Garfield uses HIGZ/CERNLIB to render graphics.
The ps file header is:
%!PS-Adobe-2.0
%%Title: garfield.ps (Portrait A 4)
%%Pages: (atend)
%%Creator: HIGZ Version 1.29/04
%%CreationDate: 2014/06/24 10.52
%%EndComments
%%BeginProlog
As far as I can see the plots look reasonable seems to me. I do not see anything out of scale.