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30-seconds-of-code/snippets/mouse-cursor-gradient-tracking.md
atomiks 767b720f10 Init
2018-02-26 00:14:39 +11:00

2.9 KiB

Mouse cursor gradient tracking

A hover effect where the gradient follows the mouse cursor.

HTML

<button class="mouse-cursor-gradient-tracking">
  <span>Hover me</span>
</button>

CSS

.mouse-cursor-gradient-tracking {
  position: relative;
  background: #2379f7;
  padding: 0.5rem 1rem;
  font-size: 1.2rem;
  border: none;
  color: white;
  cursor: pointer;
  outline: none;
  overflow: hidden;
}

.mouse-cursor-gradient-tracking span {
  position: relative;
}

.mouse-cursor-gradient-tracking::before {
  --size: 0;
  content: '';
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: var(--size);
  height: var(--size);
  background: radial-gradient(circle closest-side, pink, transparent);
  transform: translate(-50%, -50%);
  transition: width .2s ease, height .2s ease;
}

.mouse-cursor-gradient-tracking:hover::before {
  --size: 200px;
}

JavaScript

var btn = document.querySelector('.mouse-cursor-gradient-tracking')
btn.onmousemove = function (e) {
  var x = e.pageX - btn.offsetLeft
  var y = e.pageY - btn.offsetTop
  btn.style.setProperty('--x', x + 'px')
  btn.style.setProperty('--y', y + 'px')
}

Demo

Hover me
<style> .snippet-demo__mouse-cursor-gradient-tracking { position: relative; background: #2379f7; padding: 0.5rem 1rem; font-size: 1.2rem; border: none; color: white; cursor: pointer; outline: none; overflow: hidden; } .snippet-demo__mouse-cursor-gradient-tracking span { position: relative; } .snippet-demo__mouse-cursor-gradient-tracking::before { --size: 0; content: ''; position: absolute; left: var(--x); top: var(--y); width: var(--size); height: var(--size); background: radial-gradient(circle closest-side, aqua, rgba(0,255,255,0.0001)); transform: translate(-50%, -50%); transition: width .2s ease, height .2s ease; } .snippet-demo__mouse-cursor-gradient-tracking:hover::before { --size: 200px; } </style> <script> (function () { var btn = document.querySelector('.snippet-demo__mouse-cursor-gradient-tracking') btn.onmousemove = function (e) { var x = e.pageX - btn.offsetLeft - btn.offsetParent.offsetLeft var y = e.pageY - btn.offsetTop - btn.offsetParent.offsetTop btn.style.setProperty('--x', x + 'px') btn.style.setProperty('--y', y + 'px') } })() </script>

Explanation

TODO

Note!

If the element's parent has a positioning context (position: relative), you will need to subtract its offsets as well.

var x = e.pageX - btn.offsetLeft - btn.offsetParent.offsetLeft
var y = e.pageY - btn.offsetTop - btn.offsetParent.offsetTop

Browser support

Requires JavaScript
⚠️ Requires JavaScript.