Draw the image rotated 90 degrees. Because we rotate around the
origin we will lose the image off the edge of our canvas unless we
are careful. We could translate the image back onto the canvas but
to do this we would need to know the size of the image. The easiest
thing to do is to pin the top left of the bounds of the rotated
image to the origin.
canvas.DrawFile inpath, "rotate=90 pin=0,0"