Where can I change the values for "Xdpi" and "Ydpi"?

[Bartier]

Hello All,

There is an "tDpiInfo.apk" on site "http://www.taosoftware.co.jp/en/
android/dpiinfo/" that if you run on your device, this application
shows some parameters like "Xdpi" and "Ydpi" and theirs values. I know
this values come from videos drivers, but I could not find them.
Anybody knows where I can find and change this values?

Thanks a lot,
Regards,
--Bartier