git-flow-cheatsheet/js/jquery.scrollorama.js
2012-07-31 12:59:15 +02:00

518 lines
17 KiB
JavaScript

/*
scrollorama - The jQuery plugin for doing cool scrolly stuff
by John Polacek (@johnpolacek)
Dual licensed under MIT and GPL.
*/
(function($) {
$.scrollorama = function(options) {
var scrollorama = this,
blocks = [],
browserPrefix = '',
onBlockChange = function() {},
latestKnownScrollY = 0,
ticking = false,
requestAnimFrame = window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function( callback ){
window.setTimeout(callback, 1000 / 60);
},
defaults = {offset:0, enablePin: true};
scrollorama.settings = $.extend({}, defaults, options);
scrollorama.blockIndex = 0;
if (options.blocks === undefined) { alert('ERROR: Must assign blocks class selector to scrollorama plugin'); }
// PRIVATE FUNCTIONS
function init() {
var i, block, didScroll = false;
if (typeof scrollorama.settings.blocks === 'string') { scrollorama.settings.blocks = $(scrollorama.settings.blocks); }
// set browser prefix
if ($.browser.mozilla) { browserPrefix = '-moz-'; }
if ($.browser.webkit) { browserPrefix = '-webkit-'; }
if ($.browser.opera) { browserPrefix = '-o-'; }
if ($.browser.msie) { browserPrefix = '-ms-'; }
// create blocks array to contain animation props
$('body').css('position','relative');
for (i=0; i<scrollorama.settings.blocks.length; i++) {
block = scrollorama.settings.blocks.eq(i);
blocks.push({
block: block,
top: block.offset().top - parseInt(block.css('margin-top'), 10),
pin: 0,
animations:[]
});
}
// convert block elements to absolute position
if (scrollorama.settings.enablePin.toString() === 'true') {
for (i=0; i<blocks.length; i++) {
blocks[i].block
.css('position', 'absolute')
.css('top', blocks[i].top);
}
}
$('body').prepend('<div id="scroll-wrap"></div>');
latestKnownScrollY = 0;
ticking = false;
$(window).on( 'scroll.scrollorama', onScroll );
}
function onScroll() {
latestKnownScrollY = window.scrollY;
requestTick();
}
function requestTick() {
if(!ticking) {
requestAnimFrame(function(){
onScrollorama();
update();
});
}
ticking = true;
}
function update() {
// reset the tick so we can
// capture the next onScroll
ticking = false;
}
function onScrollorama() {
var scrollTop = $(window).scrollTop(),
currBlockIndex = getCurrBlockIndex(scrollTop),
i, j, anim, startAnimPos, endAnimPos, animPercent, animVal;
// update all animations
for (i=0; i<blocks.length; i++) {
// go through the animations for each block
if (blocks[i].animations.length) {
for (j=0; j<blocks[i].animations.length; j++) {
anim = blocks[i].animations[j];
// if above current block, settings should be at start value
if (i > currBlockIndex) {
if (currBlockIndex !== i-1 && anim.baseline !== 'bottom') {
setProperty(anim.element, anim.property, anim.startVal);
}
if (blocks[i].pin) {
blocks[i].block
.css('position', 'absolute')
.css('top', blocks[i].top);
}
}
// if below current block, settings should be at end value
// unless on an element that gets animated when it hits the bottom of the viewport
else if (i < currBlockIndex) {
setProperty(anim.element, anim.property, anim.endVal);
if (blocks[i].pin) {
blocks[i].block
.css('position', 'absolute')
.css('top', (blocks[i].top + blocks[i].pin));
}
}
// otherwise, set values per scroll position
if (i === currBlockIndex || (currBlockIndex === i-1 && anim.baseline === 'bottom')) {
// if block gets pinned, set position fixed
if (blocks[i].pin && currBlockIndex === i) {
blocks[i].block
.css('position', 'fixed')
.css('top', 0);
}
// set start and end animation positions
startAnimPos = blocks[i].top + anim.delay;
if (anim.baseline === 'bottom') { startAnimPos -= $(window).height(); }
endAnimPos = startAnimPos + anim.duration;
// if scroll is before start of animation, set to start value
if (scrollTop < startAnimPos) {
setProperty(anim.element, anim.property, anim.startVal);
}
// if scroll is after end of animation, set to end value
else if (scrollTop > endAnimPos) {
setProperty(anim.element, anim.property, anim.endVal);
if (blocks[i].pin) {
blocks[i].block
.css('position', 'absolute')
.css('top', (blocks[i].top + blocks[i].pin));
}
}
// otherwise, set value based on scroll
else {
// calculate percent to animate
animPercent = (scrollTop - startAnimPos) / anim.duration;
// account for easing if there is any
if ( anim.easing && $.isFunction( $.easing[anim.easing] ) ) {
animPercent = $.easing[anim.easing]( animPercent, animPercent*1000, 0, 1, 1000 );
}
// then multiply the percent by the value range and calculate the new value
animVal = anim.startVal + (animPercent * (anim.endVal - anim.startVal));
setProperty(anim.element, anim.property, animVal);
}
}
}
}
}
// update blockIndex and trigger event if changed
if (scrollorama.blockIndex !== currBlockIndex) {
scrollorama.blockIndex = currBlockIndex;
onBlockChange();
}
}
function getCurrBlockIndex(scrollTop) {
var currBlockIndex = 0, i;
for (i=0; i<blocks.length; i++) {
// check if block is in view
if (blocks[i].top <= scrollTop - scrollorama.settings.offset) { currBlockIndex = i; }
}
return currBlockIndex;
}
function setProperty(target, prop, val) {
var scaleCSS, currentPosition;
if (prop === 'rotate' || prop === 'zoom' || prop === 'scale') {
if (prop === 'rotate') {
target.css(browserPrefix+'transform', 'rotate('+val+'deg)');
} else if (prop === 'zoom' || prop === 'scale') {
scaleCSS = 'scale('+val+')';
if (browserPrefix !== '-ms-') {
target.css(browserPrefix+'transform', scaleCSS);
} else {
target.css('zoom', scaleCSS);
}
}
}
else if(prop === 'background-position-x' || prop === 'background-position-y' ) {
currentPosition = target.css('background-position').split(' ');
if(prop === 'background-position-x') {
target.css('background-position',val+'px '+currentPosition[1]);
}
if(prop === 'background-position-y') {
target.css('background-position', currentPosition[0]+' '+val+'px');
}
}
else if(prop === 'text-shadow' ) {
target.css(prop,'0px 0px '+val+'px #ffffff');
} else {
target.css(prop, val);
}
}
// PUBLIC FUNCTIONS
scrollorama.animate = function(target) {
var targetIndex,
targetBlock,
anim,
offset,
i, j;
/*
target = animation target
arguments = array of animation parameters
anim = object that contains all animation params (created from arguments)
offset = positioning helper for pinning
animation parameters:
delay = amount of scrolling (in pixels) before animation starts
duration = amount of scrolling (in pixels) over which the animation occurs
property = css property being animated
start = start value of the property
end = end value of the property
pin = pin block during animation duration (applies to all animations within block)
baseline = top (default, when block reaches top of viewport) or bottom (when block first comies into view)
easing = just like jquery's easing functions
*/
// if string, convert to DOM object
if (typeof target === 'string') { target = $(target); }
// find block of target
for (i=0; i<blocks.length; i++) {
if (blocks[i].block.has(target).length) {
targetBlock = blocks[i];
targetIndex = i;
}
}
// add each animation to the blocks animations array from function arguments
for (i=1; i<arguments.length; i++) {
anim = arguments[i];
// for top/left/right/bottom, set relative positioning if static
if (anim.property === 'top' || anim.property === 'left' || anim.property === 'bottom' || anim.property === 'right' ) {
if (target.css('position') === 'static') { target.css('position','relative'); }
// set anim.start, anim.end defaults
cssValue = parseInt(target.css(anim.property),10);
if (anim.start === undefined) {
anim.start = isNaN(cssValue) ? 0 : cssValue;
} else if (anim.end === undefined) {
anim.end = isNaN(cssValue) ? 0 : cssValue;
}
}
// set anim.start/anim.end defaults for rotate, zoom/scale, letter-spacing
if (anim.property === 'rotate') {
if (anim.start === undefined) { anim.start = 0; }
if (anim.end === undefined) { anim.end = 0; }
} else if (anim.property === 'zoom' || anim.property === 'scale' ) {
if (anim.start === undefined) { anim.start = 1; }
if (anim.end === undefined) { anim.end = 1; }
} else if (anim.property === 'letter-spacing' && target.css(anim.property)) {
if (anim.start === undefined) { anim.start = 1; }
if (anim.end === undefined) { anim.end = 1; }
}
if (anim.baseline === undefined) {
if (anim.pin || targetBlock.pin || targetIndex === 0) {
anim.baseline = 'top';
} else {
anim.baseline = 'bottom';
}
}
if (anim.delay === undefined) { anim.delay = 0; }
targetBlock.animations.push({
element: target,
delay: anim.delay,
duration: anim.duration,
property: anim.property,
startVal: anim.start !== undefined ? anim.start : parseInt(target.css(anim.property),10), // if undefined, use current css value
endVal: anim.end !== undefined ? anim.end : parseInt(target.css(anim.property),10), // if undefined, use current css value
baseline: anim.baseline !== undefined ? anim.baseline : 'bottom',
easing: anim.easing
});
if (anim.pin) {
if (targetBlock.pin < anim.duration + anim.delay) {
offset = anim.duration + anim.delay - targetBlock.pin;
targetBlock.pin += offset;
// adjust positions of blocks below target block
for (j=targetIndex+1; j<blocks.length; j++) {
blocks[j].top += offset;
blocks[j].block.css('top', blocks[j].top);
}
}
}
}
onScrollorama();
};
// function for passing blockChange event callback
scrollorama.onBlockChange = function(f) {
onBlockChange = f;
};
// function for getting an array of scrollpoints
// (top of each animation block and animation element scroll start point)
scrollorama.getScrollpoints = function() {
var scrollpoints = [],i,j,anim;
for (i=0; i<blocks.length; i++) {
scrollpoints.push(blocks[i].top);
// go through the animations for each block
if (blocks[i].animations.length && blocks[i].pin > 0) {
for (j=0; j<blocks[i].animations.length; j++) {
anim = blocks[i].animations[j];
scrollpoints.push(blocks[i].top + anim.delay + anim.duration);
}
}
}
// make sure scrollpoints are in numeric order
scrollpoints.sort(function(a,b) {return a - b;});
return scrollpoints;
};
// Remove scrollorama
scrollorama.destroy = function () {
// Remove animations
for (i=0; i<blocks.length; i++) {
// Remove CSS rules
blocks[i].block.css({
top: '',
position: ''
});
// Remove scrolloroma-specific attributes
delete blocks[i].animations;
delete blocks[i].top;
delete blocks[i].pin;
}
// Unbind the window scroll event
$(window).off('scroll.scrollorama');
$('#scroll-wrap').remove();
// Remove the scrolloroma object
delete scrollorama;
};
// INIT
init();
return scrollorama;
};
//
// Easing functions from jQuery UI
//
$.extend($.easing, {
def: 'easeOutQuad',
swing: function (x, t, b, c, d) {
//alert($.easing.default);
return $.easing[$.easing.def](x, t, b, c, d);
},
easeInQuad: function (x, t, b, c, d) {
return c*(t/=d)*t + b;
},
easeOutQuad: function (x, t, b, c, d) {
return -c *(t/=d)*(t-2) + b;
},
easeInOutQuad: function (x, t, b, c, d) {
if ((t/=d/2) < 1) { return c/2*t*t + b; }
return -c/2 * ((--t)*(t-2) - 1) + b;
},
easeInCubic: function (x, t, b, c, d) {
return c*(t/=d)*t*t + b;
},
easeOutCubic: function (x, t, b, c, d) {
return c*((t=t/d-1)*t*t + 1) + b;
},
easeInOutCubic: function (x, t, b, c, d) {
if ((t/=d/2) < 1) { return c/2*t*t*t + b; }
return c/2*((t-=2)*t*t + 2) + b;
},
easeInQuart: function (x, t, b, c, d) {
return c*(t/=d)*t*t*t + b;
},
easeOutQuart: function (x, t, b, c, d) {
return -c * ((t=t/d-1)*t*t*t - 1) + b;
},
easeInOutQuart: function (x, t, b, c, d) {
if ((t/=d/2) < 1) { return c/2*t*t*t*t + b; }
return -c/2 * ((t-=2)*t*t*t - 2) + b;
},
easeInQuint: function (x, t, b, c, d) {
return c*(t/=d)*t*t*t*t + b;
},
easeOutQuint: function (x, t, b, c, d) {
return c*((t=t/d-1)*t*t*t*t + 1) + b;
},
easeInOutQuint: function (x, t, b, c, d) {
if ((t/=d/2) < 1) { return c/2*t*t*t*t*t + b; }
return c/2*((t-=2)*t*t*t*t + 2) + b;
},
easeInSine: function (x, t, b, c, d) {
return -c * Math.cos(t/d * (Math.PI/2)) + c + b;
},
easeOutSine: function (x, t, b, c, d) {
return c * Math.sin(t/d * (Math.PI/2)) + b;
},
easeInOutSine: function (x, t, b, c, d) {
return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
},
easeInExpo: function (x, t, b, c, d) {
return (t===0) ? b : c * Math.pow(2, 10 * (t/d - 1)) + b;
},
easeOutExpo: function (x, t, b, c, d) {
return (t===d) ? b+c : c * (-Math.pow(2, -10 * t/d) + 1) + b;
},
easeInOutExpo: function (x, t, b, c, d) {
if (t===0) { return b; }
if (t===d) { return b+c; }
if ((t/=d/2) < 1) { return c/2 * Math.pow(2, 10 * (t - 1)) + b; }
return c/2 * (-Math.pow(2, -10 * --t) + 2) + b;
},
easeInCirc: function (x, t, b, c, d) {
return -c * (Math.sqrt(1 - (t/=d)*t) - 1) + b;
},
easeOutCirc: function (x, t, b, c, d) {
return c * Math.sqrt(1 - (t=t/d-1)*t) + b;
},
easeInOutCirc: function (x, t, b, c, d) {
if ((t/=d/2) < 1) { return -c/2 * (Math.sqrt(1 - t*t) - 1) + b; }
return c/2 * (Math.sqrt(1 - (t-=2)*t) + 1) + b;
},
easeInElastic: function (x, t, b, c, d) {
var s=1.70158,p=0,a=c;
if (t===0) { return b; }
if ((t/=d)===1) { return b+c; }
if (!p) { p=d*0.3; }
if (a < Math.abs(c)) { a=c; s=p/4; }
else{ s = p/(2*Math.PI) * Math.asin (c/a); }
return -(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
},
easeOutElastic: function (x, t, b, c, d) {
var s=1.70158,p=0,a=c;
if (t===0) { return b; }
if ((t/=d)===1) { return b+c; }
if (!p) { p=d*0.3; }
if (a < Math.abs(c)) { a=c; s=p/4; }
else { s = p/(2*Math.PI) * Math.asin (c/a); }
return a*Math.pow(2,-10*t) * Math.sin( (t*d-s)*(2*Math.PI)/p ) + c + b;
},
easeInOutElastic: function (x, t, b, c, d) {
var s=1.70158,p=0,a=c;
if (t===0) { return b; }
if ((t/=d/2)===2) { return b+c; }
if (!p) { p=d*(0.3*1.5); }
if (a < Math.abs(c)) { a=c; s=p/4; }
else { s = p/(2*Math.PI) * Math.asin (c/a); }
if (t < 1) { return -0.5*(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b; }
return a*Math.pow(2,-10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )*0.5 + c + b;
},
easeInBack: function (x, t, b, c, d, s) {
if (s === undefined) { s = 1.70158; }
return c*(t/=d)*t*((s+1)*t - s) + b;
},
easeOutBack: function (x, t, b, c, d, s) {
if (s === undefined) { s = 1.70158; }
return c*((t=t/d-1)*t*((s+1)*t + s) + 1) + b;
},
easeInOutBack: function (x, t, b, c, d, s) {
if (s === undefined) { s = 1.70158; }
if ((t/=d/2) < 1) { return c/2*(t*t*(((s*=(1.525))+1)*t - s)) + b; }
return c/2*((t-=2)*t*(((s*=(1.525))+1)*t + s) + 2) + b;
},
easeInBounce: function (x, t, b, c, d) {
return c - $.easing.easeOutBounce (x, d-t, 0, c, d) + b;
},
easeOutBounce: function (x, t, b, c, d) {
if ((t/=d) < (1/2.75)) {
return c*(7.5625*t*t) + b;
} else if (t < (2/2.75)) {
return c*(7.5625*(t-=(1.5/2.75))*t + 0.75) + b;
} else if (t < (2.5/2.75)) {
return c*(7.5625*(t-=(2.25/2.75))*t + 0.9375) + b;
} else {
return c*(7.5625*(t-=(2.625/2.75))*t + 0.984375) + b;
}
},
easeInOutBounce: function (x, t, b, c, d) {
if (t < d/2) { return $.easing.easeInBounce (x, t*2, 0, c, d) * 0.5 + b; }
return $.easing.easeOutBounce (x, t*2-d, 0, c, d) * 0.5 + c*0.5 + b;
}
});
})(jQuery);