masonry.js

/*!
 * Masonry v3.1.2
 * Cascading grid layout library
 * http://masonry.desandro.com
 * MIT License
 * by David DeSandro
 */

( function( window ) {

'use strict';

// -------------------------- helpers -------------------------- //

var indexOf = Array.prototype.indexOf ?
  function( items, value ) {
    return items.indexOf( value );
  } :
  function ( items, value ) {
    for ( var i=0, len = items.length; i < len; i++ ) {
      var item = items[i];
      if ( item === value ) {
        return i;
      }
    }
    return -1;
  };

// -------------------------- masonryDefinition -------------------------- //

// used for AMD definition and requires
function masonryDefinition( Outlayer, getSize ) {
  // create an Outlayer layout class
  var Masonry = Outlayer.create('masonry');

  Masonry.prototype._resetLayout = function() {
    this.getSize();
    this._getMeasurement( 'columnWidth', 'outerWidth' );
    this._getMeasurement( 'gutter', 'outerWidth' );
    this.measureColumns();

    // reset column Y
    var i = this.cols;
    this.colYs = [];
    while (i--) {
      this.colYs.push( 0 );
    }

    this.maxY = 0;
  };

  Masonry.prototype.measureColumns = function() {
    this.getContainerWidth();
    // if columnWidth is 0, default to outerWidth of first item
    if ( !this.columnWidth ) {
      var firstItem = this.items[0];
      var firstItemElem = firstItem && firstItem.element;
      // columnWidth fall back to item of first element
      this.columnWidth = firstItemElem && getSize( firstItemElem ).outerWidth ||
        // if first elem has no width, default to size of container
        this.containerWidth;
    }

    this.columnWidth += this.gutter;

    this.cols = Math.floor( ( this.containerWidth + this.gutter ) / this.columnWidth );
    this.cols = Math.max( this.cols, 1 );
  };

  Masonry.prototype.getContainerWidth = function() {
    // container is parent if fit width
    var container = this.options.isFitWidth ? this.element.parentNode : this.element;
    // check that this.size and size are there
    // IE8 triggers resize on body size change, so they might not be
    var size = getSize( container );
    this.containerWidth = size && size.innerWidth;
  };

  Masonry.prototype._getItemLayoutPosition = function( item ) {
    item.getSize();
    // how many columns does this brick span
    var colSpan = Math.ceil( item.size.outerWidth / this.columnWidth );
    colSpan = Math.min( colSpan, this.cols );

    var colGroup = this._getColGroup( colSpan );
    // get the minimum Y value from the columns
    var minimumY = Math.min.apply( Math, colGroup );
    var shortColIndex = indexOf( colGroup, minimumY );

    // position the brick
    var position = {
      x: this.columnWidth * shortColIndex,
      y: minimumY
    };

    // apply setHeight to necessary columns
    var setHeight = minimumY + item.size.outerHeight;
    var setSpan = this.cols + 1 - colGroup.length;
    for ( var i = 0; i < setSpan; i++ ) {
      this.colYs[ shortColIndex + i ] = setHeight;
    }

    return position;
  };

  /**
   * @param {Number} colSpan - number of columns the element spans
   * @returns {Array} colGroup
   */
  Masonry.prototype._getColGroup = function( colSpan ) {
    if ( colSpan < 2 ) {
      // if brick spans only one column, use all the column Ys
      return this.colYs;
    }

    var colGroup = [];
    // how many different places could this brick fit horizontally
    var groupCount = this.cols + 1 - colSpan;
    // for each group potential horizontal position
    for ( var i = 0; i < groupCount; i++ ) {
      // make an array of colY values for that one group
      var groupColYs = this.colYs.slice( i, i + colSpan );
      // and get the max value of the array
      colGroup[i] = Math.max.apply( Math, groupColYs );
    }
    return colGroup;
  };

  Masonry.prototype._manageStamp = function( stamp ) {
    var stampSize = getSize( stamp );
    var offset = this._getElementOffset( stamp );
    // get the columns that this stamp affects
    var firstX = this.options.isOriginLeft ? offset.left : offset.right;
    var lastX = firstX + stampSize.outerWidth;
    var firstCol = Math.floor( firstX / this.columnWidth );
    firstCol = Math.max( 0, firstCol );
    var lastCol = Math.floor( lastX / this.columnWidth );
    lastCol = Math.min( this.cols - 1, lastCol );
    // set colYs to bottom of the stamp
    var stampMaxY = ( this.options.isOriginTop ? offset.top : offset.bottom ) +
      stampSize.outerHeight;
    for ( var i = firstCol; i <= lastCol; i++ ) {
      this.colYs[i] = Math.max( stampMaxY, this.colYs[i] );
    }
  };

  Masonry.prototype._getContainerSize = function() {
    this.maxY = Math.max.apply( Math, this.colYs );
    var size = {
      height: this.maxY
    };

    if ( this.options.isFitWidth ) {
      size.width = this._getContainerFitWidth();
    }

    return size;
  };

  Masonry.prototype._getContainerFitWidth = function() {
    var unusedCols = 0;
    // count unused columns
    var i = this.cols;
    while ( --i ) {
      if ( this.colYs[i] !== 0 ) {
        break;
      }
      unusedCols++;
    }
    // fit container to columns that have been used
    return ( this.cols - unusedCols ) * this.columnWidth - this.gutter;
  };

  // debounced, layout on resize
  // HEADS UP this overwrites Outlayer.resize
  // Any changes in Outlayer.resize need to be manually added here
  Masonry.prototype.resize = function() {
    // don't trigger if size did not change
    var previousWidth = this.containerWidth;
    this.getContainerWidth();
    if ( previousWidth === this.containerWidth ) {
      return;
    }

    this.layout();
  };

  return Masonry;
}

// -------------------------- transport -------------------------- //

if ( typeof define === 'function' && define.amd ) {
  // AMD
  define( [
      'outlayer/outlayer',
      'get-size/get-size'
    ],
    masonryDefinition );
} else {
  // browser global
  window.Masonry = masonryDefinition(
    window.Outlayer,
    window.getSize
  );
}

})( window );