type: double, default:
Specifies the width of the pen, in points, used to draw lines and curves, including the boundaries of edges and clusters.
penwidth value is inherited by subclusters, and has no effect on text.
Previous to 31 January 2008, the effect of
penwidth=W was achieved by
setlinewidth(W) as part of a
If both attributes are set,
penwidth will be used.