A common mistake then reprecenting pixel positions is to use Integers. This is how we did things back in the 80’s and 90’s, but GPU’s use double and pixel 1.5 actually exist. As the GPU smooth lines it will add shades to make it look as if we have pixels between pixels. If your coordinate system is integers only it will mean that a figure that is moved on screen jump one pixel and look as if it changes a little. So in dealing with graphics – always use double and never round off because the GPU will make use of the decimals.