🚀 go-pugleaf

If you don't execute flattenpath before pathbox, you will get a bounding
box for the knots and control points of the path, not of the pat itself.
The bounding box may be larger than that of the character outline as a
result of the fact that the control points do not lie on the path.
Conversely, the bounding box of the knots and control points may be smaller
then that of the character because a part of the outline may `bulge out'
betwen control points.

In a properly designed Type 1 font this is not a problem since there must be
knots at all extrema of the outline and so all control points lie in or on the
character outline bounding box.  But in some Type 1 fonts this is not the
case, and it certainly isn't the case in the typical Type 3 font (if there
is such a thing)...

Berthold.