The getImageData function

The getImageData function allows to retrieve an ImageData object from your canvas. This allows you to manipulate it as you wish and then you can add it back onto the canvas with the putImageData function (reference page for the putImageData function). You can pass it the X/Y/W/H that you want to fetch as arguments.

Arguments to the function

An example

    window.onload = function ()
        var canvas = document.getElementById('cvs');
        var context = canvas.getContext('2d');
        // Fetches image data from the canvas
        var imgData = context.getImageData(0,0,600,250);

See also