299 lines
9.4 KiB
JavaScript
299 lines
9.4 KiB
JavaScript
/*
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scrollorama - The jQuery plugin for doing cool scrolly stuff
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by John Polacek (@johnpolacek)
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Dual licensed under MIT and GPL.
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*/
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(function($) {
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$.scrollorama = function(options) {
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// PRIVATE VARS
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var blocks = [],
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browserPrefix = '',
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onBlockChange = function() {};
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var scrollorama = this;
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var defaults = {offset:0};
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scrollorama.settings = $.extend({}, defaults, options);
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scrollorama.blockIndex = 0;
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if (options.blocks === undefined) alert('ERROR: Must assign blocks class selector to scrollorama plugin');
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// PRIVATE FUNCTIONS
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function init() {
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if (typeof scrollorama.settings.blocks === 'string') scrollorama.settings.blocks = $(scrollorama.settings.blocks);
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// set browser prefix
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if ($.browser.mozilla) browserPrefix = '-moz-';
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if ($.browser.webkit) browserPrefix = '-webkit-';
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if ($.browser.opera) browserPrefix = '-o-';
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if ($.browser.msie) browserPrefix = '-ms-';
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// create blocks array to contain animation props
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$('body').css('position','relative');
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var i;
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for (i=0; i<scrollorama.settings.blocks.length; i++) {
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var block = scrollorama.settings.blocks.eq(i);
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blocks.push({
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block: block,
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top: block.offset().top,
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pin: 0,
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animations:[]
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});
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}
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// convert block elements to absolute position
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for (i=0; i<blocks.length; i++) {
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blocks[i].block
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.css('position', 'absolute')
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.css('top', blocks[i].top);
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}
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$("body").prepend("<div id='scroll-wrap'></div>");
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var didScroll = false;
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$(window).scroll(function(){
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didScroll = true;
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});
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setInterval(function(){
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if(didScroll){
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onScrollorama();
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didScroll = false;
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}
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}, 50);
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}
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function onScrollorama() {
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var scrollTop = $(window).scrollTop();
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var currBlockIndex = getCurrBlockIndex(scrollTop);
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// update all animations
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for (var i=0; i<blocks.length; i++) {
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// go through the animations for each block
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if (blocks[i].animations.length) {
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for (var j=0; j<blocks[i].animations.length; j++) {
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var anim = blocks[i].animations[j];
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// if above current block, settings should be at start value
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if (i > currBlockIndex) {
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if (currBlockIndex != i-1 && anim.baseline != 'bottom') {
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setProperty(anim.element, anim.property, anim.startVal);
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}
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if (blocks[i].pin) {
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blocks[i].block
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.css('position', 'absolute')
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.css('top', blocks[i].top);
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}
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}
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// if below current block, settings should be at end value
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// unless on an element that gets animated when it hits the bottom of the viewport
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else if (i < currBlockIndex) {
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setProperty(anim.element, anim.property, anim.endVal);
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if (blocks[i].pin) {
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blocks[i].block
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.css('position', 'absolute')
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.css('top', (blocks[i].top + blocks[i].pin));
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}
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}
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// otherwise, set values per scroll position
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if (i == currBlockIndex || (currBlockIndex == i-1 && anim.baseline == 'bottom')) {
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// if block gets pinned, set position fixed
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if (blocks[i].pin && currBlockIndex == i) {
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blocks[i].block
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.css('position', 'fixed')
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.css('top', 0);
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}
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// set start and end animation positions
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var startAnimPos = blocks[i].top + anim.delay;
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if (anim.baseline == 'bottom') startAnimPos -= $(window).height();
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var endAnimPos = startAnimPos + anim.duration;
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// if scroll is before start of animation, set to start value
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if (scrollTop < startAnimPos) setProperty(anim.element, anim.property, anim.startVal);
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// if scroll is after end of animation, set to end value
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else if (scrollTop > endAnimPos) {
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setProperty(anim.element, anim.property, anim.endVal);
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if (blocks[i].pin) {
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blocks[i].block
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.css('position', 'absolute')
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.css('top', (blocks[i].top + blocks[i].pin));
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}
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}
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// otherwise, set value based on scroll
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else {
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// calculate percent to animate
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var animPercent = (scrollTop - startAnimPos) / anim.duration;
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// then multiply the percent by the value range and calculate the new value
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var animVal = anim.startVal + (animPercent * (anim.endVal - anim.startVal));
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setProperty(anim.element, anim.property, animVal);
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}
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}
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}
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}
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}
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// update blockIndex and trigger event if changed
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if (scrollorama.blockIndex != currBlockIndex) {
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scrollorama.blockIndex = currBlockIndex;
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onBlockChange();
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}
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}
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function getCurrBlockIndex(scrollTop) {
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var currBlockIndex = 0;
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for (var i=0; i<blocks.length; i++) {
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// check if block is in view
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if (blocks[i].top <= scrollTop - scrollorama.settings.offset) currBlockIndex = i;
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}
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return currBlockIndex;
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}
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function setProperty(target, prop, val) {
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if (prop === 'rotate' || prop === 'zoom' || prop === 'scale') {
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if (prop === 'rotate') {
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target.css(browserPrefix+'transform', 'rotate('+val+'deg)');
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} else if (prop === 'zoom' || prop === 'scale') {
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var scaleCSS = 'scale('+val+')';
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if (browserPrefix !== '-ms-') {
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target.css(browserPrefix+'transform', scaleCSS);
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} else {
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target.css('zoom', scaleCSS);
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}
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}
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} else {
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target.css(prop, val);
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}
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}
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// PUBLIC FUNCTIONS
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scrollorama.animate = function(target) {
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/*
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target = animation target
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arguments = array of animation parameters
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animation parameters:
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delay = amount of scrolling (in pixels) before animation starts
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duration = amount of scrolling (in pixels) over which the animation occurs
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property = css property being animated
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start = start value of the property
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end = end value of the property
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pin = pin block during animation duration (applies to all animations within block)
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baseline = top (default, when block reaches top of viewport) or bottom (when block first comies into view)
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*/
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// if string, convert to DOM object
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if (typeof target === 'string') target = $(target);
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// find block of target
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var targetIndex;
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var targetBlock;
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for (var i=0; i<blocks.length; i++) {
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if (blocks[i].block.has(target).length) {
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targetBlock = blocks[i];
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targetIndex = i;
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}
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}
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// add each animation to the blocks animations array
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for (i=1; i<arguments.length; i++) {
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var anim = arguments[i];
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// for top/left/right/bottom, set relative positioning if static
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if (anim.property == 'top' || anim.property == 'left' || anim.property == 'bottom' || anim.property == 'right' ) {
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if (target.css('position') == 'static') target.css('position','relative');
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// set anim.start, anim.end defaults
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if (anim.start === undefined) anim.start = 0;
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else if (anim.end === undefined) anim.end = 0;
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}
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// set anim.start/anim.end defaults for rotate, zoom/scale, letter-spacing
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if (anim.property == 'rotate') {
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if (anim.start === undefined) anim.start = 0;
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if (anim.end === undefined) anim.end = 0;
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} else if (anim.property == 'zoom' || anim.property == 'scale' ) {
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if (anim.start === undefined) anim.start = 1;
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if (anim.end === undefined) anim.end = 1;
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} else if (anim.property == 'letter-spacing' && target.css(anim.property)) {
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if (anim.start === undefined) anim.start = 1;
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if (anim.end === undefined) anim.end = 1;
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}
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if (anim.baseline === undefined) {
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if (anim.pin || targetBlock.pin || targetIndex === 0) anim.baseline = 'top';
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else anim.baseline = 'bottom';
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}
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if (anim.delay === undefined) anim.delay = 0;
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targetBlock.animations.push({
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element: target,
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delay: anim.delay,
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duration: anim.duration,
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property: anim.property,
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startVal: anim.start !== undefined ? anim.start : parseInt(target.css(anim.property),10), // if undefined, use current css value
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endVal: anim.end !== undefined ? anim.end : parseInt(target.css(anim.property),10), // if undefined, use current css value
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baseline: anim.baseline !== undefined ? anim.baseline : 'bottom'
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});
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if (anim.pin) {
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if (targetBlock.pin < anim.duration + anim.delay) {
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var offset = anim.duration + anim.delay - targetBlock.pin;
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targetBlock.pin += offset;
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// adjust positions of blocks below target block
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for (var j=targetIndex+1; j<blocks.length; j++) {
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blocks[j].top += offset;
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blocks[j].block.css('top', blocks[j].top);
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}
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}
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}
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}
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onScrollorama();
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};
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// function for passing blockChange event callback
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scrollorama.onBlockChange = function(f) {
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onBlockChange = f;
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};
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// function for getting an array of scrollpoints
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// (top of each animation block and animation element scroll start point)
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scrollorama.getScrollpoints = function() {
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var scrollpoints = [];
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for (var i=0; i<blocks.length; i++) {
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scrollpoints.push(blocks[i].top);
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// go through the animations for each block
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if (blocks[i].animations.length && blocks[i].pin > 0) {
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for (var j=0; j<blocks[i].animations.length; j++) {
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var anim = blocks[i].animations[j];
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scrollpoints.push(blocks[i].top + anim.delay + anim.duration);
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}
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}
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}
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// make sure scrollpoints are in numeric order
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scrollpoints.sort(function(a,b){return a - b;});
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return scrollpoints;
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};
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// INIT
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init();
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return scrollorama;
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};
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})(jQuery); |