masonry.js

/*!
 * Masonry v4.2.1
 * Cascading grid layout library
 * https://masonry.desandro.com
 * MIT License
 * by David DeSandro
 */

( function( window, factory ) {
  // universal module definition
  /* jshint strict: false */ /*globals define, module, require */
  if ( typeof define == 'function' && define.amd ) {
    // AMD
    define( [
        'outlayer/outlayer',
        'get-size/get-size'
      ],
      factory );
  } else if ( typeof module == 'object' && module.exports ) {
    // CommonJS
    module.exports = factory(
      require('outlayer'),
      require('get-size')
    );
  } else {
    // browser global
    window.Masonry = factory(
      window.Outlayer,
      window.getSize
    );
  }

}( window, function factory( Outlayer, getSize ) {

'use strict';

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

  // create an Outlayer layout class
  var Masonry = Outlayer.create('masonry');
  // isFitWidth -> fitWidth
  Masonry.compatOptions.fitWidth = 'isFitWidth';

  var proto = Masonry.prototype;

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

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

    this.maxY = 0;
    this.horizontalColIndex = 0;
  };

  proto.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;
    }

    var columnWidth = this.columnWidth += this.gutter;

    // calculate columns
    var containerWidth = this.containerWidth + this.gutter;
    var cols = containerWidth / columnWidth;
    // fix rounding errors, typically with gutters
    var excess = columnWidth - containerWidth % columnWidth;
    // if overshoot is less than a pixel, round up, otherwise floor it
    var mathMethod = excess && excess < 1 ? 'round' : 'floor';
    cols = Math[ mathMethod ]( cols );
    this.cols = Math.max( cols, 1 );
  };

  proto.getContainerWidth = function() {
    // container is parent if fit width
    var isFitWidth = this._getOption('fitWidth');
    var container = 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;
  };

  proto._getItemLayoutPosition = function( item ) {
    item.getSize();
    // how many columns does this brick span
    var remainder = item.size.outerWidth % this.columnWidth;
    var mathMethod = remainder && remainder < 1 ? 'round' : 'ceil';
    // round if off by 1 pixel, otherwise use ceil
    var colSpan = Math[ mathMethod ]( item.size.outerWidth / this.columnWidth );
    colSpan = Math.min( colSpan, this.cols );
    // use horizontal or top column position
    var colPosMethod = this.options.horizontalOrder ?
      '_getHorizontalColPosition' : '_getTopColPosition';
    var colPosition = this[ colPosMethod ]( colSpan, item );
    // position the brick
    var position = {
      x: this.columnWidth * colPosition.col,
      y: colPosition.y
    };
    // apply setHeight to necessary columns
    var setHeight = colPosition.y + item.size.outerHeight;
    var setMax = colSpan + colPosition.col;
    for ( var i = colPosition.col; i < setMax; i++ ) {
      this.colYs[i] = setHeight;
    }

    return position;
  };

  proto._getTopColPosition = function( colSpan ) {
    var colGroup = this._getTopColGroup( colSpan );
    // get the minimum Y value from the columns
    var minimumY = Math.min.apply( Math, colGroup );

    return {
      col: colGroup.indexOf( minimumY ),
      y: minimumY,
    };
  };

  /**
   * @param {Number} colSpan - number of columns the element spans
   * @returns {Array} colGroup
   */
  proto._getTopColGroup = 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++ ) {
      colGroup[i] = this._getColGroupY( i, colSpan );
    }
    return colGroup;
  };

  proto._getColGroupY = function( col, colSpan ) {
    if ( colSpan < 2 ) {
      return this.colYs[ col ];
    }
    // make an array of colY values for that one group
    var groupColYs = this.colYs.slice( col, col + colSpan );
    // and get the max value of the array
    return Math.max.apply( Math, groupColYs );
  };

  // get column position based on horizontal index. #873
  proto._getHorizontalColPosition = function( colSpan, item ) {
    var col = this.horizontalColIndex % this.cols;
    var isOver = colSpan > 1 && col + colSpan > this.cols;
    // shift to next row if item can't fit on current row
    col = isOver ? 0 : col;
    // don't let zero-size items take up space
    var hasSize = item.size.outerWidth && item.size.outerHeight;
    this.horizontalColIndex = hasSize ? col + colSpan : this.horizontalColIndex;

    return {
      col: col,
      y: this._getColGroupY( col, colSpan ),
    };
  };

  proto._manageStamp = function( stamp ) {
    var stampSize = getSize( stamp );
    var offset = this._getElementOffset( stamp );
    // get the columns that this stamp affects
    var isOriginLeft = this._getOption('originLeft');
    var firstX = 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 should not go over if multiple of columnWidth #425
    lastCol -= lastX % this.columnWidth ? 0 : 1;
    lastCol = Math.min( this.cols - 1, lastCol );
    // set colYs to bottom of the stamp

    var isOriginTop = this._getOption('originTop');
    var stampMaxY = ( isOriginTop ? offset.top : offset.bottom ) +
      stampSize.outerHeight;
    for ( var i = firstCol; i <= lastCol; i++ ) {
      this.colYs[i] = Math.max( stampMaxY, this.colYs[i] );
    }
  };

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

    if ( this._getOption('fitWidth') ) {
      size.width = this._getContainerFitWidth();
    }

    return size;
  };

  proto._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;
  };

  proto.needsResizeLayout = function() {
    var previousWidth = this.containerWidth;
    this.getContainerWidth();
    return previousWidth != this.containerWidth;
  };

  return Masonry;

}));