var photo = new Image();
photo.src = "./Ship1.png";
photo.addEventListener('load', eventPhotoLoaded, false);
function drawImage()
{

this.context.drawImage(photo, 0, 0, photo.width,photo.height, 0, 0, photo.width * currentScale,  photo.height* currentScale);
}

theCanvas.addEventListener('click', function(evt) {
var rect = this.theCanvas.getBoundingClientRect();
x = evt.clientX - rect.left;
y = evt.clientY - rect.top;

//newGird is an array of cells containing R,G,B and Alpha values
context.putImageData(newGird, x, y)