Circular impress.js slide layout in Javascript

gistfile1.js

var steps = document.getElementsByClassName("step");

var r = 2000;
for (var i = 0; i < steps.length; i++) {
  var theta = -i/(steps.length-1) * 2 * Math.PI;
  var x = r * Math.cos(theta);
  var y = r * Math.sin(theta);
  var rotation = theta/(2*Math.PI) * 360 - 90;

  steps[i].setAttribute("data-x", Math.round(x).toString());
  steps[i].setAttribute("data-y", Math.round(y).toString());
  steps[i].setAttribute("data-rotate-z", Math.round(rotation).toString());
}

var overview = document.getElementById("overview");
overview.setAttribute("data-x", "0");
overview.setAttribute("data-y", "0");
overview.setAttribute("data-scale", "5");

// Disable click to move to step.
document.addEventListener("click", function() { event.cancelBubble = true; }, true);

impress().init();