Mark's "PostScript error"

[Jeff Kingston]

I haven't seen this "invalidfont Command: stringwidth" or anything like
it on the printers here.  The stringwidth command is pretty standard
so the problem is probably better described as a bug than as a less than
full implementation of PostScript.  The stringwidth command is used by
Graph to work out the width of the label under that first X tick, so
that it can be centred.  No way to avoid that, I'm afraid.

Jeff.