title: How do I enable the pngcairo terminal in Gnuplot
body: <p>I would like to plot a figure to PNG format (avoiding using convert), however my Gnuplot distribution does not offer the PNGCAIRO terminal. How can I install/enable it? I use Gnuplot 4.4, patchlevel 2 on Mac OS X 10.6.</p>
  
  <pre><code>[me]machine @ test $ gnuplot
  
  G N U P L O T
  Version 4.4 patchlevel 2
  last modified Wed Sep 22 12:10:34 PDT 2010
  System: Darwin 10.8.0
  
  Copyright (C) 1986-1993, 1998, 2004, 2007-2010
  Thomas Williams, Colin Kelley and many others
  
  gnuplot home:     http://www.gnuplot.info
  faq, bugs, etc:   type "help seeking-assistance"
  immediate help:   type "help"
  plot window:      hit 'h'
  
  Terminal type set to 'x11'
  gnuplot&gt; set terminal pngcairo
                        ^
       unknown or ambiguous terminal type; type just 'set terminal' for a list
  </code></pre>