CSS Rotating Images

Question

In short: I am trying to mimic this slider but with animations, not transitions, so I can have autoplay option: codepen.io/dudleystorey/pen/HrFBx

Explanation: I am work

Answer 1

Here is what you can do, add a class (here anim) to the figure and change the hover rule from

figure:hover img.first { transform: rotateY(180deg);  } 
figure:hover img.second { transform: rotateY(0deg) translateZ(1px);  }

to

figure.anim img.first {
  animation-name: rotateus;
  animation-duration: 1s;
  animation-fill-mode: forwards;
} 
figure.anim img.second { 
  animation-name: rotateus2;
  animation-duration: 1s;
  animation-fill-mode: forwards;
}

I also added a @keyframes rule and change from transition-delay to animation-delay

Updated: Based on a comment I also added some text

Stack snippet

body { margin: 0; background: #121; } 
figure { 
  margin: 0;
  position: relative;
  perspective: 1800px;
  transform-style: preserve-3d;
  max-width: 1000px; 
  padding-bottom: 56.25%; 
}

body::before,
body::after { 
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  background: url(https://s3-us-west-2.amazonaws.com/s.cdpn.io/4273/autumn-face.jpg) no-repeat left top;
  background-size: 100%;
}
body::after { 
  background: url(https://s3-us-west-2.amazonaws.com/s.cdpn.io/4273/julia.jpg) no-repeat left top;
  background-size: 100%;
  animation-name: swapbkg;
  animation-duration: 8s;
  animation-iteration-count: infinite;
}

div { 
  top: 0;
  left: 0;
  position: absolute;
  color: white;
  font-size: 40px;
  opacity: 1;
  z-index: 10;
  transform: translate(10px, 10px);
  animation-duration: 8s;
  animation-iteration-count: infinite;
}
div:nth-of-type(2) { 
  animation-name: swaptext2;
}
div:nth-of-type(1) { 
  animation-name: swaptext1;
}


figure img { 
  top: 0;
  left: 0;
  position: absolute;
  width: 100%;
}

figure.anim img.first {
  animation-name: rotateus2;
  animation-duration: 8s;
  animation-iteration-count: infinite;
} 
figure.anim img.second { 
  animation-name: rotateus;
  animation-duration: 8s;
  animation-iteration-count: infinite;
}

@keyframes rotateus {
  0%, 80%, 100%  {
    transform: rotateY(0deg);
  }
  30%, 50% {
    transform: rotateY(180deg);
  }
} 
@keyframes rotateus2 {
  0%, 80%, 100%  {
    transform: rotateY(-180deg) translateZ(1px);
  }
  30%, 50% {
    transform: rotateY(0deg) translateZ(1px); 
  }  
}
@keyframes swapbkg {
  0%, 39% {
    z-index: -1;
  }
  40%, 80% {
    z-index: -2;
  }
} 
@keyframes swaptext1 {
  0%, 20%, 50%, 100% {
    opacity: 0;
  }
  25%, 45% {
    opacity: 1;
  }
} 
@keyframes swaptext2 {
  0%, 70%, 100% {
    opacity: 0;
  }
  75%, 95% {
    opacity: 1;
  }
} 

figure img:nth-child(1), figure img:nth-child(11) { 
  clip: rect(0px, 100px, 840px, 0px);
  transform-origin: 50px 0px;
}
figure img:nth-child(2), figure img:nth-child(12) {
  clip: rect(0px, 200px, 840px, 100px);
  transform-origin: 150px 0px;
  animation-delay: 100ms;
}
figure img:nth-child(3), figure img:nth-child(13) {
  clip: rect(0px, 300px, 840px, 200px);
  transform-origin: 250px 0px;
  animation-delay: 200ms;  
}
figure img:nth-child(4), figure img:nth-child(14) {
  clip: rect(0px, 400px, 840px, 300px);
  transform-origin: 350px 0px;
  animation-delay: 300ms; 
}
figure img:nth-child(5), figure img:nth-child(15) {
  clip: rect(0px, 500px, 840px, 400px);
  transform-origin: 450px 0px;
  animation-delay: 400ms;
}
figure img:nth-child(6), figure img:nth-child(16) {
  clip: rect(0px, 600px, 840px, 500px);
  transform-origin: 550px 0px;
  animation-delay: 500ms; 
}
figure img:nth-child(7), figure img:nth-child(17) {
  clip: rect(0px, 700px, 840px, 600px);
  transform-origin: 650px 0px;
  animation-delay: 600ms;
}
figure img:nth-child(8), figure img:nth-child(18) {
  clip: rect(0px, 800px, 840px, 700px);
  transform-origin: 750px 0px;
  animation-delay: 700ms;
}
figure img:nth-child(9), figure img:nth-child(19) {
  clip: rect(0px, 900px, 840px, 800px);
  transform-origin: 850px 0px;
  animation-delay: 800ms; 
}
figure img:nth-child(10), figure img:nth-child(20) {
  clip: rect(0px, 1000px, 840px, 900px);
  transform-origin: 950px 0px;
  animation-delay: 900ms;  
}

Here is a text
Here is another text

---

If to keep transition and fire it with a script, change hover rule to this

figure.anim img.first { transform: rotateY(180deg);  } 
figure.anim img.second { transform: rotateY(0deg) translateZ(1px);  }

I also added an event handler, which add the class after page been loaded

Stack snippet

window.addEventListener('load', function() {
  var fig = document.querySelector('figure');
  setTimeout(function () {
    fig.classList.add('anim');
  }, 500)
})

body { margin: 0; background: #121; } 
figure { 
  margin: 0;
  position: relative;
  perspective: 1800px;
  transform-style: preserve-3d;
  max-width: 1000px; 
  padding-bottom: 56.25%; 
}
figure img { 
  top: 0;
  left: 0;
  position: absolute;
  transition: 1s;
  width: 100%;
}
figure img.first { transform: rotateY(0deg); }
figure img.second { transform: rotateY(-180deg) translateZ(1px); }

figure.anim img.first { transform: rotateY(180deg);  } 
figure.anim img.second { transform: rotateY(0deg) translateZ(1px);  }

figure img:nth-child(1), figure img:nth-child(11) { 
  clip: rect(0px, 100px, 840px, 0px);
  transform-origin: 50px 0px;
}
figure img:nth-child(2), figure img:nth-child(12) {
  clip: rect(0px, 200px, 840px, 100px);
  transform-origin: 150px 0px;
  transition-delay: 100ms;
}
figure img:nth-child(3), figure img:nth-child(13) {
  clip: rect(0px, 300px, 840px, 200px);
  transform-origin: 250px 0px;
  transition-delay: 200ms;  
}
figure img:nth-child(4), figure img:nth-child(14) {
  clip: rect(0px, 400px, 840px, 300px);
  transform-origin: 350px 0px;
  transition-delay: 300ms; 
}
figure img:nth-child(5), figure img:nth-child(15) {
  clip: rect(0px, 500px, 840px, 400px);
  transform-origin: 450px 0px;
  transition-delay: 400ms;
}
figure img:nth-child(6), figure img:nth-child(16) {
  clip: rect(0px, 600px, 840px, 500px);
  transform-origin: 550px 0px;
  transition-delay: 500ms; 
}
figure img:nth-child(7), figure img:nth-child(17) {
  clip: rect(0px, 700px, 840px, 600px);
  transform-origin: 650px 0px;
  transition-delay: 600ms;
}
figure img:nth-child(8), figure img:nth-child(18) {
  clip: rect(0px, 800px, 840px, 700px);
  transform-origin: 750px 0px;
  transition-delay: 700ms;
}
figure img:nth-child(9), figure img:nth-child(19) {
  clip: rect(0px, 900px, 840px, 800px);
  transform-origin: 850px 0px;
  transition-delay: 800ms; 
}
figure img:nth-child(10), figure img:nth-child(20) {
  clip: rect(0px, 1000px, 840px, 900px);
  transform-origin: 950px 0px;
  transition-delay: 900ms;  
}