Template:Hangzhou-H14Z/js/skrollr

/*!

* skrollr core
*
* Alexander Prinzhorn - https://github.com/Prinzhorn/skrollr
*
* Free to use under terms of MIT license
*/

(function(window, document, undefined) { 'use strict';

/* * Global api. */ var skrollr = window.skrollr = { get: function() { return _instance; }, //Main entry point. init: function(options) { return _instance || new Skrollr(options); }, VERSION: '0.6.21' };

//Minify optimization. var hasProp = Object.prototype.hasOwnProperty; var Math = window.Math; var getStyle = window.getComputedStyle;

//They will be filled when skrollr gets initialized. var documentElement; var body;

var EVENT_TOUCHSTART = 'touchstart'; var EVENT_TOUCHMOVE = 'touchmove'; var EVENT_TOUCHCANCEL = 'touchcancel'; var EVENT_TOUCHEND = 'touchend';

var SKROLLABLE_CLASS = 'skrollable'; var SKROLLABLE_BEFORE_CLASS = SKROLLABLE_CLASS + '-before'; var SKROLLABLE_BETWEEN_CLASS = SKROLLABLE_CLASS + '-between'; var SKROLLABLE_AFTER_CLASS = SKROLLABLE_CLASS + '-after';

var SKROLLR_CLASS = 'skrollr'; var NO_SKROLLR_CLASS = 'no-' + SKROLLR_CLASS; var SKROLLR_DESKTOP_CLASS = SKROLLR_CLASS + '-desktop'; var SKROLLR_MOBILE_CLASS = SKROLLR_CLASS + '-mobile';

var DEFAULT_EASING = 'linear'; var DEFAULT_DURATION = 1000;//ms var DEFAULT_MOBILE_DECELERATION = 0.004;//pixel/ms²

var DEFAULT_SMOOTH_SCROLLING_DURATION = 200;//ms

var ANCHOR_START = 'start'; var ANCHOR_END = 'end'; var ANCHOR_CENTER = 'center'; var ANCHOR_BOTTOM = 'bottom';

//The property which will be added to the DOM element to hold the ID of the skrollable. var SKROLLABLE_ID_DOM_PROPERTY = '___skrollable_id';

var rxTouchIgnoreTags = /^(?:input|textarea|button|select)$/i;

var rxTrim = /^\s+|\s+$/g;

//Find all data-attributes. data-[_constant]-[offset]-[anchor]-[anchor]. var rxKeyframeAttribute = /^data(?:-(_\w+))?(?:-?(-?\d*\.?\d+p?))?(?:-?(start|end|top|center|bottom))?(?:-?(top|center|bottom))?$/;

var rxPropValue = /\s*([\w\-\[\]]+)\s*:\s*(.+?)\s*(?:;|$)/gi;

//Easing function names follow the property in square brackets. var rxPropEasing = /^([a-z\-]+)\[(\w+)\]$/;

var rxCamelCase = /-([a-z])/g; var rxCamelCaseFn = function(str, letter) { return letter.toUpperCase(); };

//Numeric values with optional sign. var rxNumericValue = /[\-+]?[\d]*\.?[\d]+/g;

//Used to replace occurences of {?} with a number. var rxInterpolateString = /\{\?\}/g;

//Finds rgb(a) colors, which don't use the percentage notation. var rxRGBAIntegerColor = /rgba?\(\s*-?\d+\s*,\s*-?\d+\s*,\s*-?\d+/g;

//Finds all gradients. var rxGradient = /[a-z\-]+-gradient/g;

//Vendor prefix. Will be set once skrollr gets initialized. var theCSSPrefix = ; var theDashedCSSPrefix = ;

//Will be called once (when skrollr gets initialized). var detectCSSPrefix = function() { //Only relevant prefixes. May be extended. //Could be dangerous if there will ever be a CSS property which actually starts with "ms". Don't hope so. var rxPrefixes = /^(?:O|Moz|webkit|ms)|(?:-(?:o|moz|webkit|ms)-)/;

//Detect prefix for current browser by finding the first property using a prefix. if(!getStyle) { return; }

var style = getStyle(body, null);

for(var k in style) { //We check the key and if the key is a number, we check the value as well, because safari's getComputedStyle returns some weird array-like thingy. theCSSPrefix = (k.match(rxPrefixes) || (+k == k && style[k].match(rxPrefixes)));

if(theCSSPrefix) { break; } }

//Did we even detect a prefix? if(!theCSSPrefix) { theCSSPrefix = theDashedCSSPrefix = ;

return; }

theCSSPrefix = theCSSPrefix[0];

//We could have detected either a dashed prefix or this camelCaseish-inconsistent stuff. if(theCSSPrefix.slice(0,1) === '-') { theDashedCSSPrefix = theCSSPrefix;

//There's no logic behind these. Need a look up. theCSSPrefix = ({ '-webkit-': 'webkit', '-moz-': 'Moz', '-ms-': 'ms', '-o-': 'O' })[theCSSPrefix]; } else { theDashedCSSPrefix = '-' + theCSSPrefix.toLowerCase() + '-'; } };

var polyfillRAF = function() { var requestAnimFrame = window.requestAnimationFrame || window[theCSSPrefix.toLowerCase() + 'RequestAnimationFrame'];

var lastTime = _now();

if(_isMobile || !requestAnimFrame) { requestAnimFrame = function(callback) { //How long did it take to render? var deltaTime = _now() - lastTime; var delay = Math.max(0, 1000 / 60 - deltaTime);

return window.setTimeout(function() { lastTime = _now(); callback(); }, delay); }; }

return requestAnimFrame; };

var polyfillCAF = function() { var cancelAnimFrame = window.cancelAnimationFrame || window[theCSSPrefix.toLowerCase() + 'CancelAnimationFrame'];

if(_isMobile || !cancelAnimFrame) { cancelAnimFrame = function(timeout) { return window.clearTimeout(timeout); }; }

return cancelAnimFrame; };

//Built-in easing functions. var easings = { begin: function() { return 0; }, end: function() { return 1; }, linear: function(p) { return p; }, quadratic: function(p) { return p * p; }, cubic: function(p) { return p * p * p; }, swing: function(p) { return (-Math.cos(p * Math.PI) / 2) + 0.5; }, sqrt: function(p) { return Math.sqrt(p); }, outCubic: function(p) { return (Math.pow((p - 1), 3) + 1); }, //see https://www.desmos.com/calculator/tbr20s8vd2 for how I did this bounce: function(p) { var a;

if(p <= 0.5083) { a = 3; } else if(p <= 0.8489) { a = 9; } else if(p <= 0.96208) { a = 27; } else if(p <= 0.99981) { a = 91; } else { return 1; }

return 1 - Math.abs(3 * Math.cos(p * a * 1.028) / a); } };

/** * Constructor. */ function Skrollr(options) { documentElement = document.documentElement; body = document.body;

detectCSSPrefix();

_instance = this;

options = options || {};

_constants = options.constants || {};

//We allow defining custom easings or overwrite existing. if(options.easing) { for(var e in options.easing) { easings[e] = options.easing[e]; } }

_edgeStrategy = options.edgeStrategy || 'set';

_listeners = { //Function to be called right before rendering. beforerender: options.beforerender,

//Function to be called right after finishing rendering. render: options.render };

//forceHeight is true by default _forceHeight = options.forceHeight !== false;

if(_forceHeight) { _scale = options.scale || 1; }

_mobileDeceleration = options.mobileDeceleration || DEFAULT_MOBILE_DECELERATION;

_smoothScrollingEnabled = options.smoothScrolling !== false; _smoothScrollingDuration = options.smoothScrollingDuration || DEFAULT_SMOOTH_SCROLLING_DURATION;

//Dummy object. Will be overwritten in the _render method when smooth scrolling is calculated. _smoothScrolling = { targetTop: _instance.getScrollTop() };

//A custom check function may be passed. _isMobile = ((options.mobileCheck || function() { return (/Android|iPhone|iPad|iPod|BlackBerry/i).test(navigator.userAgent || navigator.vendor || window.opera); })());

if(_isMobile) { _skrollrBody = document.getElementById('skrollr-body');

//Detect 3d transform if there's a skrollr-body (only needed for #skrollr-body). if(_skrollrBody) { _detect3DTransforms(); }

_initMobile(); _updateClass(documentElement, [SKROLLR_CLASS, SKROLLR_MOBILE_CLASS], [NO_SKROLLR_CLASS]); } else { _updateClass(documentElement, [SKROLLR_CLASS, SKROLLR_DESKTOP_CLASS], [NO_SKROLLR_CLASS]); }

//Triggers parsing of elements and a first reflow. _instance.refresh();

_addEvent(window, 'resize orientationchange', function() { var width = documentElement.clientWidth; var height = documentElement.clientHeight;

//Only reflow if the size actually changed (#271). if(height !== _lastViewportHeight || width !== _lastViewportWidth) { _lastViewportHeight = height; _lastViewportWidth = width;

_requestReflow = true; } });

var requestAnimFrame = polyfillRAF();

//Let's go. (function animloop(){ _render(); _animFrame = requestAnimFrame(animloop); }());

return _instance; }

/** * (Re)parses some or all elements. */ Skrollr.prototype.refresh = function(elements) { var elementIndex; var elementsLength; var ignoreID = false;

//Completely reparse anything without argument. if(elements === undefined) { //Ignore that some elements may already have a skrollable ID. ignoreID = true;

_skrollables = []; _skrollableIdCounter = 0;

elements = document.getElementsByTagName('*'); } else { //We accept a single element or an array of elements. elements = [].concat(elements); }

elementIndex = 0; elementsLength = elements.length;

for(; elementIndex < elementsLength; elementIndex++) { var el = elements[elementIndex]; var anchorTarget = el; var keyFrames = [];

//If this particular element should be smooth scrolled. var smoothScrollThis = _smoothScrollingEnabled;

//The edge strategy for this particular element. var edgeStrategy = _edgeStrategy;

if(!el.attributes) { continue; }

//Iterate over all attributes and search for key frame attributes. var attributeIndex = 0; var attributesLength = el.attributes.length;

for (; attributeIndex < attributesLength; attributeIndex++) { var attr = el.attributes[attributeIndex];

if(attr.name === 'data-anchor-target') { anchorTarget = document.querySelector(attr.value);

if(anchorTarget === null) { throw 'Unable to find anchor target "' + attr.value + '"'; }

continue; }

//Global smooth scrolling can be overridden by the element attribute. if(attr.name === 'data-smooth-scrolling') { smoothScrollThis = attr.value !== 'off';

continue; }

//Global edge strategy can be overridden by the element attribute. if(attr.name === 'data-edge-strategy') { edgeStrategy = attr.value;

continue; }

var match = attr.name.match(rxKeyframeAttribute);

if(match === null) { continue; }

var kf = { props: attr.value, //Point back to the element as well. element: el };

keyFrames.push(kf);

var constant = match[1];

if(constant) { //Strip the underscore prefix. kf.constant = constant.substr(1); }

//Get the key frame offset. var offset = match[2];

//Is it a percentage offset? if(/p$/.test(offset)) { kf.isPercentage = true; kf.offset = (offset.slice(0, -1) | 0) / 100; } else { kf.offset = (offset | 0); }

var anchor1 = match[3];

//If second anchor is not set, the first will be taken for both. var anchor2 = match[4] || anchor1;

//"absolute" (or "classic") mode, where numbers mean absolute scroll offset. if(!anchor1 || anchor1 === ANCHOR_START || anchor1 === ANCHOR_END) { kf.mode = 'absolute';

//data-end needs to be calculated after all key frames are known. if(anchor1 === ANCHOR_END) { kf.isEnd = true; } else if(!kf.isPercentage) { //For data-start we can already set the key frame w/o calculations. //#59: "scale" options should only affect absolute mode. kf.offset = kf.offset * _scale; } } //"relative" mode, where numbers are relative to anchors. else { kf.mode = 'relative'; kf.anchors = [anchor1, anchor2]; } }

//Does this element have key frames? if(!keyFrames.length) { continue; }

//Will hold the original style and class attributes before we controlled the element (see #80). var styleAttr, classAttr;

var id;

if(!ignoreID && SKROLLABLE_ID_DOM_PROPERTY in el) { //We already have this element under control. Grab the corresponding skrollable id. id = el[SKROLLABLE_ID_DOM_PROPERTY]; styleAttr = _skrollables[id].styleAttr; classAttr = _skrollables[id].classAttr; } else { //It's an unknown element. Asign it a new skrollable id. id = (el[SKROLLABLE_ID_DOM_PROPERTY] = _skrollableIdCounter++); styleAttr = el.style.cssText; classAttr = _getClass(el); }

_skrollables[id] = { element: el, styleAttr: styleAttr, classAttr: classAttr, anchorTarget: anchorTarget, keyFrames: keyFrames, smoothScrolling: smoothScrollThis, edgeStrategy: edgeStrategy };

_updateClass(el, [SKROLLABLE_CLASS], []); }

//Reflow for the first time. _reflow();

//Now that we got all key frame numbers right, actually parse the properties. elementIndex = 0; elementsLength = elements.length;

for(; elementIndex < elementsLength; elementIndex++) { var sk = _skrollables[elements[elementIndex][SKROLLABLE_ID_DOM_PROPERTY]];

if(sk === undefined) { continue; }

//Parse the property string to objects _parseProps(sk);

//Fill key frames with missing properties from left and right _fillProps(sk); }

return _instance; };

/** * Transform "relative" mode to "absolute" mode. * That is, calculate anchor position and offset of element. */ Skrollr.prototype.relativeToAbsolute = function(element, viewportAnchor, elementAnchor) { var viewportHeight = documentElement.clientHeight; var box = element.getBoundingClientRect(); var absolute = box.top;

//#100: IE doesn't supply "height" with getBoundingClientRect. var boxHeight = box.bottom - box.top;

if(viewportAnchor === ANCHOR_BOTTOM) { absolute -= viewportHeight; } else if(viewportAnchor === ANCHOR_CENTER) { absolute -= viewportHeight / 2; }

if(elementAnchor === ANCHOR_BOTTOM) { absolute += boxHeight; } else if(elementAnchor === ANCHOR_CENTER) { absolute += boxHeight / 2; }

//Compensate scrolling since getBoundingClientRect is relative to viewport. absolute += _instance.getScrollTop();

return (absolute + 0.5) | 0; };

/** * Animates scroll top to new position. */ Skrollr.prototype.animateTo = function(top, options) { options = options || {};

var now = _now(); var scrollTop = _instance.getScrollTop();

//Setting this to a new value will automatically cause the current animation to stop, if any. _scrollAnimation = { startTop: scrollTop, topDiff: top - scrollTop, targetTop: top, duration: options.duration || DEFAULT_DURATION, startTime: now, endTime: now + (options.duration || DEFAULT_DURATION), easing: easings[options.easing || DEFAULT_EASING], done: options.done };

//Don't queue the animation if there's nothing to animate. if(!_scrollAnimation.topDiff) { if(_scrollAnimation.done) { _scrollAnimation.done.call(_instance, false); }

_scrollAnimation = undefined; }

return _instance; };

/** * Stops animateTo animation. */ Skrollr.prototype.stopAnimateTo = function() { if(_scrollAnimation && _scrollAnimation.done) { _scrollAnimation.done.call(_instance, true); }

_scrollAnimation = undefined; };

/** * Returns if an animation caused by animateTo is currently running. */ Skrollr.prototype.isAnimatingTo = function() { return !!_scrollAnimation; };

Skrollr.prototype.setScrollTop = function(top, force) { _forceRender = (force === true);

if(_isMobile) { _mobileOffset = Math.min(Math.max(top, 0), _maxKeyFrame); } else { window.scrollTo(0, top); }

return _instance; };

Skrollr.prototype.getScrollTop = function() { if(_isMobile) { return _mobileOffset; } else { return window.pageYOffset || documentElement.scrollTop || body.scrollTop || 0; } };

Skrollr.prototype.getMaxScrollTop = function() { return _maxKeyFrame; };

Skrollr.prototype.on = function(name, fn) { _listeners[name] = fn;

return _instance; };

Skrollr.prototype.off = function(name) { delete _listeners[name];

return _instance; };

Skrollr.prototype.destroy = function() { var cancelAnimFrame = polyfillCAF(); cancelAnimFrame(_animFrame); _removeAllEvents();

_updateClass(documentElement, [NO_SKROLLR_CLASS], [SKROLLR_CLASS, SKROLLR_DESKTOP_CLASS, SKROLLR_MOBILE_CLASS]);

var skrollableIndex = 0; var skrollablesLength = _skrollables.length;

for(; skrollableIndex < skrollablesLength; skrollableIndex++) { _reset(_skrollables[skrollableIndex].element); }

documentElement.style.overflow = body.style.overflow = 'auto'; documentElement.style.height = body.style.height = 'auto';

if(_skrollrBody) { skrollr.setStyle(_skrollrBody, 'transform', 'none'); }

_instance = undefined; _skrollrBody = undefined; _listeners = undefined; _forceHeight = undefined; _maxKeyFrame = 0; _scale = 1; _constants = undefined; _mobileDeceleration = undefined; _direction = 'down'; _lastTop = -1; _lastViewportWidth = 0; _lastViewportHeight = 0; _requestReflow = false; _scrollAnimation = undefined; _smoothScrollingEnabled = undefined; _smoothScrollingDuration = undefined; _smoothScrolling = undefined; _forceRender = undefined; _skrollableIdCounter = 0; _edgeStrategy = undefined; _isMobile = false; _mobileOffset = 0; _translateZ = undefined; };

/* Private methods. */

var _initMobile = function() { var initialElement; var initialTouchY; var initialTouchX; var currentElement; var currentTouchY; var currentTouchX; var lastTouchY; var deltaY;

var initialTouchTime; var currentTouchTime; var lastTouchTime; var deltaTime;

_addEvent(documentElement, [EVENT_TOUCHSTART, EVENT_TOUCHMOVE, EVENT_TOUCHCANCEL, EVENT_TOUCHEND].join(' '), function(e) { var touch = e.changedTouches[0];

currentElement = e.target;

//We don't want text nodes. while(currentElement.nodeType === 3) { currentElement = currentElement.parentNode; }

currentTouchY = touch.clientY; currentTouchX = touch.clientX; currentTouchTime = e.timeStamp;

if(!rxTouchIgnoreTags.test(currentElement.tagName)) { e.preventDefault(); }

switch(e.type) { case EVENT_TOUCHSTART: //The last element we tapped on. if(initialElement) { initialElement.blur(); }

_instance.stopAnimateTo();

initialElement = currentElement;

initialTouchY = lastTouchY = currentTouchY; initialTouchX = currentTouchX; initialTouchTime = currentTouchTime;

break; case EVENT_TOUCHMOVE: //Prevent default event on touchIgnore elements in case they don't have focus yet. if(rxTouchIgnoreTags.test(currentElement.tagName) && document.activeElement !== currentElement) { e.preventDefault(); }

deltaY = currentTouchY - lastTouchY; deltaTime = currentTouchTime - lastTouchTime;

_instance.setScrollTop(_mobileOffset - deltaY, true);

lastTouchY = currentTouchY; lastTouchTime = currentTouchTime; break; default: case EVENT_TOUCHCANCEL: case EVENT_TOUCHEND: var distanceY = initialTouchY - currentTouchY; var distanceX = initialTouchX - currentTouchX; var distance2 = distanceX * distanceX + distanceY * distanceY;

//Check if it was more like a tap (moved less than 7px). if(distance2 < 49) { if(!rxTouchIgnoreTags.test(initialElement.tagName)) { initialElement.focus();

//It was a tap, click the element. var clickEvent = document.createEvent('MouseEvents'); clickEvent.initMouseEvent('click', true, true, e.view, 1, touch.screenX, touch.screenY, touch.clientX, touch.clientY, e.ctrlKey, e.altKey, e.shiftKey, e.metaKey, 0, null); initialElement.dispatchEvent(clickEvent); }

return; }

initialElement = undefined;

var speed = deltaY / deltaTime;

//Cap speed at 3 pixel/ms. speed = Math.max(Math.min(speed, 3), -3);

var duration = Math.abs(speed / _mobileDeceleration); var targetOffset = speed * duration + 0.5 * _mobileDeceleration * duration * duration; var targetTop = _instance.getScrollTop() - targetOffset;

//Relative duration change for when scrolling above bounds. var targetRatio = 0;

//Change duration proportionally when scrolling would leave bounds. if(targetTop > _maxKeyFrame) { targetRatio = (_maxKeyFrame - targetTop) / targetOffset;

targetTop = _maxKeyFrame; } else if(targetTop < 0) { targetRatio = -targetTop / targetOffset;

targetTop = 0; }

duration = duration * (1 - targetRatio);

_instance.animateTo((targetTop + 0.5) | 0, {easing: 'outCubic', duration: duration}); break; } });

//Just in case there has already been some native scrolling, reset it. window.scrollTo(0, 0); documentElement.style.overflow = body.style.overflow = 'hidden'; };

/** * Updates key frames which depend on others / need to be updated on resize. * That is "end" in "absolute" mode and all key frames in "relative" mode. * Also handles constants, because they may change on resize. */ var _updateDependentKeyFrames = function() { var viewportHeight = documentElement.clientHeight; var processedConstants = _processConstants(); var skrollable; var element; var anchorTarget; var keyFrames; var keyFrameIndex; var keyFramesLength; var kf; var skrollableIndex; var skrollablesLength; var offset; var constantValue;

//First process all relative-mode elements and find the max key frame. skrollableIndex = 0; skrollablesLength = _skrollables.length;

for(; skrollableIndex < skrollablesLength; skrollableIndex++) { skrollable = _skrollables[skrollableIndex]; element = skrollable.element; anchorTarget = skrollable.anchorTarget; keyFrames = skrollable.keyFrames;

keyFrameIndex = 0; keyFramesLength = keyFrames.length;

for(; keyFrameIndex < keyFramesLength; keyFrameIndex++) { kf = keyFrames[keyFrameIndex];

offset = kf.offset; constantValue = processedConstants[kf.constant] || 0;

kf.frame = offset;

if(kf.isPercentage) { //Convert the offset to percentage of the viewport height. offset = offset * viewportHeight;

//Absolute + percentage mode. kf.frame = offset; }

if(kf.mode === 'relative') { _reset(element);

kf.frame = _instance.relativeToAbsolute(anchorTarget, kf.anchors[0], kf.anchors[1]) - offset;

_reset(element, true); }

kf.frame += constantValue;

//Only search for max key frame when forceHeight is enabled. if(_forceHeight) { //Find the max key frame, but don't use one of the data-end ones for comparison. if(!kf.isEnd && kf.frame > _maxKeyFrame) { _maxKeyFrame = kf.frame; } } } }

//#133: The document can be larger than the maxKeyFrame we found. _maxKeyFrame = Math.max(_maxKeyFrame, _getDocumentHeight());

//Now process all data-end keyframes. skrollableIndex = 0; skrollablesLength = _skrollables.length;

for(; skrollableIndex < skrollablesLength; skrollableIndex++) { skrollable = _skrollables[skrollableIndex]; keyFrames = skrollable.keyFrames;

keyFrameIndex = 0; keyFramesLength = keyFrames.length;

for(; keyFrameIndex < keyFramesLength; keyFrameIndex++) { kf = keyFrames[keyFrameIndex];

constantValue = processedConstants[kf.constant] || 0;

if(kf.isEnd) { kf.frame = _maxKeyFrame - kf.offset + constantValue; } }

skrollable.keyFrames.sort(_keyFrameComparator); } };

/** * Calculates and sets the style properties for the element at the given frame. * @param fakeFrame The frame to render at when smooth scrolling is enabled. * @param actualFrame The actual frame we are at. */ var _calcSteps = function(fakeFrame, actualFrame) { //Iterate over all skrollables. var skrollableIndex = 0; var skrollablesLength = _skrollables.length;

for(; skrollableIndex < skrollablesLength; skrollableIndex++) { var skrollable = _skrollables[skrollableIndex]; var element = skrollable.element; var frame = skrollable.smoothScrolling ? fakeFrame : actualFrame; var frames = skrollable.keyFrames; var firstFrame = frames[0].frame; var lastFrame = frames[frames.length - 1].frame; var beforeFirst = frame < firstFrame; var afterLast = frame > lastFrame; var firstOrLastFrame = frames[beforeFirst ? 0 : frames.length - 1]; var key; var value;

//If we are before/after the first/last frame, set the styles according to the given edge strategy. if(beforeFirst || afterLast) { //Check if we already handled this edge case last time. //Note: using setScrollTop it's possible that we jumped from one edge to the other. if(beforeFirst && skrollable.edge === -1 || afterLast && skrollable.edge === 1) { continue; }

//Add the skrollr-before or -after class. _updateClass(element, [beforeFirst ? SKROLLABLE_BEFORE_CLASS : SKROLLABLE_AFTER_CLASS], [SKROLLABLE_BEFORE_CLASS, SKROLLABLE_BETWEEN_CLASS, SKROLLABLE_AFTER_CLASS]);

//Remember that we handled the edge case (before/after the first/last keyframe). skrollable.edge = beforeFirst ? -1 : 1;

switch(skrollable.edgeStrategy) { case 'reset': _reset(element); continue; case 'ease': //Handle this case like it would be exactly at first/last keyframe and just pass it on. frame = firstOrLastFrame.frame; break; default: case 'set': var props = firstOrLastFrame.props;

for(key in props) { if(hasProp.call(props, key)) { value = _interpolateString(props[key].value);

skrollr.setStyle(element, key, value); } }

continue; } } else { //Did we handle an edge last time? if(skrollable.edge !== 0) { _updateClass(element, [SKROLLABLE_CLASS, SKROLLABLE_BETWEEN_CLASS], [SKROLLABLE_BEFORE_CLASS, SKROLLABLE_AFTER_CLASS]); skrollable.edge = 0; } }

//Find out between which two key frames we are right now. var keyFrameIndex = 0; var framesLength = frames.length - 1;

for(; keyFrameIndex < framesLength; keyFrameIndex++) { if(frame >= frames[keyFrameIndex].frame && frame <= frames[keyFrameIndex + 1].frame) { var left = frames[keyFrameIndex]; var right = frames[keyFrameIndex + 1];

for(key in left.props) { if(hasProp.call(left.props, key)) { var progress = (frame - left.frame) / (right.frame - left.frame);

//Transform the current progress using the given easing function. progress = left.props[key].easing(progress);

//Interpolate between the two values value = _calcInterpolation(left.props[key].value, right.props[key].value, progress);

value = _interpolateString(value);

skrollr.setStyle(element, key, value); } }

break; } } } };

/** * Renders all elements. */ var _render = function() { if(_requestReflow) { _requestReflow = false; _reflow(); }

//We may render something else than the actual scrollbar position. var renderTop = _instance.getScrollTop();

//If there's an animation, which ends in current render call, call the callback after rendering. var afterAnimationCallback; var now = _now(); var progress;

//Before actually rendering handle the scroll animation, if any. if(_scrollAnimation) { //It's over if(now >= _scrollAnimation.endTime) { renderTop = _scrollAnimation.targetTop; afterAnimationCallback = _scrollAnimation.done; _scrollAnimation = undefined; } else { //Map the current progress to the new progress using given easing function. progress = _scrollAnimation.easing((now - _scrollAnimation.startTime) / _scrollAnimation.duration);

renderTop = (_scrollAnimation.startTop + progress * _scrollAnimation.topDiff) | 0; }

_instance.setScrollTop(renderTop, true); } //Smooth scrolling only if there's no animation running and if we're not forcing the rendering. else if(!_forceRender) { var smoothScrollingDiff = _smoothScrolling.targetTop - renderTop;

//The user scrolled, start new smooth scrolling. if(smoothScrollingDiff) { _smoothScrolling = { startTop: _lastTop, topDiff: renderTop - _lastTop, targetTop: renderTop, startTime: _lastRenderCall, endTime: _lastRenderCall + _smoothScrollingDuration }; }

//Interpolate the internal scroll position (not the actual scrollbar). if(now <= _smoothScrolling.endTime) { //Map the current progress to the new progress using easing function. progress = easings.sqrt((now - _smoothScrolling.startTime) / _smoothScrollingDuration);

renderTop = (_smoothScrolling.startTop + progress * _smoothScrolling.topDiff) | 0; } }

//That's were we actually "scroll" on mobile. if(_isMobile && _skrollrBody) { //Set the transform ("scroll it"). skrollr.setStyle(_skrollrBody, 'transform', 'translate(0, ' + -(_mobileOffset) + 'px) ' + _translateZ); }

//Did the scroll position even change? if(_forceRender || _lastTop !== renderTop) { //Remember in which direction are we scrolling? _direction = (renderTop > _lastTop) ? 'down' : (renderTop < _lastTop ? 'up' : _direction);

_forceRender = false;

var listenerParams = { curTop: renderTop, lastTop: _lastTop, maxTop: _maxKeyFrame, direction: _direction };

//Tell the listener we are about to render. var continueRendering = _listeners.beforerender && _listeners.beforerender.call(_instance, listenerParams);

//The beforerender listener function is able the cancel rendering. if(continueRendering !== false) { //Now actually interpolate all the styles. _calcSteps(renderTop, _instance.getScrollTop());

//Remember when we last rendered. _lastTop = renderTop;

if(_listeners.render) { _listeners.render.call(_instance, listenerParams); } }

if(afterAnimationCallback) { afterAnimationCallback.call(_instance, false); } }

_lastRenderCall = now; };

/** * Parses the properties for each key frame of the given skrollable. */ var _parseProps = function(skrollable) { //Iterate over all key frames var keyFrameIndex = 0; var keyFramesLength = skrollable.keyFrames.length;

for(; keyFrameIndex < keyFramesLength; keyFrameIndex++) { var frame = skrollable.keyFrames[keyFrameIndex]; var easing; var value; var prop; var props = {};

var match;

while((match = rxPropValue.exec(frame.props)) !== null) { prop = match[1]; value = match[2];

easing = prop.match(rxPropEasing);

//Is there an easing specified for this prop? if(easing !== null) { prop = easing[1]; easing = easing[2]; } else { easing = DEFAULT_EASING; }

//Exclamation point at first position forces the value to be taken literal. value = value.indexOf('!') ? _parseProp(value) : [value.slice(1)];

//Save the prop for this key frame with his value and easing function props[prop] = { value: value, easing: easings[easing] }; }

frame.props = props; } };

/** * Parses a value extracting numeric values and generating a format string * for later interpolation of the new values in old string. * * @param val The CSS value to be parsed. * @return Something like ["rgba(?%,?%, ?%,?)", 100, 50, 0, .7] * where the first element is the format string later used * and all following elements are the numeric value. */ var _parseProp = function(val) { var numbers = [];

//One special case, where floats don't work. //We replace all occurences of rgba colors //which don't use percentage notation with the percentage notation. rxRGBAIntegerColor.lastIndex = 0; val = val.replace(rxRGBAIntegerColor, function(rgba) { return rgba.replace(rxNumericValue, function(n) { return n / 255 * 100 + '%'; }); });

//Handle prefixing of "gradient" values. //For now only the prefixed value will be set. Unprefixed isn't supported anyway. if(theDashedCSSPrefix) { rxGradient.lastIndex = 0; val = val.replace(rxGradient, function(s) { return theDashedCSSPrefix + s; }); }

//Now parse ANY number inside this string and create a format string. val = val.replace(rxNumericValue, function(n) { numbers.push(+n); return '{?}'; });

//Add the formatstring as first value. numbers.unshift(val);

return numbers; };

/** * Fills the key frames with missing left and right hand properties. * If key frame 1 has property X and key frame 2 is missing X, * but key frame 3 has X again, then we need to assign X to key frame 2 too. * * @param sk A skrollable. */ var _fillProps = function(sk) { //Will collect the properties key frame by key frame var propList = {}; var keyFrameIndex; var keyFramesLength;

//Iterate over all key frames from left to right keyFrameIndex = 0; keyFramesLength = sk.keyFrames.length;

for(; keyFrameIndex < keyFramesLength; keyFrameIndex++) { _fillPropForFrame(sk.keyFrames[keyFrameIndex], propList); }

//Now do the same from right to fill the last gaps

propList = {};

//Iterate over all key frames from right to left keyFrameIndex = sk.keyFrames.length - 1;

for(; keyFrameIndex >= 0; keyFrameIndex--) { _fillPropForFrame(sk.keyFrames[keyFrameIndex], propList); } };

var _fillPropForFrame = function(frame, propList) { var key;

//For each key frame iterate over all right hand properties and assign them, //but only if the current key frame doesn't have the property by itself for(key in propList) { //The current frame misses this property, so assign it. if(!hasProp.call(frame.props, key)) { frame.props[key] = propList[key]; } }

//Iterate over all props of the current frame and collect them for(key in frame.props) { propList[key] = frame.props[key]; } };

/** * Calculates the new values for two given values array. */ var _calcInterpolation = function(val1, val2, progress) { var valueIndex; var val1Length = val1.length;

//They both need to have the same length if(val1Length !== val2.length) { throw 'Can\'t interpolate between "' + val1[0] + '" and "' + val2[0] + '"'; }

//Add the format string as first element. var interpolated = [val1[0]];

valueIndex = 1;

for(; valueIndex < val1Length; valueIndex++) { //That's the line where the two numbers are actually interpolated. interpolated[valueIndex] = val1[valueIndex] + ((val2[valueIndex] - val1[valueIndex]) * progress); }

return interpolated; };

/** * Interpolates the numeric values into the format string. */ var _interpolateString = function(val) { var valueIndex = 1;

rxInterpolateString.lastIndex = 0;

return val[0].replace(rxInterpolateString, function() { return val[valueIndex++]; }); };

/** * Resets the class and style attribute to what it was before skrollr manipulated the element. * Also remembers the values it had before reseting, in order to undo the reset. */ var _reset = function(elements, undo) { //We accept a single element or an array of elements. elements = [].concat(elements);

var skrollable; var element; var elementsIndex = 0; var elementsLength = elements.length;

for(; elementsIndex < elementsLength; elementsIndex++) { element = elements[elementsIndex]; skrollable = _skrollables[element[SKROLLABLE_ID_DOM_PROPERTY]];

//Couldn't find the skrollable for this DOM element. if(!skrollable) { continue; }

if(undo) { //Reset class and style to the "dirty" (set by skrollr) values. element.style.cssText = skrollable.dirtyStyleAttr; _updateClass(element, skrollable.dirtyClassAttr); } else { //Remember the "dirty" (set by skrollr) class and style. skrollable.dirtyStyleAttr = element.style.cssText; skrollable.dirtyClassAttr = _getClass(element);

//Reset class and style to what it originally was. element.style.cssText = skrollable.styleAttr; _updateClass(element, skrollable.classAttr); } } };

/** * Detects support for 3d transforms by applying it to the skrollr-body. */ var _detect3DTransforms = function() { _translateZ = 'translateZ(0)'; skrollr.setStyle(_skrollrBody, 'transform', _translateZ);

var computedStyle = getStyle(_skrollrBody); var computedTransform = computedStyle.getPropertyValue('transform'); var computedTransformWithPrefix = computedStyle.getPropertyValue(theDashedCSSPrefix + 'transform'); var has3D = (computedTransform && computedTransform !== 'none') || (computedTransformWithPrefix && computedTransformWithPrefix !== 'none');

if(!has3D) { _translateZ = ; } };

/** * Set the CSS property on the given element. Sets prefixed properties as well. */ skrollr.setStyle = function(el, prop, val) { var style = el.style;

//Camel case. prop = prop.replace(rxCamelCase, rxCamelCaseFn).replace('-', );

//Make sure z-index gets a <integer>. //This is the only <integer> case we need to handle. if(prop === 'zIndex') { if(isNaN(val)) { //If it's not a number, don't touch it. //It could for example be "auto" (#351). style[prop] = val; } else { //Floor the number. style[prop] = + (val | 0); } } //#64: "float" can't be set across browsers. Needs to use "cssFloat" for all except IE. else if(prop === 'float') { style.styleFloat = style.cssFloat = val; } else { //Need try-catch for old IE. try { //Set prefixed property if there's a prefix. if(theCSSPrefix) { style[theCSSPrefix + prop.slice(0,1).toUpperCase() + prop.slice(1)] = val; }

//Set unprefixed. style[prop] = val; } catch(ignore) {} } };

/** * Cross browser event handling. */ var _addEvent = skrollr.addEvent = function(element, names, callback) { var intermediate = function(e) { //Normalize IE event stuff. e = e || window.event;

if(!e.target) { e.target = e.srcElement; }

if(!e.preventDefault) { e.preventDefault = function() { e.returnValue = false; }; }

return callback.call(this, e); };

names = names.split(' ');

var name; var nameCounter = 0; var namesLength = names.length;

for(; nameCounter < namesLength; nameCounter++) { name = names[nameCounter];

if(element.addEventListener) { element.addEventListener(name, callback, false); } else { element.attachEvent('on' + name, intermediate); }

//Remember the events to be able to flush them later. _registeredEvents.push({ element: element, name: name, listener: callback }); } };

var _removeEvent = skrollr.removeEvent = function(element, names, callback) { names = names.split(' ');

var nameCounter = 0; var namesLength = names.length;

for(; nameCounter < namesLength; nameCounter++) { if(element.removeEventListener) { element.removeEventListener(names[nameCounter], callback, false); } else { element.detachEvent('on' + names[nameCounter], callback); } } };

var _removeAllEvents = function() { var eventData; var eventCounter = 0; var eventsLength = _registeredEvents.length;

for(; eventCounter < eventsLength; eventCounter++) { eventData = _registeredEvents[eventCounter];

_removeEvent(eventData.element, eventData.name, eventData.listener); }

_registeredEvents = []; };

var _reflow = function() { var pos = _instance.getScrollTop();

//Will be recalculated by _updateDependentKeyFrames. _maxKeyFrame = 0;

if(_forceHeight && !_isMobile) { //un-"force" the height to not mess with the calculations in _updateDependentKeyFrames (#216). body.style.height = 'auto'; }

_updateDependentKeyFrames();

if(_forceHeight && !_isMobile) { //"force" the height. body.style.height = (_maxKeyFrame + documentElement.clientHeight) + 'px'; }

//The scroll offset may now be larger than needed (on desktop the browser/os prevents scrolling farther than the bottom). if(_isMobile) { _instance.setScrollTop(Math.min(_instance.getScrollTop(), _maxKeyFrame)); } else { //Remember and reset the scroll pos (#217). _instance.setScrollTop(pos, true); }

_forceRender = true; };

/* * Returns a copy of the constants object where all functions and strings have been evaluated. */ var _processConstants = function() { var viewportHeight = documentElement.clientHeight; var copy = {}; var prop; var value;

for(prop in _constants) { value = _constants[prop];

if(typeof value === 'function') { value = value.call(_instance); } //Percentage offset. else if((/p$/).test(value)) { value = (value.slice(0, -1) / 100) * viewportHeight; }

copy[prop] = value; }

return copy; };

/* * Returns the height of the document. */ var _getDocumentHeight = function() { var skrollrBodyHeight = (_skrollrBody && _skrollrBody.offsetHeight || 0); var bodyHeight = Math.max(skrollrBodyHeight, body.scrollHeight, body.offsetHeight, documentElement.scrollHeight, documentElement.offsetHeight, documentElement.clientHeight);

return bodyHeight - documentElement.clientHeight; };

/** * Returns a string of space separated classnames for the current element. * Works with SVG as well. */ var _getClass = function(element) { var prop = 'className';

//SVG support by using className.baseVal instead of just className. if(window.SVGElement && element instanceof window.SVGElement) { element = element[prop]; prop = 'baseVal'; }

return element[prop]; };

/** * Adds and removes a CSS classes. * Works with SVG as well. * add and remove are arrays of strings, * or if remove is ommited add is a string and overwrites all classes. */ var _updateClass = function(element, add, remove) { var prop = 'className';

//SVG support by using className.baseVal instead of just className. if(window.SVGElement && element instanceof window.SVGElement) { element = element[prop]; prop = 'baseVal'; }

//When remove is ommited, we want to overwrite/set the classes. if(remove === undefined) { element[prop] = add; return; }

//Cache current classes. We will work on a string before passing back to DOM. var val = element[prop];

//All classes to be removed. var classRemoveIndex = 0; var removeLength = remove.length;

for(; classRemoveIndex < removeLength; classRemoveIndex++) { val = _untrim(val).replace(_untrim(remove[classRemoveIndex]), ' '); }

val = _trim(val);

//All classes to be added. var classAddIndex = 0; var addLength = add.length;

for(; classAddIndex < addLength; classAddIndex++) { //Only add if el not already has class. if(_untrim(val).indexOf(_untrim(add[classAddIndex])) === -1) { val += ' ' + add[classAddIndex]; } }

element[prop] = _trim(val); };

var _trim = function(a) { return a.replace(rxTrim, ); };

/** * Adds a space before and after the string. */ var _untrim = function(a) { return ' ' + a + ' '; };

var _now = Date.now || function() { return +new Date(); };

var _keyFrameComparator = function(a, b) { return a.frame - b.frame; };

/* * Private variables. */

//Singleton var _instance;

/* A list of all elements which should be animated associated with their the metadata. Exmaple skrollable with two key frames animating from 100px width to 20px:

skrollable = { element: <the DOM element>, styleAttr: <style attribute of the element before skrollr>, classAttr: <class attribute of the element before skrollr>, keyFrames: [ { frame: 100, props: { width: { value: ['{?}px', 100], easing: <reference to easing function> } }, mode: "absolute" }, { frame: 200, props: { width: { value: ['{?}px', 20], easing: <reference to easing function> } }, mode: "absolute" } ] }; */ var _skrollables;

var _skrollrBody;

var _listeners; var _forceHeight; var _maxKeyFrame = 0;

var _scale = 1; var _constants;

var _mobileDeceleration;

//Current direction (up/down). var _direction = 'down';

//The last top offset value. Needed to determine direction. var _lastTop = -1;

//The last time we called the render method (doesn't mean we rendered!). var _lastRenderCall = _now();

//For detecting if it actually resized (#271). var _lastViewportWidth = 0; var _lastViewportHeight = 0;

var _requestReflow = false;

//Will contain data about a running scrollbar animation, if any. var _scrollAnimation;

var _smoothScrollingEnabled;

var _smoothScrollingDuration;

//Will contain settins for smooth scrolling if enabled. var _smoothScrolling;

//Can be set by any operation/event to force rendering even if the scrollbar didn't move. var _forceRender;

//Each skrollable gets an unique ID incremented for each skrollable. //The ID is the index in the _skrollables array. var _skrollableIdCounter = 0;

var _edgeStrategy;

//Mobile specific vars. Will be stripped by UglifyJS when not in use. var _isMobile = false;

//The virtual scroll offset when using mobile scrolling. var _mobileOffset = 0;

//If the browser supports 3d transforms, this will be filled with 'translateZ(0)' (empty string otherwise). var _translateZ;

//Will contain data about registered events by skrollr. var _registeredEvents = [];

//Animation frame id returned by RequestAnimationFrame (or timeout when RAF is not supported). var _animFrame; }(window, document));