[xooorx]

I had trouble getting measurements in pixels working so I set up, for example, a 2 inch by 2 inch canvas and export to PNG at 32 dots per inch. Result: A 64 x 64 pixel PNG. (I verified this 2 minutes ago).

There's a problem though with stroking a full size rectangle on such a canvas, because the stroke is centred on the rectangle sides leaving half the stroke width off the canvas.