create-transition

Create transitions that CSS can't.

Usage no npm install needed!

<script type="module">
  import createTransition from 'https://cdn.skypack.dev/create-transition';
</script>

README

create-transition

Create transition animations that CSS can't.

Demo

https://jiangfengming.github.io/create-transition/examples/

Usage

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>create-transition</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">

    <style>
    body {
      height: 9999px;
      background-image: linear-gradient(to bottom, rgba(255,255,0,0.5), rgba(0,0,255,0.5));
    }

    .fixed {
      position: fixed;
      top: 10px;
      left: 10px;
    }

    .box {
      margin-top: 2000px;
      width: 200px;
      height: 200px;
      background: #FF2F92;
    }
    </style>
  </head>

  <body>
    <div class="fixed">
      <p><input type="text" id="num" value="0"></p>
      <button id="scrollToTop">scroll to top</button>
      <button id="scrollToBottom">scroll to bottom</button>
      <button id="scrollToBox">scroll to box</button>
      <button id="inc">increase</button>
      <button id="dec">decrease</button>
    </div>

    <div class="box"></div>

    <script type="module">
    import { createTransition, easeInOutQuad, easeInOutCubic } from 'https://unpkg.com/create-transition'

    document.getElementById('scrollToTop').addEventListener('click', scrollToTop)
    document.getElementById('scrollToBottom').addEventListener('click', scrollToBottom)

    document.getElementById('scrollToBox').addEventListener('click', () =>
      scrollToElement(document.querySelector('.box'), 150)
    )

    document.getElementById('inc').addEventListener('click', inc)
    document.getElementById('dec').addEventListener('click', dec)


    function scrollToElement(el, offset = 0) {
      const y = window.scrollY
      const d = el.getBoundingClientRect().top - offset
      createTransition(t => window.scrollTo(0, y + t * d), 300, easeInOutQuad)
    }

    function scrollToTop() {
      const y = window.scrollY
      createTransition(t => window.scrollTo(0, y - t * y), 300, easeInOutQuad)
    }

    function scrollToBottom() {
      const y = window.scrollY
      const d = document.documentElement.scrollHeight - window.innerHeight - window.scrollY
      createTransition(t => window.scrollTo(0, y + t * d), 300, easeInOutQuad)
    }

    function inc() {
      const num = document.getElementById('num')
      const n = parseInt(num.value) || 0
      createTransition(t => num.value = n + Math.round(100 * t), 2000, easeInOutCubic)
    }

    function dec() {
      const num = document.getElementById('num')
      const n = parseInt(num.value) || 0
      createTransition(t => num.value = n - Math.round(100 * t), 2000, easeInOutCubic)
    }
    </script>
  </body>
</html>

Import

import { createTransition, easeInOutQuad /* , ...other easing functions */} from 'create-transition'

If you don't need easing functions:

import createTransition from 'create-transition'

APIs

createTransition(animate, duration, easing = linear)

Creates a transition between two states. It uses requestAnimationFrame underneath.

Params:

animate(o)
Function. The animation function to run per frame. o is the eased value computed by easing(t).

duration
Number. The number of milliseconds a transition animation should take to complete.

easing(t)
Function. A mathematical function that describes how fast one-dimensional values change during animations. This lets you vary the animation's speed over the course of its duration. See more about easing functions: <timing-function> and Improved Easing Functions

t: Number. t = (currentTime - startTime) / duration. It represents the percentage of completeness of the transition. It's value is between 0 and 1.

The return value is the eased value of t. 0.0 represents the initial state, and 1.0 represents the final state. Depending on the specific function used, the calculated output can sometimes grow to be greater than 1.0 or smaller than 0.0 during the course of an animation. This causes the animation to go farther than the final state, and then return. For some properties, such as left or right, this creates a kind of "bouncing" effect.

Example easing function:

function easeInQuad(t) {
  return t * t
}

You can create easing functions using bezier-easing.

generateEaseInBack(amount)

Generates an easeInBack function with custom amount.

generateEaseOutBack(amount)

Generates an easeOutBack function with custom amount.

generateEaseInOutBack(amount)

Generates an easeInOutBack function with custom amount.

generateEaseInElastic(amplitude, period)

Generates an easeInElastic function with custom amplitude and period.

generateEaseOutElastic(amplitude, period)

Generates an easeOutElastic function with custom amplitude and period.

generateEaseInOutElastic(amplitude, period)

Generates an easeInOutElastic function with custom amplitude and period.

Preset easing functions

  • linear
  • easeInQuad
  • easeOutQuad
  • easeInOutQuad
  • easeInCubic
  • easeOutCubic
  • easeInOutCubic
  • easeInQuart
  • easeOutQuart
  • easeInOutQuart
  • easeInQuint
  • easeOutQuint
  • easeInOutQuint
  • easeInSine
  • easeOutSine
  • easeInOutSine
  • easeInBack (shortcut of generateEaseInBack(1.7))
  • easeOutBack (shortcut of generateEaseOutBack(1.7))
  • easeInOutBack (shortcut of generateEaseInOutBack(1.7 * 1.525))
  • easeInElastic (shortcut of generateEaseInElastic(1, 0.3))
  • easeOutElastic (shortcut of generateEaseOutElastic(1, 0.3))
  • easeInOutElastic (shortcut of generateEaseInOutElastic(1, 0.3 * 1.5))
  • easeInBounce
  • easeOutBounce
  • easeInOutBounce

Easing functions are collected from:

License

MIT