Using transform to center a div along with animation [duplicate] - html

Question

This question already has an answer here:
How to keep origin in center of image in scale animation?
(1 answer)
Closed 1 year ago.
So I'm trying to implement a loader that spins in the middle of the screen I have used transform:translate earlier do this ex:
position: absolute;
left:50%;
top:50%;
transform: translate(-50%,-50%);
I tried to implement something similar but instead of getting centered the top left appears to be in the center. Here's my code
HTML
<section class="waitwrapper" v-else>
<div class="loader"></div>
</section>
CSS
.waitwrapper{
background-color: #455879;
position: relative;
width: 98vw;
height: 97vh;
}
.loader{
border: 16px solid #f3f3f3;
border-top: 16px solid #455879; /* w3schools loader */
border-radius: 50%;
width: 20%;
aspect-ratio:1;
animation: spin 2s linear infinite;
position: absolute;
left:50%;
top:50%;
transform: translate(-50%,-50%);
}
#keyframes spin {
0% { transform: rotate(0deg); }
100% { transform: rotate(360deg); }
}

Answer 1

One trusted way to centralize one item is to use display: flex with justify-content: center and align-items: center in the parent element.
*, *::before, *::after{
box-sizing:border-box;
}
.waitwrapper{
background-color: #455879;
width: 98vw;
height: 97vh;
display:flex;
justify-content:center;
align-items:center
}
.loader{
border: 16px solid #f3f3f3;
border-top: 16px solid #455879; /* w3schools loader */
border-radius: 50%;
width: 20%;
aspect-ratio:1;
animation: spin 2s linear infinite;
}
#keyframes spin {
0% { transform: rotate(0deg); }
100% { transform: rotate(360deg); }
}
<section class="waitwrapper" v-else>
<div class="loader"></div>
</section>
But why your code doesn't work very well? I must tell you when you change transform property in your animation actually you overwrite it. And because of it transform: translate(-50%, -50%);, doesn't work enymore. For solve that problem you can use below solution
.waitwrapper{
background-color: #455879;
position: relative;
width: 98vw;
height: 97vh;
}
.loader{
border: 16px solid #f3f3f3;
border-top: 16px solid #455879; /* w3schools loader */
border-radius: 50%;
width: 20%;
aspect-ratio:1;
animation: spin 2s linear infinite;
position: absolute;
left:50%;
top:50%;
/* transform:translate(-50%,-50%); */
}
#keyframes spin {
0%{
transform: translate(-50%, -50%) rotate(0deg);
}
100% {
transform: translate(-50%, -50%) rotate(360deg);
}
}
<section class="waitwrapper" v-else>
<div class="loader"></div>
</section>

Answer 2

Don't use transform. Use display: flex; on the parent and margin: auto; on the spinner element — to center it both horizontally and vertically.
See the code comments for the needed changes:
/* Quick reset */ * {margin: 0; box-sizing: border-box; }
.loader-wrapper {
background-color: #455879;
position: fixed; /* why relative? use fixed! Should cover the page? */
z-index: 9999; /* overlay other elements */
width: 100vw;
height: 100vh;
display: flex; /* use display flex */
}
.loader {
height: 20%; /* use height instead of width */
aspect-ratio: 1;
margin: auto; /* center inside the flex parent */
border: 10px solid #f3f3f3;
border-top-color: transparent; /* use transparent instead */
border-radius: 50%;
animation: spin 2s linear infinite;
}
#keyframes spin {
to { transform: rotate(1turn); }
}
<section class="loader-wrapper">
<div class="loader"></div>
</section>

Answer 3

Here is one of the ways how to center position-absolute element with width set:
position: absolute;
margin-left: auto;
margin-right: auto;
margin-top: auto;
margin-bottom: auto;
left: 0;
right: 0;
top:0;
bottom:0;
width:20%;
Complete snippet:
.waitwrapper{
background-color: #455879;
position: relative;
width: 98vw;
height: 97vh;
}
.loader{
border: 16px solid #f3f3f3;
border-top: 16px solid #455879; /* w3schools loader */
border-radius: 50%;
aspect-ratio:1;
animation: spin 2s linear infinite;
position: absolute;
margin-left: auto;
margin-right: auto;
margin-top: auto;
margin-bottom: auto;
left: 0;
right: 0;
top:0;
bottom:0;
width:20%;
}
#keyframes spin {
0% { transform: rotate(0deg); }
100% { transform: rotate(360deg); }
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<section class="waitwrapper" v-else>
<div class="loader"></div>
</section>
</body>
</html>