item.js

/**
 * Outlayer Item
 */

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

}( window, function factory( EvEmitter, getSize ) {
'use strict';

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

function isEmptyObj( obj ) {
  for ( var prop in obj ) {
    return false;
  }
  prop = null;
  return true;
}

// -------------------------- CSS3 support -------------------------- //


var docElemStyle = document.documentElement.style;

var transitionProperty = typeof docElemStyle.transition == 'string' ?
  'transition' : 'WebkitTransition';
var transformProperty = typeof docElemStyle.transform == 'string' ?
  'transform' : 'WebkitTransform';

var transitionEndEvent = {
  WebkitTransition: 'webkitTransitionEnd',
  transition: 'transitionend'
}[ transitionProperty ];

// cache all vendor properties that could have vendor prefix
var vendorProperties = {
  transform: transformProperty,
  transition: transitionProperty,
  transitionDuration: transitionProperty + 'Duration',
  transitionProperty: transitionProperty + 'Property'
};

// -------------------------- Item -------------------------- //

function Item( element, layout ) {
  if ( !element ) {
    return;
  }

  this.element = element;
  // parent layout class, i.e. Masonry, Isotope, or Packery
  this.layout = layout;
  this.position = {
    x: 0,
    y: 0
  };

  this._create();
}

// inherit EvEmitter
var proto = Item.prototype = Object.create( EvEmitter.prototype );
proto.constructor = Item;

proto._create = function() {
  // transition objects
  this._transn = {
    ingProperties: {},
    clean: {},
    onEnd: {}
  };

  this.css({
    position: 'absolute'
  });
};

// trigger specified handler for event type
proto.handleEvent = function( event ) {
  var method = 'on' + event.type;
  if ( this[ method ] ) {
    this[ method ]( event );
  }
};

proto.getSize = function() {
  this.size = getSize( this.element );
};

/**
 * apply CSS styles to element
 * @param {Object} style
 */
proto.css = function( style ) {
  var elemStyle = this.element.style;

  for ( var prop in style ) {
    // use vendor property if available
    var supportedProp = vendorProperties[ prop ] || prop;
    elemStyle[ supportedProp ] = style[ prop ];
  }
};

 // measure position, and sets it
proto.getPosition = function() {
  var style = getComputedStyle( this.element );
  var isOriginLeft = this.layout._getOption('originLeft');
  var isOriginTop = this.layout._getOption('originTop');
  var xValue = style[ isOriginLeft ? 'left' : 'right' ];
  var yValue = style[ isOriginTop ? 'top' : 'bottom' ];
  // convert percent to pixels
  var layoutSize = this.layout.size;
  var x = xValue.indexOf('%') != -1 ?
    ( parseFloat( xValue ) / 100 ) * layoutSize.width : parseInt( xValue, 10 );
  var y = yValue.indexOf('%') != -1 ?
    ( parseFloat( yValue ) / 100 ) * layoutSize.height : parseInt( yValue, 10 );

  // clean up 'auto' or other non-integer values
  x = isNaN( x ) ? 0 : x;
  y = isNaN( y ) ? 0 : y;
  // remove padding from measurement
  x -= isOriginLeft ? layoutSize.paddingLeft : layoutSize.paddingRight;
  y -= isOriginTop ? layoutSize.paddingTop : layoutSize.paddingBottom;

  this.position.x = x;
  this.position.y = y;
};

// set settled position, apply padding
proto.layoutPosition = function() {
  var layoutSize = this.layout.size;
  var style = {};
  var isOriginLeft = this.layout._getOption('originLeft');
  var isOriginTop = this.layout._getOption('originTop');

  // x
  var xPadding = isOriginLeft ? 'paddingLeft' : 'paddingRight';
  var xProperty = isOriginLeft ? 'left' : 'right';
  var xResetProperty = isOriginLeft ? 'right' : 'left';

  var x = this.position.x + layoutSize[ xPadding ];
  // set in percentage or pixels
  style[ xProperty ] = this.getXValue( x );
  // reset other property
  style[ xResetProperty ] = '';

  // y
  var yPadding = isOriginTop ? 'paddingTop' : 'paddingBottom';
  var yProperty = isOriginTop ? 'top' : 'bottom';
  var yResetProperty = isOriginTop ? 'bottom' : 'top';

  var y = this.position.y + layoutSize[ yPadding ];
  // set in percentage or pixels
  style[ yProperty ] = this.getYValue( y );
  // reset other property
  style[ yResetProperty ] = '';

  this.css( style );
  this.emitEvent( 'layout', [ this ] );
};

proto.getXValue = function( x ) {
  var isHorizontal = this.layout._getOption('horizontal');
  return this.layout.options.percentPosition && !isHorizontal ?
    ( ( x / this.layout.size.width ) * 100 ) + '%' : x + 'px';
};

proto.getYValue = function( y ) {
  var isHorizontal = this.layout._getOption('horizontal');
  return this.layout.options.percentPosition && isHorizontal ?
    ( ( y / this.layout.size.height ) * 100 ) + '%' : y + 'px';
};

proto._transitionTo = function( x, y ) {
  this.getPosition();
  // get current x & y from top/left
  var curX = this.position.x;
  var curY = this.position.y;

  var compareX = parseInt( x, 10 );
  var compareY = parseInt( y, 10 );
  var didNotMove = compareX === this.position.x && compareY === this.position.y;

  // save end position
  this.setPosition( x, y );

  // if did not move and not transitioning, just go to layout
  if ( didNotMove && !this.isTransitioning ) {
    this.layoutPosition();
    return;
  }

  var transX = x - curX;
  var transY = y - curY;
  var transitionStyle = {};
  transitionStyle.transform = this.getTranslate( transX, transY );

  this.transition({
    to: transitionStyle,
    onTransitionEnd: {
      transform: this.layoutPosition
    },
    isCleaning: true
  });
};

proto.getTranslate = function( x, y ) {
  // flip cooridinates if origin on right or bottom
  var isOriginLeft = this.layout._getOption('originLeft');
  var isOriginTop = this.layout._getOption('originTop');
  x = isOriginLeft ? x : -x;
  y = isOriginTop ? y : -y;
  return 'translate3d(' + x + 'px, ' + y + 'px, 0)';
};

// non transition + transform support
proto.goTo = function( x, y ) {
  this.setPosition( x, y );
  this.layoutPosition();
};

proto.moveTo = proto._transitionTo;

proto.setPosition = function( x, y ) {
  this.position.x = parseInt( x, 10 );
  this.position.y = parseInt( y, 10 );
};

// ----- transition ----- //

/**
 * @param {Object} style - CSS
 * @param {Function} onTransitionEnd
 */

// non transition, just trigger callback
proto._nonTransition = function( args ) {
  this.css( args.to );
  if ( args.isCleaning ) {
    this._removeStyles( args.to );
  }
  for ( var prop in args.onTransitionEnd ) {
    args.onTransitionEnd[ prop ].call( this );
  }
};

/**
 * proper transition
 * @param {Object} args - arguments
 *   @param {Object} to - style to transition to
 *   @param {Object} from - style to start transition from
 *   @param {Boolean} isCleaning - removes transition styles after transition
 *   @param {Function} onTransitionEnd - callback
 */
proto.transition = function( args ) {
  // redirect to nonTransition if no transition duration
  if ( !parseFloat( this.layout.options.transitionDuration ) ) {
    this._nonTransition( args );
    return;
  }

  var _transition = this._transn;
  // keep track of onTransitionEnd callback by css property
  for ( var prop in args.onTransitionEnd ) {
    _transition.onEnd[ prop ] = args.onTransitionEnd[ prop ];
  }
  // keep track of properties that are transitioning
  for ( prop in args.to ) {
    _transition.ingProperties[ prop ] = true;
    // keep track of properties to clean up when transition is done
    if ( args.isCleaning ) {
      _transition.clean[ prop ] = true;
    }
  }

  // set from styles
  if ( args.from ) {
    this.css( args.from );
    // force redraw. http://blog.alexmaccaw.com/css-transitions
    var h = this.element.offsetHeight;
    // hack for JSHint to hush about unused var
    h = null;
  }
  // enable transition
  this.enableTransition( args.to );
  // set styles that are transitioning
  this.css( args.to );

  this.isTransitioning = true;

};

// dash before all cap letters, including first for
// WebkitTransform => -webkit-transform
function toDashedAll( str ) {
  return str.replace( /([A-Z])/g, function( $1 ) {
    return '-' + $1.toLowerCase();
  });
}

var transitionProps = 'opacity,' + toDashedAll( transformProperty );

proto.enableTransition = function(/* style */) {
  // HACK changing transitionProperty during a transition
  // will cause transition to jump
  if ( this.isTransitioning ) {
    return;
  }

  // make `transition: foo, bar, baz` from style object
  // HACK un-comment this when enableTransition can work
  // while a transition is happening
  // var transitionValues = [];
  // for ( var prop in style ) {
  //   // dash-ify camelCased properties like WebkitTransition
  //   prop = vendorProperties[ prop ] || prop;
  //   transitionValues.push( toDashedAll( prop ) );
  // }
  // enable transition styles
  this.css({
    transitionProperty: transitionProps,
    transitionDuration: this.layout.options.transitionDuration
  });
  // listen for transition end event
  this.element.addEventListener( transitionEndEvent, this, false );
};

// ----- events ----- //

proto.onwebkitTransitionEnd = function( event ) {
  this.ontransitionend( event );
};

proto.onotransitionend = function( event ) {
  this.ontransitionend( event );
};

// properties that I munge to make my life easier
var dashedVendorProperties = {
  '-webkit-transform': 'transform'
};

proto.ontransitionend = function( event ) {
  // disregard bubbled events from children
  if ( event.target !== this.element ) {
    return;
  }
  var _transition = this._transn;
  // get property name of transitioned property, convert to prefix-free
  var propertyName = dashedVendorProperties[ event.propertyName ] || event.propertyName;

  // remove property that has completed transitioning
  delete _transition.ingProperties[ propertyName ];
  // check if any properties are still transitioning
  if ( isEmptyObj( _transition.ingProperties ) ) {
    // all properties have completed transitioning
    this.disableTransition();
  }
  // clean style
  if ( propertyName in _transition.clean ) {
    // clean up style
    this.element.style[ event.propertyName ] = '';
    delete _transition.clean[ propertyName ];
  }
  // trigger onTransitionEnd callback
  if ( propertyName in _transition.onEnd ) {
    var onTransitionEnd = _transition.onEnd[ propertyName ];
    onTransitionEnd.call( this );
    delete _transition.onEnd[ propertyName ];
  }

  this.emitEvent( 'transitionEnd', [ this ] );
};

proto.disableTransition = function() {
  this.removeTransitionStyles();
  this.element.removeEventListener( transitionEndEvent, this, false );
  this.isTransitioning = false;
};

/**
 * removes style property from element
 * @param {Object} style
**/
proto._removeStyles = function( style ) {
  // clean up transition styles
  var cleanStyle = {};
  for ( var prop in style ) {
    cleanStyle[ prop ] = '';
  }
  this.css( cleanStyle );
};

var cleanTransitionStyle = {
  transitionProperty: '',
  transitionDuration: ''
};

proto.removeTransitionStyles = function() {
  // remove transition
  this.css( cleanTransitionStyle );
};

// ----- show/hide/remove ----- //

// remove element from DOM
proto.removeElem = function() {
  this.element.parentNode.removeChild( this.element );
  // remove display: none
  this.css({ display: '' });
  this.emitEvent( 'remove', [ this ] );
};

proto.remove = function() {
  // just remove element if no transition support or no transition
  if ( !transitionProperty || !parseFloat( this.layout.options.transitionDuration ) ) {
    this.removeElem();
    return;
  }

  // start transition
  this.once( 'transitionEnd', function() {
    this.removeElem();
  });
  this.hide();
};

proto.reveal = function() {
  delete this.isHidden;
  // remove display: none
  this.css({ display: '' });

  var options = this.layout.options;

  var onTransitionEnd = {};
  var transitionEndProperty = this.getHideRevealTransitionEndProperty('visibleStyle');
  onTransitionEnd[ transitionEndProperty ] = this.onRevealTransitionEnd;

  this.transition({
    from: options.hiddenStyle,
    to: options.visibleStyle,
    isCleaning: true,
    onTransitionEnd: onTransitionEnd
  });
};

proto.onRevealTransitionEnd = function() {
  // check if still visible
  // during transition, item may have been hidden
  if ( !this.isHidden ) {
    this.emitEvent('reveal');
  }
};

/**
 * get style property use for hide/reveal transition end
 * @param {String} styleProperty - hiddenStyle/visibleStyle
 * @returns {String}
 */
proto.getHideRevealTransitionEndProperty = function( styleProperty ) {
  var optionStyle = this.layout.options[ styleProperty ];
  // use opacity
  if ( optionStyle.opacity ) {
    return 'opacity';
  }
  // get first property
  for ( var prop in optionStyle ) {
    return prop;
  }
};

proto.hide = function() {
  // set flag
  this.isHidden = true;
  // remove display: none
  this.css({ display: '' });

  var options = this.layout.options;

  var onTransitionEnd = {};
  var transitionEndProperty = this.getHideRevealTransitionEndProperty('hiddenStyle');
  onTransitionEnd[ transitionEndProperty ] = this.onHideTransitionEnd;

  this.transition({
    from: options.visibleStyle,
    to: options.hiddenStyle,
    // keep hidden stuff hidden
    isCleaning: true,
    onTransitionEnd: onTransitionEnd
  });
};

proto.onHideTransitionEnd = function() {
  // check if still hidden
  // during transition, item may have been un-hidden
  if ( this.isHidden ) {
    this.css({ display: 'none' });
    this.emitEvent('hide');
  }
};

proto.destroy = function() {
  this.css({
    position: '',
    left: '',
    right: '',
    top: '',
    bottom: '',
    transition: '',
    transform: ''
  });
};

return Item;

}));