| 提交 | 用户 | age | ||
| 2a61f6 | 1 | Math.easeInOutQuad = function(t, b, c, d) { |
| L | 2 | t /= d / 2 |
| 3 | if (t < 1) { | |
| 4 | return c / 2 * t * t + b | |
| 5 | } | |
| 6 | t-- | |
| 7 | return -c / 2 * (t * (t - 2) - 1) + b | |
| 8 | } | |
| 9 | ||
| 10 | // requestAnimationFrame for Smart Animating http://goo.gl/sx5sts | |
| 11 | var requestAnimFrame = (function() { | |
| 12 | return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || function(callback) { window.setTimeout(callback, 1000 / 60) } | |
| 13 | })() | |
| 14 | ||
| 15 | /** | |
| 16 | * Because it's so fucking difficult to detect the scrolling element, just move them all | |
| 17 | * @param {number} amount | |
| 18 | */ | |
| 19 | function move(amount) { | |
| 20 | document.documentElement.scrollTop = amount | |
| 21 | document.body.parentNode.scrollTop = amount | |
| 22 | document.body.scrollTop = amount | |
| 23 | } | |
| 24 | ||
| 25 | function position() { | |
| 26 | return document.documentElement.scrollTop || document.body.parentNode.scrollTop || document.body.scrollTop | |
| 27 | } | |
| 28 | ||
| 29 | /** | |
| 30 | * @param {number} to | |
| 31 | * @param {number} duration | |
| 32 | * @param {Function} callback | |
| 33 | */ | |
| 34 | export function scrollTo(to, duration, callback) { | |
| 35 | const start = position() | |
| 36 | const change = to - start | |
| 37 | const increment = 20 | |
| 38 | let currentTime = 0 | |
| 39 | duration = (typeof (duration) === 'undefined') ? 500 : duration | |
| 40 | var animateScroll = function() { | |
| 41 | // increment the time | |
| 42 | currentTime += increment | |
| 43 | // find the value with the quadratic in-out easing function | |
| 44 | var val = Math.easeInOutQuad(currentTime, start, change, duration) | |
| 45 | // move the document.body | |
| 46 | move(val) | |
| 47 | // do the animation unless its over | |
| 48 | if (currentTime < duration) { | |
| 49 | requestAnimFrame(animateScroll) | |
| 50 | } else { | |
| 51 | if (callback && typeof (callback) === 'function') { | |
| 52 | // the animation is done so lets callback | |
| 53 | callback() | |
| 54 | } | |
| 55 | } | |
| 56 | } | |
| 57 | animateScroll() | |
| 58 | } | |
