There is a graphics option in the native client to not “stretch/ shrink the map”

When you choose this option your screen becomes small but a 1:1 ratio to the graphic sprites, these look better because it is pixel perfect.

I propose an option to lock the window size to be integer multiples like 1:2,1:3,1:4, etc rather than some random ratio. This way you will preserve the pixel sprites and reduce blur.