WCEN FAQ (for Linux)

Question 0. "wcen: command not found"

Solution. Update the PATH environmental variable so that the system knows where wcen is.

For bash users: open ".bashrc" in your home directory, add a line 
          PATH=wcenpath:$PATH
          where wcenpath is the actual path of wcen, e.g., ${HOME}/bin/wcen, ~/bin/wcen.

For csh or tcsh users: open ".cshrc" or ".tcshrc", add a line
          setenv PATH "wcenpath:${PATH}"

Save the change and execute the command "source .bashrc" or "source .cshrc" or "source .tcshrc" to get the change into effect. If you are not sure which shell you are using, type "echo $SHELL" on the command line.


Question 1. "user not authorized to run the X server"

Solution. Login as root, run the command "dpkg-reconfigure xserver-common" and select "allow everybody to open X", or make the X server setuid and setgid (chmod 6755 /usr/bin/X).


Question 2. "Error while loading shared libraries: libXy.so.z: cannot open shared object file: No such file or directory"

Solution 1. download the static linked version of WCEN

Solution 2. go to /usr/X11R6/lib/, type command "ls -l libXy.*", see what versions of "libXy" are there. Usually you can make a copy of the file and rename it to "libXy.so.z" (z is the version number). Note that you need copy the actual file, not the links (they have a "l" leading the "rw..." in the first column of the "ls -l" output).


Question 3. "How do I set up PseudoColor visual on my system?"

Solution 1. Open a second display of 8-bit depth. You can do this in a number of ways:

<1> Try the script "x8" included in WCEN package, or use command "startx -- :1 -depth 8 &" or "startx -- :1 -bpp 8 &" or "startx -- :1 -cc 3 &i;". If none works, try "startx -- :1 -depth 8 -bpp 8 -cc 3 &". Please notes that if you already have two X servers running, then the ":1" should be ":2", and so forth, since the first X server is :0. Once a new display is opened, you can open a terminal or window to run WCEN (the root menu in the new display can usually be accessed by left or right click on the screen). You can switch between the two displays with Ctrl + Alt + Fn keys (to find out which n to use, look at the output of "ps -ef |grep X |grep vt". For example, if you see ".../usr/X11R6/bin/X :0 -auth /var/gdm/:0.Xauth vt7", then pressing Ctrl + Alt + F7 would take you to the original display, and Ctrl + Alt + F8 would take you to the second display); or

<2> Use the command "Xnest -depth 8 :1 &" or "Xnest -class PseudoColor :1", where 1 is the display number, if you already have two, use 2 (the first one is 0), such and such. The command will open a nested X server (other applications in :0 are still visible and in TrueColor), then you can run wcen, by type "wcen -display :1" in the same terminal. The Xnest grammar might vary on different systems, and you can check it by "man Xnest".

Solution 2. Run a VNC session. If your system doesn't have VNC installed (There should be a VNC server and a VNC viewer, try "where vncserver" and "where vncviewer" see if they are there), download them here: http://www.tightvnc.com/download.html.

What VNC does is opening a virtual X server and allows clients to access it with VNC viewer (sort of a desktop). To run WCEN, you first start a VNC server with depth of 8, "vncserver :1 -depth 8 -cc 3 &", then start a VNC viewer connecting to the server, "vncviewer :1". You can then run WCEN in the xterm, or make wcen automatically start by adding a line of "wcenpath/wcen &" in the vnc configuration file ("yourhomedir/.vnc/xstartup");

Solution 3. Setup your system to run in "overlay" mode or PseudoColor mode:

First check what visuals are available on your system by the command "xdpyinfo", see if you have something similar to the following in your output:

------------------------------
    visual id:    0x22
    class:    PseudoColor
    depth:    8 planes
    available colormap entries:    256
    red, green, blue masks:    0x0, 0x0, 0x0
    significant bits in color specification:    8 bits
------------------------------

If not, you'll need modify your X configuration file. In your /etc/X11/, there should be a file named "XF86Config", or "xorg.conf", or you can find the file by the command "grep Section * | grep Screen". For simplicity we'll hereby call it "Xconf". Log in as root (with "su" command) , make a backup copy of "Xconf", then open "Xconf", find the Section "Screen", make it similar to the following example. Save the change, logout and log back in, your display should now have a Visual class of PseudoColor. You can use "xdpyinfo" to check it. What we are doing is enabling the "overlay" of the graphics card so that it can emulate an 8-bit PseudoColor visual in 24-bit TrueColor/DirectColor environments.

------------------------------------------------
Section "Screen"
       Identifier "Screen0"
       Device     "Videocard0"
       Monitor    "Monitor0"
       DefaultDepth     24
       Option     "Dac8Bit" "TRUE"
       Option     "OverlayDefaultVisual" "TRUE"
       Option           "CIOverlay" "TRUE"
       Option           "Overlay" "TRUE"

       SubSection "Display"
               Depth     8
               Modes    "1152x864" "1024x768" "800x600" "640x480"
       EndSubSection

       SubSection "Display"
               Depth     24
               Modes     "1152x864" "1024x768" "800x600" "640x480"
       EndSubSection
EndSection
------------------------------------------------

If you have PseudoColor in "xdpyinfo" output, but still unable to run WCEN, you can try change the "DefaultDepth" to 8, and it should make PseudoColor the default visual which can be seen in "xdpyinfo" output:

------------------------------------------------
  default visual id:  0x22
  visual:
    visual id:    0x22
    class:    PseudoColor
    depth:    8 planes
    available colormap entries:    256
    red, green, blue masks:    0x0, 0x0, 0x0
    significant bits in color specification:    8 bits
------------------------------------------------

The above "overlay" code is for nVidia Quadro cards (more information). If it doesn't work for you, please look up your graphics card manual and see how to make it support PseudoColor. You can usually get the information from manufacturer's website, or, try google it, e.g. "nVidia + PseudoColor + overlay". You can get the name of your graphics card from "Xconf", under the Section "Device", or you can get it from your system information console, or just open the computer box and see it.

In some cases your system might not have Linux driver installed for your graphics card. In this case, you need install it first or the overlay option won't work. Here is a summary of Graphics Cards for Linux.