How to get the screen ratio?


I use the saveBitmap command to take a screenshot of the simulation. I want to take a screenshot of the full “simulation area” (the area within the panels). However, you need to give a width and height to the command. I can approximate the ratie between the height and width of the screen by simply measuring, but this is different everytime the size of the side panels is changed. Is there a way to get the exact ratio of the simulation area of the screen?