Can I set different DPI for two displays in my system?

[Łukasz Maśko]

Hello.
I have a laptop with 12.5" display and FullHD resolution, which means 176dpi 
density. I also use, in parallel, another FullHD 21.5" monitor, giving me 
almost half of the density as on the main screen. You can easily imagine, that 
since DPI is set the same for both screens, the window moved from one screen 
to another changes its physical size, which is pretty logical - although a bit 
annoying.

Is it possible to configure X in such way, that each screen would work 
according to its own, real physical DPI?

I know I can obtain an approximation of the thing I'm talking about if I set 
the frambuffer to around 4800x1800 and scale the output to the exterlan 
monitor twice:
$ xrandr --fb 4800x1800 --output DP1-3 --scale-from 2880x1800 --output eDP1 --
pos 2880x0
But it looks awfull and is not usable.

PS. My laptop has Intel(R) HD graphics 5500.
-- 
Łukasz Maśko                                                            _o)
Lukasz.Masko(at)ipipan.waw.pl                                           /\\
Registered Linux User #61028                                           _\_V
Ubuntu: staroafrykańskie słowo oznaczające "Nie umiem zainstalować Debiana"