Choppy transition: transform scalling animation on Safari - css

Question

I have hard time making scaling animation that is not choppy in Safari (mobile). By choppy I mean you can clearly see that it's not 60FPS fluid animation. I need to say that element is absolutely positioned so it should not affect layout, should it?
First thing that I tried is animating element by creating CSS animation with 2 keyframes, going from transform: scale(0); to transform: scale(1);. For the effect I want to achieve I also used transform-origin: top right;. I also tried to optimize it by setting will-change: transform; but it was choppy.
I scrapped it and reworked it so it uses transition: transform. So by default element has transform: scale(0);, when certain class attaches to it, it gets transform: scale(1); which transition is animating, but it is still choppy.
After some research I found out that you want to avoid animating properties that require browsers to recalculate layout. I found out this site which says that WebKit (which Safari is using as far as I know) pretty much recalculates layout for every property change. Is that true, and if it is how do you make 60FPS fluid animations on mobile Safari (on other platforms using Safari it's not that noticeable because they have much more resources to recalculate everything and it appears a bit smoother than on mobile)?

Answer 1

There are 2 things that you can try:
avoid using scale(0). In some browsers this gives problems. scale(0.01) is almost the same, and will be better for the browser.
Try to make the animation handled by the GPU instead of the CPU. this can be done with the following code
from: {transform: scale(0.01) translateZ(1px);}
to: {transform: scale(1) translateZ(1px);}

Answer 2

In reference to this article section Animate Changes in CSS Properties, you can animate with keyframes, but need use a percentage like this:
More examples in w3s article.
PD: if you add an example, i'll try to help you.
function animateStart(){
document.getElementById('ball').classList.add('bounce');
}
function animationPause(){
document.getElementById('ball').style.webkitAnimationPlayState='paused';
}
function animationContinue(){
document.getElementById('ball').style.webkitAnimationPlayState='running';
}
#-webkit-keyframes bounce {
0% {top: 100px; left: 1px; -webkit-animate-timing-function: ease-in;}
25% {top: 150px; left: 76px; -webkit-animate-timing-function: ease-out;}
50% {top: 100px; left: 151px -webkit-animate-timing-function: ease-in;}
75% {top: 150px; left: 226px -webkit-animate-timing-function: ease-out;}
100% {top:100px; left: 301px;}
}
.bounce {
-webkit-animation-name: bounce;
-webkit-animation-duration: 2s;
-webkit-animation-timing-function: linear;
-webkit-animation-iteration-count: infinite;
-webkit-animation-direction: alternate;
}
.ball-style {
position:absolute; top: 100px; left: 10px;
height:100px; width:100px; border-radius:50px;
background:-webkit-radial-gradient(30% 30%, white, red 10%, black);;
}
.wall {
position:absolute; left: 400px; top: 100px;
height: 150px;
background: black;
}
<input type="button" value="Animate alternative"
onclick="document.getElementById('ball').classList.add('bounce');">
<input type="button" value="Animate" onclick="animateStart()">
<input type="button" value="Pause" onclick="animationPause()">
<input type="button" value="Continue" onclick="animationContinue()">
<div id="ball" class="ball-style"></div>
<div class="wall"> </div>

Answer 3

I don't know if this helps but are you using javascript to add a class and start the animation with the class change?
jQuery for example can cause long depth analysis in the dom when manipulating elements, this is likely to interfere with the performance you need for achieving the desired fps.