Why is image stretched vertically on widescreen monitor?

[Stuart Kreitman]

Val:

The X protocol assumes square pixels (1:1) so you should observe some 
degree of squish on any non-square display. Its just that you have a 
side by side comparison of 2 different aspect ratios that accentuates 
the effect.  The DPI setting is for the use of clients that perform 
their own drawing operations.


Stuart Kreitman

Val wrote:
> Hi. I am not sure if this is the right place to post basic user questions, so if not, please direct me to a more suitable list.
> 
> I just tried to set up 2 monitors on my dual monitor NVIDIA card and I am confused with the result. 
> The monitors are:
> 1) 22' 16:10 LCD
> 2) 19' 4:3 CRT
> 
> I am running the LCD at its native res of 1680x1050 and the CRT is at
> 1280x1024. This almost works, save for a subtle issue - the aspect ratio
> on the LCD appears to be incorrect. An image of a perfect circle looks
> like a circle on the CRT, but when dragged to the LCD, I can tell that
> the circle is vertically stretched into an ellipse (y > x). 
> 
> I manually set the DPI to be 100x100. Here is the relevant line from the
> log:
> (**) NVIDIA(0): DPI set to (100, 100); computed from "DPI" X config option
> 
> but it had no effect.
> 
> Here is the device section of my xorg.conf:
> Section "Device"
>     Identifier     "Device0"
>     Driver         "nvidia"
>     VendorName     "NVIDIA Corporation"
>     Option   "UseEdidDpi"   "FALSE"    
>     Option   "DPI"   "100x100"
> 
>     Option "TwinView"
>     Option "ConnectedMonitor"           "DFP-0, CRT-1"
>     Option "HorizSync"          "DFP-0: 30-110; CRT-1: 31-82"
>     Option "VertRefresh"        "DFP-0: 50-150; CRT-1: 55-120"
>     Option "MetaModes"          "DFP-0: 1680x1050, CRT-1: 1280x1024;
>     Option "TwinViewOrientation"        "CRT-1 RightOf DFP-0"
> EndSection
> 
> Can anyone please explain to me why the circle looks stretched on the
> LCD and if it is possible to do anything about it? 
> 
> Thank you.
>