JavaScript drehen Bild Canvas

function drawRotated(degrees){
    context.clearRect(0,0,canvas.width,canvas.height);
    context.save();
    context.translate(canvas.width/2,canvas.height/2);
    context.rotate(degrees*Math.PI/180);
    context.drawImage(image,-image.width/2,-image.width/2);
    context.restore();
}
Undefined