Actually the correct way to copy the canvas data is to pass the old canvas to the new blank canvas. Try this function.

function cloneCanvas(oldCanvas) {



    //create a new canvas

    var newCanvas = document.createElement('canvas');

    var context = newCanvas.getContext('2d');



    //set dimensions

    newCanvas.width = oldCanvas.width;

    newCanvas.height = oldCanvas.height;



    //apply the old canvas to the new one

    context.drawImage(oldCanvas, 0, 0);



    //return the new canvas

    return newCanvas;

}

Using getImageData is for pixel data access, not for copying canvases. Copying with it is very slow and hard on the browser. It should be avoided.