[Rd] X11 device distortion (PR#10666)

[marc_schwartz at comcast.net]

Just to follow up, largely in synch with the two replies already, it
sounds like there is a good chance that your two displays (the physical
panels or monitors) are either of two different sizes and/or have two
different resolutions. Somewhat more likely is the latter.

In either case, it is likely that the dpi (dots per inch) setting that
is being picked up by the X server is incorrect or biased by one display
over the other. Hence, when you open the display device on the screen,
the size and aspect ratio of the device is wrong.

For example, on my system, I have an internal 15 inch laptop lcd panel
of 1600x1200 with a dpi of 133. I have an external 20 inch lcd panel
which has the same resolution but at 100 dpi. I happen to use TwinView
with an nVidia card, but have to tweak the xorg.conf settings to get the
displays to look reasonably similar. I actually hard code the 100 dpi
setting rather than allowing the server to get the information from the
monitors. My xdpyinfo is:

$ xdpyinfo | grep dimensions
  dimensions:    3200x1200 pixels (813x305 millimeters)

$ xdpyinfo | grep resolution
  resolution:    100x100 dots per inch

Note that using TwinView, my two displays effectively show as one.

I would suggest that you post to a SUSE or generic Linux forum or
perhaps to a graphics card vendor forum specific to your card for
detailed guidance.

HTH,

Marc Schwartz


Hin-Tak Leung wrote:
> My first thought was that you must be using Xinerama or TwinView -
> and you did mention Xinerama in your r-help message but not
> in your bug report - this detail is important.
> 
> That said, I don't know enough about X11 to say anything - well, maybe
> I do, but you'll have to show your xorg.conf , and possibly the result
> of xdpyinfo for anybody to help you. I think your Xinerama setup is broken.
> 
> for the time being, you could probably run the X11 device through Xnest
> to get around this.
> 
> t.zumbrunn at unibas.ch wrote:
>> Full_Name: Thomas Zumbrunn
>> Version: 2.6.1
>> OS: GNU/Linux (openSuse 10.3 2.6.22.13-0.3-default)
>> Submission from: (NULL) (131.152.125.199)
>>
>>
>> With my particular X11 settings, the width to height ratio of the x11 device is
>> distorted, with the width being half that of the height. This results in wrongly
>> proportioned plots, wrongly positioned text etc.
>>
>> Other devices are not affected.
>>
>> I already asked about his on the mailing list
>> (https://stat.ethz.ch/pipermail/r-help/2007-December/147891.html) but no one
>> seemed to have an answer.