screen resolution and virtual desktop size

[Tomas Carnecky]

FYI, the nvidia blob supports what I had requested. You can select
amongst these 'GPU Scaling' methods:
 - Stretched
 - Centered
 - Aspect Ratio Scaled

The last method is what I requested, and it works perfectly. In
nvidia-settings (which is used to configure it) you can also see all the
resolutions that are used to drive the display:
 - Native resolution
 - Best Fit Resolution
 - Frontend Resolution
 - Backend Resolution

A tooltip describes what they mean and you can nicely see how they
change if you change the resolution and scaling method.

cheers
tom