/** * elastiStack.js v1.0.0 * http://www.codrops.com * * Licensed under the MIT license. * http://www.opensource.org/licenses/mit-license.php * * Copyright 2015, Codrops * http://www.codrops.com */ ;( function( window ) { 'use strict'; function extend( a, b ) { for( var key in b ) { if( b.hasOwnProperty( key ) ) { a[key] = b[key]; } } return a; } // support var is3d = !!getStyleProperty( 'perspective' ), support = { transitions: Modernizr.csstransitions }, // transition end event name transEndEventNames = { 'WebkitTransition': 'webkitTransitionEnd', 'MozTransition': 'transitionend', 'OTransition': 'oTransitionEnd', 'msTransition': 'MSTransitionEnd', 'transition': 'transitionend' }, transEndEventName = transEndEventNames[ Modernizr.prefixed( 'transition' ) ], onEndTransition = function( el, callback ) { var onEndCallbackFn = function( ev ) { if( support.transitions ) { if( ev.target != this ) return; this.removeEventListener( transEndEventName, onEndCallbackFn ); } if( callback && typeof callback === 'function' ) { callback.call(this); } }; if( support.transitions ) { el.addEventListener( transEndEventName, onEndCallbackFn ); } else { onEndCallbackFn(); } }; function ElastiStack( el, options ) { this.container = el; this.options = extend( {}, this.options ); extend( this.options, options ); this._init(); } function setTransformStyle( el, tval ) { el.style.WebkitTransform = tval; el.style.msTransform = tval; el.style.transform = tval; } ElastiStack.prototype.options = { // distDragBack: if the user stops dragging the image in a area that does not exceed [distDragBack]px for either x or y then the image goes back to the stack distDragBack : 200, // distDragMax: if the user drags the image in a area that exceeds [distDragMax]px for either x or y then the image moves away from the stack distDragMax : 450, // callback onUpdateStack : function( current ) { return false; } }; ElastiStack.prototype._init = function() { // items this.items = [].slice.call( this.container.children ); // total items this.itemsCount = this.items.length; // current item's index (the one on the top of the stack) this.current = 0; // set initial styles this._setStackStyle(); // return if no items or only one if( this.itemsCount <= 1 ) return; // add dragging capability this._initDragg(); // init drag events this._initEvents(); }; ElastiStack.prototype._initEvents = function() { var self = this; this.draggie.on( 'dragStart', function( i, e, p ) { self._onDragStart( i, e, p ); } ); this.draggie.on( 'dragMove', function( i, e, p ) { self._onDragMove( i, e, p ); } ); this.draggie.on( 'dragEnd', function( i, e, p ) { self._onDragEnd( i, e, p ); } ); }; ElastiStack.prototype._setStackStyle = function() { var item1 = this._firstItem(), item2 = this._secondItem(), item3 = this._thirdItem(); if( item1 ) { item1.style.opacity = 1; item1.style.zIndex = 4; setTransformStyle( item1, is3d ? 'translate3d(0,0,0)' : 'translate(0,0)' ); } if( item2 ) { item2.style.opacity = 1; item2.style.zIndex = 3; setTransformStyle( item2, is3d ? 'translate3d(0,-18px, -75px)' : 'translate(0,0)' ); } if( item3 ) { item3.style.opacity = 1; item3.style.zIndex = 2; setTransformStyle( item3, is3d ? 'translate3d(0,-35px, -170px)' : 'translate(0,0)' ); } }; ElastiStack.prototype._reset = function() { // reorder stack this.current = this.current < this.itemsCount - 1 ? this.current + 1 : 0; // new front items var item1 = this._firstItem(), item2 = this._secondItem(), item3 = this._thirdItem(); // reset transition timing function classie.remove( item1, 'move-back' ); if( item2 ) classie.remove( item2, 'move-back' ); if( item3 ) classie.remove( item3, 'move-back' ); var self = this; setTimeout( function() { // the upcoming one will animate.. classie.add( self._lastItem(), 'animate' ); // reset styles self._setStackStyle(); }, 25 ); // add dragging capability this._initDragg(); // init drag events on new current item this._initEvents(); // callback this.options.onUpdateStack( this.current ); }; ElastiStack.prototype._moveAway = function( instance ) { var el = instance.element; // disable drag this._disableDragg(); // add class "animate" classie.add( el, 'animate' ); // calculate how much to translate in the x and y axis var tVal = this._getTranslateVal( instance ); // apply it setTransformStyle( el, is3d ? 'translate3d(' + tVal.x + 'px,' + tVal.y + 'px, 0px)' : 'translate(' + tVal.x + 'px,' + tVal.y + 'px)' ); // item also fades out el.style.opacity = 0; // other items move back to stack var item2 = this._secondItem(), item3 = this._thirdItem(); if( item2 ) { classie.add( item2, 'move-back' ); classie.add( item2, 'animate' ); setTransformStyle( item2, is3d ? 'translate3d(0,-18px, -75px)' : 'translate(0,0)' ); } if( item3 ) { classie.add( item3, 'move-back' ); classie.add( item3, 'animate' ); setTransformStyle( item3, is3d ? 'translate3d(0,-35px, -170px)' : 'translate(0,0)' ); } // after transition ends.. var self = this; onEndTransition( el, function() { // reset first item setTransformStyle( el, is3d ? 'translate3d(0,0,-180px)' : 'translate(0,0,0)' ); el.style.left = el.style.top = '0px'; el.style.zIndex = -1; classie.remove( el, 'animate' ); self._reset(); } ); }; ElastiStack.prototype._moveBack = function( instance ) { var item2 = this._secondItem(), item3 = this._thirdItem(); classie.add( instance.element, 'move-back' ); classie.add( instance.element, 'animate' ); setTransformStyle( instance.element, is3d ? 'translate3d(0,0,0)' : 'translate(0,0)' ); instance.element.style.left = '0px'; instance.element.style.top = '0px'; if( item2 ) { classie.add( item2, 'move-back' ); classie.add( item2, 'animate' ); setTransformStyle( item2, is3d ? 'translate3d(0,-18px, -75px)' : 'translate(0,0)' ); } if( item3 ) { classie.add( item3, 'move-back' ); classie.add( item3, 'animate' ); setTransformStyle( item3, is3d ? 'translate3d(0,-35px, -170px)' : 'translate(0,0)' ); } }; ElastiStack.prototype._onDragStart = function( instance, event, pointer ) { // remove transition classes if any var item2 = this._secondItem(), item3 = this._thirdItem(); classie.remove( instance.element, 'move-back' ); classie.remove( instance.element, 'animate' ); if( item2 ) { classie.remove( item2, 'move-back' ); classie.remove( item2, 'animate' ); } if( item3 ) { classie.remove( item3, 'move-back' ); classie.remove( item3, 'animate' ); } }; ElastiStack.prototype._onDragMove = function( instance, event, pointer ) { if( this._outOfBounds( instance ) ) { this._moveAway( instance ); } else { // the second and third items also move var item2 = this._secondItem(), item3 = this._thirdItem(); if( item2 ) { setTransformStyle( item2, is3d ? 'translate3d(' + ( instance.position.x * .6 ) + 'px,' + ( instance.position.y * .6 ) + 'px, -100px)' : 'translate(' + ( instance.position.x * .6 ) + 'px,' + ( instance.position.y * .6 ) + 'px)' ); } if( item3 ) { setTransformStyle( item3, is3d ? 'translate3d(' + ( instance.position.x * .3 ) + 'px,' + ( instance.position.y * .3 ) + 'px, -200px)' : 'translate(' + ( instance.position.x * .3 ) + 'px,' + ( instance.position.y * .3 ) + 'px)' ); } } }; ElastiStack.prototype._onDragEnd = function( instance, event, pointer ) { if( this._outOfBounds( instance ) ) return; if( this._outOfSight(instance) ) { this._moveAway( instance ); } else { this._moveBack( instance ); } }; ElastiStack.prototype._initDragg = function() { this.draggie = new Draggabilly( this.items[ this.current ] ); }; ElastiStack.prototype._disableDragg = function() { this.draggie.disable(); }; ElastiStack.prototype.nextItem = function( val ) { if( this.isAnimating ) { return false; } this.isAnimating = true; var item1 = this._firstItem(), item2 = this._secondItem(), item3 = this._thirdItem(); // first item get class animate classie.add( item1, 'animate' ); if( item2 ) { classie.add( item2, 'animate' ); } if( item3 ) { classie.add( item3, 'animate' ); } // now translate up and fade out (Z axis) setTransformStyle( item1, is3d ? val.transform : 'translate(0,0)' ); item1.style.opacity = 0; item1.style.zIndex = 5; var self = this; onEndTransition( item1, function() { classie.remove( item1, 'animate' ); //classie.remove( this, 'move-back' ); item1.style.zIndex = -1; // reset first item setTimeout( function() { setTransformStyle( item1, is3d ? 'translate3d(0,0,-180px)' : 'translate(0,0,0)' ); self.isAnimating = false; }, 25 ); } ); // disable drag this._disableDragg(); this._reset(); }; // returns true if x or y is bigger than distDragMax ElastiStack.prototype._outOfBounds = function( el ) { return Math.abs( el.position.x ) > this.options.distDragMax || Math.abs( el.position.y ) > this.options.distDragMax; }; // returns true if x or y is bigger than distDragBack ElastiStack.prototype._outOfSight = function( el ) { return Math.abs( el.position.x ) > this.options.distDragBack || Math.abs( el.position.y ) > this.options.distDragBack; }; ElastiStack.prototype._getTranslateVal = function( el ) { var h = Math.sqrt( Math.pow( el.position.x, 2 ) + Math.pow( el.position.y, 2 ) ), a = Math.asin( Math.abs( el.position.y ) / h ) / ( Math.PI / 180 ), hL = h + this.options.distDragBack, dx = Math.cos( a * ( Math.PI / 180 ) ) * hL, dy = Math.sin( a * ( Math.PI / 180 ) ) * hL, tx = dx - Math.abs( el.position.x ), ty = dy - Math.abs( el.position.y ); return { x : el.position.x > 0 ? tx : tx * -1, y : el.position.y > 0 ? ty : ty * -1 } }; // returns the first item in the stack ElastiStack.prototype._firstItem = function() { return this.items[ this.current ]; }; // returns the second item in the stack ElastiStack.prototype._secondItem = function() { if( this.itemsCount >= 2 ) { return this.current + 1 < this.itemsCount ? this.items[ this.current + 1 ] : this.items[ Math.abs( this.itemsCount - ( this.current + 1 ) ) ]; } }; // returns the third item in the stack ElastiStack.prototype._thirdItem = function() { if( this.itemsCount >= 3 ) { return this.current + 2 < this.itemsCount ? this.items[ this.current + 2 ] : this.items[ Math.abs( this.itemsCount - ( this.current + 2 ) ) ]; } }; // returns the last item (of the first three) in the stack ElastiStack.prototype._lastItem = function() { if( this.itemsCount >= 3 ) { return this._thirdItem(); } else { return this._secondItem(); } }; // add to global namespace window.ElastiStack = ElastiStack; })( window );