HTML5 Canvas - Animations


HTML5 canvas provides necessary methods to draw an image and erase it completely. We can take Javascript help to simulate good animation over a HTML5 canvas.

Following are the two important Javascript methods which would be used to animate an image on a canvas −

Sr.No. Method and Description
1 setInterval(callback, time);

This method repeatedly executes the supplied code after a given time milliseconds.

2 setTimeout(callback, time);

This method executes the supplied code only once after a given time milliseconds.


Following is a simple example which would rotate a small image repeatedly −

      <script type="text/javascript">
         var pattern= new Image();
         function animate(){
            pattern.src = '/html5/images/pattern.jpg';
            setInterval(drawShape, 100);
         function drawShape(){
            // get the canvas element using the DOM
            var canvas = document.getElementById('mycanvas');
            // Make sure we don't execute when canvas isn't supported
            if (canvas.getContext){
               // use getContext to use the canvas for drawing
               var ctx = canvas.getContext('2d');
               ctx.fillStyle = 'rgba(0,0,0,0.4)';
               ctx.strokeStyle = 'rgba(0,153,255,0.4)';
               var time = new Date(); 
               ctx.rotate( ((2*Math.PI)/6)*time.getSeconds() + ( (2*Math.PI)/6000)*time.getMilliseconds() );
            else {
               alert('You need Safari or Firefox 1.5+ to see this demo.');
   <body onload="animate();">
      <canvas id="mycanvas" width="400" height="400"></canvas>

The above example would produce following result −