r/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if <em class="parameter"><code>level</code></em>
 id isn't valid. See <a class="link" href="cairo-PostScript-Surfaces.html#cairo-ps-get-levels" title="cairo_ps_get_levels ()"><code class="function">cairo_ps_get_levels()</code></a>
for a way to get the list of valid level ids.</p>
<div class="refsect3">
<a name="cairo-ps-level-to-string.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table cl