How to prevent child from rotating with parent during the transition?

September 23, 2024

I’m trying to rotate a parent circle and negate the effect on its children.
I tried to negate the effect by using

transform: translate(-50%, -50%)
           rotate(calc(var(--i) * -60deg))
           translateY(150px)
           rotate(calc(var(--i) * 60deg - var(--rotation)))

but the children will rotate 60deg at the start of the transition. How to prevent them from rotating completely duration the transition?

const circle = document.getElementById('circle');
let deg = 0;

function rotate() {
  deg += 60;
  circle.style.cssText = `--rotation: ${deg}deg`;
}

.circle {
  border: 2px solid #ccc;
  border-radius: 50%;
  height: 300px;
  margin: 40px auto 0;
  transform: rotate(var(--rotation));
  transition: transform 1000ms ease;
  position: relative;
  width: 300px;
}

.item {
  align-items: center;
  background: red;
  border: 2px solid #fff;
  border-radius: 50%;
  display: flex;
  height: 30px;
  justify-content: center;
  left: 50%;
  position: absolute;
  top: 50%;
  transform: translate(-50%, -50%) rotate(calc(var(--i) * -60deg)) translateY(150px) rotate(calc(var(--i) * 60deg - var(--rotation)));
  width: 30px;
}

.btn {
  align-items: center;
  background: lawngreen;
  display: flex;
  height: 30px;
  justify-content: center;
  width: 100px;
}

<meta name="viewport" content="width=device-width, initial-scale=1.0">

<div class="circle" id="circle" style="--rotation: 0deg">
  <div class="item" style="--i: 0">1</div>
  <div class="item" style="--i: 1">2</div>
  <div class="item" style="--i: 2">3</div>
  <div class="item" style="--i: 3">4</div>
  <div class="item" style="--i: 4">5</div>
  <div class="item" style="--i: 5">6</div>
</div>

<div class='btn' onclick="rotate()">rotate</div>

>Solution :

You are almost there, simply add the same transition to the child elements

const circle = document.getElementById('circle');
let deg = 0;

function rotate() {
  deg += 60;
  circle.style.cssText = `--rotation: ${deg}deg`;
}

.circle {
  border: 2px solid #ccc;
  border-radius: 50%;
  height: 300px;
  margin: 40px auto 0;
  transform: rotate(var(--rotation));
  transition: transform 1000ms ease;
  position: relative;
  width: 300px;
}

.item {
  align-items: center;
  background: red;
  border: 2px solid #fff;
  border-radius: 50%;
  display: flex;
  height: 30px;
  justify-content: center;
  left: 50%;
  position: absolute;
  top: 50%;
  transform: translate(-50%, -50%) rotate(calc(var(--i) * -60deg)) translateY(150px) rotate(calc(var(--i) * 60deg - var(--rotation)));
  transition: transform 1000ms ease;
  width: 30px;
}

.btn {
  align-items: center;
  background: lawngreen;
  display: flex;
  height: 30px;
  justify-content: center;
  width: 100px;
}

<div class="circle" id="circle" style="--rotation: 0deg">
  <div class="item" style="--i: 0">1</div>
  <div class="item" style="--i: 1">2</div>
  <div class="item" style="--i: 2">3</div>
  <div class="item" style="--i: 3">4</div>
  <div class="item" style="--i: 4">5</div>
  <div class="item" style="--i: 5">6</div>
</div>

<div class='btn' onclick="rotate()">rotate</div>