I pick up on this question. What I have so far:
$('.lock').click(function () {
$('.fa-lock', this).addClass('fa-flip');
$('.fa-unlock', this).addClass('fa-flip');
setTimeout(function () {
$('.fa-lock').css('color', 'rgba(0, 0, 0, 0)');
$('.fa-unlock').css('color', 'green');
}, 1250);
});<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.0.0-beta2/js/all.min.js"></script>
<link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.0.0-beta2/css/all.min.css" rel="stylesheet"/>
<div class="fa-5x fa-stack lock">
<i class="fas fa-unlock fa-stack-1x" style="--fa-animation-duration: 5s; --fa-animation-iteration-count: 1; color: rgba(0, 0, 0, 0)"></i>
<i class="fas fa-lock fa-stack-1x" style="--fa-animation-duration: 5s; --fa-animation-iteration-count: 1; color: red"></i>
</div>But only the last quarter of the green unlock icon animation should follow the visible red lock icon animation. How can I start the animation at 75 %?
Or would you do it all differently? Maybe without Font Awesome's animation functions?
You need to override .fa-flip animation:
$('.lock').click(function() {
$('.fa-lock', this).addClass('fa-flip');
$('.fa-unlock', this).addClass('fa-flip');
setTimeout(function() {
$('.fa-lock').css('color', 'rgba(0, 0, 0, 0)');
$('.fa-unlock').css('color', 'green');
}, 600);
});<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.0.0-beta2/js/all.min.js"></script>
<link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.0.0-beta2/css/all.min.css" rel="stylesheet" />
<style>
@keyframes halfflip {
to {
transform: rotateY(360deg);
}
}
.fa-flip {
animation-name: halfflip;
animation-timing-function: ease-in-out;
}
</style>
<div class="fa-5x fa-stack lock">
<i class="fas fa-unlock fa-stack-1x" style="--fa-animation-duration: 4s; --fa-animation-iteration-count: 1; color: transparent; animation-fill-mode: forwards; --fa-animation-delay:-2s"></i>
<i class="fas fa-lock fa-stack-1x" style="--fa-animation-duration: 4s; --fa-animation-iteration-count: 1; color: red; animation-fill-mode: forwards; --fa-animation-delay:-2s"></i>
</div>
I hope this is what you wanted.