout( callback );
    },
    
    // destroys widget, returns elements and container back (close) to original style
    destroy : function() {

      var usingTransforms = this.usingTransforms;

      this.$allAtoms
        .removeClass( this.options.hiddenClass + ' ' + this.options.itemClass )
        .each(function(){
          this.style.position = '';
          this.style.top = '';
          this.style.left = '';
          this.style.opacity = '';
          if ( usingTransforms ) {
            this.style[ transformProp ] = '';
          }
        });
      
      // re-apply saved container styles
      var elemStyle = this.element[0].style;
      for ( var i=0, len = isoContainerStyles.length; i < len; i++ ) {
        var prop = isoContainerStyles[i];
        elemStyle[ prop ] = this.originalStyle[ prop ];
      }
      
      this.element
        .unbind('.isotope')
        .undelegate( '.' + this.options.hiddenClass, 'click' )
        .removeClass( this.options.containerClass )
        .removeData('isotope');
      
      $(window).unbind('.isotope');

    },
    
    
    // ====================== LAYOUTS ======================
    
    // calculates number of rows or columns
    // requires columnWidth or rowHeight to be set on namespaced object
    // i.e. this.masonry.columnWidth = 200
    _getSegments : function( isRows ) {
      var namespace = this.options.layoutMode,
          measure  = isRows ? 'rowHeight' : 'columnWidth',
          size     = isRows ? 'height' : 'width',
          segmentsName = isRows ? 'rows' : 'cols',
          containerSize = this.element[ size ](),
          segments,
                    // i.e. options.masonry && options.masonry.columnWidth
          segmentSize = this.options[ namespace ] && this.options[ namespace ][ measure ] ||
                    // or use the size of the first item, i.e. outerWidth
                    this.$filteredAtoms[ 'outer' + capitalize(size) ](true) ||
                    // if there's no items, use size of container
                    containerSize;
      
      segments = Math.floor( containerSize / segmentSize );
      segments = Math.max( segments, 1 );

      // i.e. this.masonry.cols = ....
      this[ namespace ][ segmentsName ] = segments;
      // i.e. this.masonry.columnWidth = ...
      this[ namespace ][ measure ] = segmentSize;
      
    },
    
    _checkIfSegmentsChanged : function( isRows ) {
      var namespace = this.options.layoutMode,
          segmentsName = isRows ? 'rows' : 'cols',
          prevSegments = this[ namespace ][ segmentsName ];
      // update cols/rows
      this._getSegments( isRows );
      // return if updated cols/rows is not equal to previous
      return ( this[ namespace ][ segmentsName ] !== prevSegments );
    },

    // ====================== Masonry ======================
  
    _masonryReset : function() {
      // layout-specific props
      this.masonry = {};
      // FIXME shouldn't have to call this again
      this._getSegments();
      var i = this.masonry.cols;
      this.masonry.colYs = [];
      while (i--) {
        this.masonry.colYs.push( 0 );
      }
    },
  
    _masonryLayout : function( $elems ) {
      var instance = this,
          props = instance.masonry;
      $elems.each(function(){
        var $this  = $(this),
            //how many columns does this brick span
            colSpan = Math.ceil( $this.outerWidth(true) / props.columnWidth );
        colSpan = Math.min( colSpan, props.cols );

        if ( colSpan === 1 ) {
          // if brick spans only one column, just like singleMode
          instance._masonryPlaceBrick( $this, props.colYs );
        } else {
          // brick spans more than one column
          // how many different places could this brick fit horizontally
          var groupCount = props.cols + 1 - colSpan,
              groupY = [],
              groupColY,
              i;

          // for each group potential horizontal position
          for ( i=0; i < groupCount; i++ ) {
            // make an array of colY values for that one group
            groupColY = props.colYs.slice( i, i+colSpan );
            // and get the max value of the array
            groupY[i] = Math.max.apply( Math, groupColY );
          }
        
          instance._masonryPlaceBrick( $this, groupY );
        }
      });
    },
    
    // worker method that places brick in the columnSet
    //   with the the minY
    _masonryPlaceBrick : function( $brick, setY ) {
      // get the minimum Y value from the columns
      var minimumY = Math.min.apply( Math, setY ),
          shortCol = 0;

      // Find index of short column, the first from the left
      for (var i=0, len = setY.length; i < len; i++) {
        if ( setY[i] === minimumY ) {
          shortCol = i;
          break;
        }
      }
    
      // position the brick
      var x = this.masonry.columnWidth * shortCol,
          y = minimumY;
      this._pushPosition( $brick, x, y );

      // apply setHeight to necessary columns
      var setHeight = minimumY + $brick.outerHeight(true),
          setSpan = this.masonry.cols + 1 - len;
      for ( i=0; i < setSpan; i++ ) {
        this.masonry.colYs[ shortCol + i ] = setHeight;
      }

    },
    
    _masonryGetContainerSize : function() {
      var containerHeight = Math.max.apply( Math, this.masonry.colYs );
      return { height: containerHeight };
    },
  
    _masonryResizeChanged : function() {
      return this._checkIfSegmentsChanged();
    },
  
    // ====================== fitRows ======================
    
    _fitRowsReset : function() {
      this.fitRows = {
        x : 0,
        y : 0,
        height : 0
      };
    },
  
    _fitRowsLayout : function( $elems ) {
      var instance = this,
          containerWidth = this.element.width(),
          props = this.fitRows;
      
      $elems.each( function() {
        var $this = $(this),
            atomW = $this.outerWidth(true),
            atomH = $this.outerHeight(true);
      
        if ( props.x !== 0 && atomW + props.x > containerWidth ) {
          // if this element cannot fit in the current row
          props.x = 0;
          props.y = props.height;
        } 
      
        // position the atom
        instance._pushPosition( $this, props.x, props.y );
  
        props.height = Math.max( props.y + atomH, props.height );
        props.x += atomW;
  
      });
    },
  
    _fitRowsGetContainerSize : function () {
      return { height : this.fitRows.height };
    },
  
    _fitRowsResizeChanged : function() {
      return true;
    },
  

    // ====================== cellsByRow ======================
  
    _cellsByRowReset : function() {
      this.cellsByRow = {
        index : 0
      };
      // get this.cellsByRow.columnWidth
      this._getSegments();
      // get this.cellsByRow.rowHeight
      this._getSegments(true);
    },

    _cellsByRowLayout : function( $elems ) {
      var instance = this,
          props = this.cellsByRow;
      $elems.each( function(){
        var $this = $(this),
            col = props.index % props.cols,
            row = Math.floor( props.index / props.cols ),
            x = Math.round( ( col + 0.5 ) * props.columnWidth - $this.outerWidth(true) / 2 ),
            y = Math.round( ( row + 0.5 ) * props.rowHeight - $this.outerHeight(true) / 2 );
        instance._pushPosition( $this, x, y );
        props.index ++;
      });
    },

    _cellsByRowGetContainerSize : function() {
      return { height : Math.ceil( this.$filteredAtoms.length / this.cellsByRow.cols ) * this.cellsByRow.rowHeight + this.offset.top };
    },

    _cellsByRowResizeChanged : function() {
      return this._checkIfSegmentsChanged();
    },
  
  
    // ====================== straightDown ======================
  
    _straightDownReset : function() {
      this.straightDown = {
        y : 0
      };
    },

    _straightDownLayout : function( $elems ) {
      var instance = this;
      $elems.each( function( i ){
        var $this = $(this);
        instance._pushPosition( $this, 0, instance.straightDown.y );
        instance.straightDown.y += $this.outerHeight(true);
      });
    },

    _straightDownGetContainerSize : function() {
      return { height : this.straightDown.y };
    },

    _straightDownResizeChanged : function() {
      return true;
    },


    // ====================== masonryHorizontal ======================
    
    _masonryHorizontalReset : function() {
      // layout-specific props
      this.masonryHorizontal = {};
      // FIXME shouldn't have to call this again
      this._getSegments( true );
      var i = this.masonryHorizontal.rows;
      this.masonryHorizontal.rowXs = [];
      while (i--) {
        this.masonryHorizontal.rowXs.push( 0 );
      }
    },
  
    _masonryHorizontalLayout : function( $elems ) {
      var instance = this,
          props = instance.masonryHorizontal;
      $elems.each(function(){
        var $this  = $(this),
            //how many rows does this brick span
            rowSpan = Math.ceil( $this.outerHeight(true) / props.rowHeight );
        rowSpan = Math.min( rowSpan, props.rows );

        if ( rowSpan === 1 ) {
          // if brick spans only one column, just like singleMode
          instance._masonryHorizontalPlaceBrick( $this, props.rowXs );
        } else {
          // brick spans more than one row
          // how many different places could this brick fit horizontally
          var groupCount = props.rows + 1 - rowSpan,
              groupX = [],
              groupRowX, i;

          // for each group potential horizontal position
          for ( i=0; i < groupCount; i++ ) {
            // make an array of colY values for that one group
            groupRowX = props.rowXs.slice( i, i+rowSpan );
            // and get the max value of the array
            groupX[i] = Math.max.apply( Math, groupRowX );
          }

          instance._masonryHorizontalPlaceBrick( $this, groupX );
        }
      });
    },
    
    _masonryHorizontalPlaceBrick : function( $brick, setX ) {
      // get the minimum Y value from the columns
      var minimumX  = Math.min.apply( Math, setX ),
          smallRow  = 0;
      // Find index of smallest row, the first from the top
      for (var i=0, len = setX.length; i < len; i++) {
        if ( setX[i] === minimumX ) {
          smallRow = i;
          break;
        }
      }

      // position the brick
      var x = minimumX,
          y = this.masonryHorizontal.rowHeight * smallRow;
      this._pushPosition( $brick, x, y );

      // apply setHeight to necessary columns
      var setWidth = minimumX + $brick.outerWidth(true),
          setSpan = this.masonryHorizontal.rows + 1 - len;
      for ( i=0; i < setSpan; i++ ) {
        this.masonryHorizontal.rowXs[ smallRow + i ] = setWidth;
      }
    },

    _masonryHorizontalGetContainerSize : function() {
      var containerWidth = Math.max.apply( Math, this.masonryHorizontal.rowXs );
      return { width: containerWidth };
    },
    
    _masonryHorizontalResizeChanged : function() {
      return this._checkIfSegmentsChanged(true);
    },


    // ====================== fitColumns ======================
  
    _fitColumnsReset : function() {
      this.fitColumns = {
        x : 0,
        y : 0,
        width : 0
      };
    },
    
    _fitColumnsLayout : function( $elems ) {
      var instance = this,
          containerHeight = this.element.height(),
          props = this.fitColumns;
      $elems.each( function() {
        var $this = $(this),
            atomW = $this.outerWidth(true),
            atomH = $this.outerHeight(true);

        if ( props.y !== 0 && atomH + props.y > containerHeight ) {
          // if this element cannot fit in the current column
          props.x = props.width;
          props.y = 0;
        } 

        // position the atom
        instance._pushPosition( $this, props.x, props.y );

        props.width = Math.max( props.x + atomW, props.width );
        props.y += atomH;

      });
    },
    
    _fitColumnsGetContainerSize : function () {
      return { width : this.fitColumns.width };
    },
    
    _fitColumnsResizeChanged : function() {
      return true;
    },
    

  
    // ====================== cellsByColumn ======================
  
    _cellsByColumnReset : function() {
      this.cellsByColumn = {
        index : 0
      };
      // get this.cellsByColumn.columnWidth
      this._getSegments();
      // get this.cellsByColumn.rowHeight
      this._getSegments(true);
    },

    _cellsByColumnLayout : function( $elems ) {
      var instance = this,
          props = this.cellsByColumn;
      $elems.each( function(){
        var $this = $(this),
            col = Math.floor( props.index / props.rows ),
            row = props.index % props.rows,
            x = Math.round( ( col + 0.5 ) * props.columnWidth - $this.outerWidth(true) / 2 ),
            y = Math.round( ( row + 0.5 ) * props.rowHeight - $this.outerHeight(true) / 2 );
        instance._pushPosition( $this, x, y );
        props.index ++;
      });
    },

    _cellsByColumnGetContainerSize : function() {
      return { width : Math.ceil( this.$filteredAtoms.length / this.cellsByColumn.rows ) * this.cellsByColumn.columnWidth };
    },

    _cellsByColumnResizeChanged : function() {
      return this._checkIfSegmentsChanged(true);
    },
    
    // ====================== straightAcross ======================

    _straightAcrossReset : function() {
      this.straightAcross = {
        x : 0
      };
    },

    _straightAcrossLayout : function( $elems ) {
      var instance = this;
      $elems.each( function( i ){
        var $this = $(this);
        instance._pushPosition( $this, instance.straightAcross.x, 0 );
        instance.straightAcross.x += $this.outerWidth(true);
      });
    },

    _straightAcrossGetContainerSize : function() {
      return { width : this.straightAcross.x };
    },

    _straightAcrossResizeChanged : function() {
      return true;
    }

  };
  
  
  // ======================= imagesLoaded Plugin ===============================
  /*!
   * jQuery imagesLoaded plugin v1.0.3
   * http://github.com/desandro/imagesloaded
   *
   * MIT License. by Paul Irish et al.
   */


  // $('#my-container').imagesLoaded(myFunction)
  // or
  // $('img').imagesLoaded(myFunction)

  // execute a callback when all images have loaded.
  // needed because .load() doesn't work on cached images

  // callback function gets image collection as argument
  //  `this` is the container

  $.fn.imagesLoaded = function( callback ) {
    var $this = this,
        $images = $this.find('img').add( $this.filter('img') ),
        len = $images.length,
        blank = 'data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///ywAAAAAAQABAAACAUwAOw==';

    function triggerCallback() {
      callback.call( $this, $images );
    }

    function imgLoaded( event ) {
      if ( --len <= 0 && event.target.src !== blank ){
        setTimeout( triggerCallback );
        $images.unbind( 'load error', imgLoaded );
      }
    }

    if ( !len ) {
      triggerCallback();
    }

    $images.bind( 'load error',  imgLoaded ).each( function() {
      // cached images don't fire load sometimes, so we reset src.
      if (this.complete || this.complete === undefined){
        var src = this.src;
        // webkit hack from http://groups.google.com/group/jquery-dev/browse_thread/thread/eee6ab7b2da50e1f
        // data uri bypasses webkit log warning (thx doug jones)
        this.src = blank;
        this.src = src;
      }
    });

    return $this;
  };


  // helper function for logging errors
  // $.error breaks jQuery chaining
  var logError = function( message ) {
    if ( window.console ) {
      window.console.error( message );
    }
  };

  // =======================  Plugin bridge  ===============================
  // leverages data method to either create or return $.Isotope constructor
  // A bit from jQuery UI
  //   https://github.com/jquery/jquery-ui/blob/master/ui/jquery.ui.widget.js
  // A bit from jcarousel 
  //   https://github.com/jsor/jcarousel/blob/master/lib/jquery.jcarousel.js

  $.fn.isotope = function( options, callback ) {
    if ( typeof options === 'string' ) {
      // call method
      var args = Array.prototype.slice.call( arguments, 1 );

      this.each(function(){
        var instance = $.data( this, 'isotope' );
        if ( !instance ) {
          logError( "cannot call methods on isotope prior to initialization; " +
              "attempted to call method '" + options + "'" );
          return;
        }
        if ( !$.isFunction( instance[options] ) || options.charAt(0) === "_" ) {
          logError( "no such method '" + options + "' for isotope instance" );
          return;
        }
        // apply method
        instance[ options ].apply( instance, args );
      });
    } else {
      this.each(function() {
        var instance = $.data( this, 'isotope' );
        if ( instance ) {
          // apply options & init
          instance.option( options );
          instance._init( callback );
        } else {
          // initialize new instance
          $.data( this, 'isotope', new $.Isotope( options, this, callback ) );
        }
      });
    }
    // return jQuery object
    // so plugin methods do not have to
    return this;
  };

})( window, jQuery );