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quadruple pixels in xorg

Posted: Fri Mar 01, 2013 1:44 am
by kmieciu
Stupid question early in the morning. Is it possible to quadruple pixels using only xorg settings? I have a panel with native resolution of 1280x1024. I want to run xorg at quarter of that, 640x512, but with each pixel rendered as four pixels so the panel stays at its native resolution. Is it possible to get this using xorg settings - combination of dpi, display size or something? The panel itself does not support 640x512 - I wonder why, it supports a lot of other resolutions and scaling by 2 in each dimension should be easier than scaling by some fraction.

Re: quadruple pixels in xorg

Posted: Fri Mar 01, 2013 8:26 am
by notfred
What drivers and hardware is this on? The nvidia driver in the GUI settings tool has a "Force Full GPU Scaling" option that I think does what you want.

Re: quadruple pixels in xorg

Posted: Fri Mar 01, 2013 12:23 pm
by kmieciu
I have nvidia drivers v304.64 and the drivers control panel does not allow such configuration. It does not even have option to force GPU scaling anymore.

Re: quadruple pixels in xorg

Posted: Sun Mar 03, 2013 5:00 pm
by Flatland_Spider
It's not possible. The Xorg windowing system isn't built to support resolution independent of the native resolution of the monitor. OS X's windowing system comes the closest to being able to do that.

Re: quadruple pixels in xorg

Posted: Sun Mar 03, 2013 5:09 pm
by chuckula
Flatland_Spider wrote:
It's not possible. The Xorg windowing system isn't built to support resolution independent of the native resolution of the monitor. OS X's windowing system comes the closest to being able to do that.


I'm not sure I agree with that statement completely... back in the day when you had CRT displays it was perfectly possible to have different X output resolutions. On top of that you had the panned desktop output thing which was ugly but moderately workable.

OK: I just ran nvidia-settings and was able to get my 1920x1200 native desktop down to 1280x1024 and a bunch of other intermediate resolutions. It's a little ugly due to being non-native resolution, but it works. Is there some other setting you are talking about that doesn't work?

Re: quadruple pixels in xorg

Posted: Sun Mar 03, 2013 11:02 pm
by Flatland_Spider
chuckula wrote:
I'm not sure I agree with that statement completely... back in the day when you had CRT displays it was perfectly possible to have different X output resolutions. On top of that you had the panned desktop output thing which was ugly but moderately workable.

OK: I just ran nvidia-settings and was able to get my 1920x1200 native desktop down to 1280x1024 and a bunch of other intermediate resolutions. It's a little ugly due to being non-native resolution, but it works. Is there some other setting you are talking about that doesn't work?


That reply was badly worded and unclear.

It's still perfectly possible to have X output different resolutions. It's dependent on the monitor to support the resolutions though.

I remember the desktop panning feature. It was pretty cool. I'm not sure X still has that ability, but I've been meaning to find out.

The OP wants Xorg to scale the output to 640x512 while actually outputting 1280x1024, which is the native resolution of the monitor. This is not possible. Xorg will output 640x512, but it's not going to simulate 640x512 while actually outputting 1280x1024.

Re: quadruple pixels in xorg

Posted: Thu Apr 18, 2013 1:21 pm
by bhtooefr
xrandr --output VGA --mode 1280x1024 --panning 640x512 --scale 0.5x0.5


Worth a shot. (Use the actual output, instead of VGA, if it's not VGA or it doesn't do anything.)

Re: quadruple pixels in xorg

Posted: Sun Apr 21, 2013 4:33 am
by jihadjoe
Scaling via Viewportin/Viewportout should make this possible:

Option "metamodes" "CRT-0: 640x512 { ViewPortOut=1280x1024, ViewPortIn=640x512 }"

(replace CRT-0 with your display device id)

Basicaly tells X that when it gets a 640x512 video mode, it should scale the output to 1280x1024


Reference: http://us.download.nvidia.com/XFree86/L ... tions.html