CSS change animation duration without jumping

Question

I have a simple animation of a wheel spinning. I am trying to control the speed of the spinning wheel using a slider (input range). I have managed to do this, but every time I change the animation the animation restarts (it jumps). Looking for a solution to create a smooth increase of the speed. As the user increases the value of the slider, the wheel rotates with an increased speed.

In the code below, #loading is the spinning wheel.

$(document).on('input', '#slider', function() {
  var speed = $(this).val();
  $('#speed').html(speed);
  $("#loading").css("animation-duration", 50 / speed + "s");
});

#loading {
  position: absolute;
  width:100px; height:100px; background-color:black;
  left: 0;
  right: 0;
  margin: auto;
  transform-origin: 50% 50%;
  animation: rotateRight infinite linear;
  animation-duration: 0;
}

@keyframes rotateRight {
  100% {
    transform: rotate(360deg);
  }
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<div id="loading"></div>
<input type="range" min="0" max="100" value="0" class="slider" id="slider">
<p>Speed: <span id="speed"></span></p>

Answer 1

Classic Question
(with jumping.. now yet )

Version with jQuery

var lasttime = 0,  lastduration = 0,  angle = 0;
$(document).on('input', '#slider', function(event) {
  var speed = $(this).val();
  $('#speed').html(speed);
  
  var el = $("#loading");
  var duration = (speed > 0) ? 50 / speed : 0;
  var currenttime = event.originalEvent.timeStamp / 1000;
  var difftime = currenttime - lasttime;
  el.removeClass("enable_rotate").show();
  
  if (!lastduration && duration)
      el.css("transform", "");
  else
      angle += (difftime % lastduration) / lastduration;
      
  if (duration){     
    el.css("animation-duration", duration + "s")
    .css("animation-delay", -duration * angle + "s")    
    .addClass("enable_rotate");
    }
  else
    el.css("transform", "rotate(" + 360 * angle + "deg)");
  
  angle -= angle | 0; //use fractional part only
  lasttime = currenttime;
  lastduration = duration;
});

.anime_object {
  width:100px; height:100px; background-color:black;
  position: absolute;
  left: 0;
  right: 0;
  margin: auto;
}

.enable_rotate {
  animation: rotateRight infinite linear;
}

@keyframes rotateRight {
  100% {
    transform: rotate(360deg);
  }
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<img id="loading" class="anime_object">
<input type="range" min="0" max="100" value="0" id="slider">
<p>Speed: <span id="speed"></span></p>

Work draft

save variable of currentanimation
http://www.w3.org/TR/css-animations-1/#interface-animationevent-attributes

1. SO
2. css-tricks.com