title: generate png with R
body: <p>I Installed R-3.0.2 from source on Ubuntu Server 11.10 (sudo ./configure, sudo make) and want to be able to generate png-files (not view them) on the server. When i try to run "png();" in R I get the following Error:</p>
  
  <blockquote>
    <p>Error in .External2(C_X11, paste("png::", filename, sep = ""), g$width,  :
      unable to start device PNG<br />
    In addition: Warning message:<br />
    In png() : unable to open connection to X11 display ''</p>
  </blockquote>
  
  <p>Tthe following dependencies are installed:<br /></p>
  
  <blockquote>
    <p>libpng12-dev (1.2.46)<br />
    java (1.6.0_27)<br />
    xorg-dev (1:7.6+7ubuntu7.1)<br />
    libcairo-dev (1.10.2-6ubuntu3)...<br />
    <br />
    Update:<br />
    libx11-dev (2:1.4.4-2ubuntu1)<br />
    libxt-dev (1:1.1.1-2)<br /></p>
  </blockquote>
  
  <p>(could be I forgot some)</p>
  
  <p>Running capabilities(); in R give the following:</p>
  
  <blockquote>
    <p>jpeg      png     tiff    tcltk      X11     aqua http/ftp  sockets<br />
        TRUE     TRUE    FALSE    FALSE    FALSE    FALSE     TRUE     TRUE<br />
      libxml     fifo   cledit    iconv      NLS  profmem    cairo<br />
        TRUE     TRUE     TRUE     TRUE     TRUE    FALSE     TRUE</p>
  </blockquote>
  
  <p>So png is ok, but X11 seems to be missing, any idea's what I need to install/do to get png capability working in R (to get X11 up and running?) ?</p>