i dont know if this what you or not but
at top left corner
click project > project setting > general
then scroll down find Display > window
at bottom you find strech > aspect
you can take choice expand or keep hight/width or keep both.
if you take expand sometime pixel become blur or not match, but if take keep, will keep you pixel but sometime have blank both side. not sure how to explain . you can tried it.
sorry for my broken eng