Re: PM3D postscript microgaps vanished from 4.0 to 4.1...

[Ethan M. <merritt@u.washington.edu>]

> > just an lucky side-effect of Ethan's changes to support pattern fills for
> > term->polygon().

Indeed it was a lucky side-effect.

> > Looking at the generated postscript, it seems as if the only significant
> > difference between 4.0.2 and 4.1 is the order of output points, and, of
> > course, the PostScript macro being used:

My conclusion from trying many combinations of PostScript maco
options on pm3d.dem is that the following change is the minimal one
sufficient to work around this ghostscript/gv bug:
> >
> > ---------4.0: ---------------
> > .3293 g 5148 927 N 0 -114 114 0 0 114 h
> > .3148 g 5033 927 N 0 -114 115 0 0 114 h
> > .2934 g 4918 927 N 0 -114 115 0 0 114 h
> >
> > /h {rlineto rlineto rlineto fill} bind def

Minimal revised version
-----------------------------

    /h {rlineto rlineto rlineto gsave fill grestore} bind def

Please check on your machines and on other test cases.
I was able to reproduce the problem with plot 7 of pm3d.dem,
but not the original problem reported on the newsgroup.

Are you OK with that as a fix for version 4.0, Petr?

As to version 4.1, I can try to trap filled quadrangles belonging to
the pm3d surface plots as a special case in the 4.1 code, 
and emit the same PostScript code that version 4.0 did.
This may send us into a period of bug-reporting when it
turns out the special-case code is either triggered or not
triggered correctly in all cases.

-- 
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center
Mailstop 357742
University of Washington, Seattle, WA 98195