Team:Lethbridge/index js

$(document).ready(function () {

   /*
   Menu bar transparency
   */
   $('#content_wrapper').css({paddingTop: 0});

   $('#menu_bar').css({opacity: 0});

   var window_height = $(window).height();
   $(window).resize(function () {
       window_height = $(window).height();
   });

   $(window).scroll(function () {
       var window_scrollTop = $(window).scrollTop();
       if (window_scrollTop < window_height) {
           var menu_opacity = window_scrollTop / window_height;
           $('#menu_bar').css({opacity: menu_opacity});
       }
       else {
           $('#menu_bar').css({opacity: 1});
       }
   });

   /*
   Earh animation
   */
   var canvas = document.getElementById('earth_population');
   canvas.setAttribute('height', 400);
   canvas.setAttribute('width', 400);
   var context = canvas.getContext('2d');
   context.lineWidth = 10;
   context.strokeStyle = '#ff8000';

   var offset = - 0.5 * Math.PI;
   var tau = 2 * Math.PI;
   
   var timeout = 16.7;
   var increment = 0.000625;
   var start = 0.15;
   var end   = 0.85;
   var scale = start;

   var action = function() {
       context.beginPath();
       context.arc(canvas.width / 2, canvas.height / 2, 195, offset, scale * tau + offset, false);
       context.stroke();
       scale += increment;
       if (scale >= end + increment) {
           scale = start;
           context.clearRect(0, 0, canvas.width, canvas.height);
       }
   };

   setInterval(action, timeout);

});