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

[Hans-Bernhard B. <br...@ph...>]

On Thu, 15 Jul 2004, Ethan Merritt wrote:

> 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:

> > /h {rlineto rlineto rlineto fill} bind def
> 
> Minimal revised version
> -----------------------------
> 
>     /h {rlineto rlineto rlineto gsave fill grestore} bind def

Hmmm.... let me try my understanding of PostScript on this.  What this
change does is to cause a copy of the patch constructed by the 'N' (-->
newpath moveto) and the three rlinetos alive to still be sitting on the
stack after the 'fill'.  And the 'g' operator of the *next* quadrangle
will then stroke this path.  

Yes, that figures.  IIRC, the PostScript drawing model explicitly says
that the fill operator *only* fills the interior of the path, leaving its
outline alone.  This will indeed cause hairline fractures between adjacent
rectangles: each fill will leave the shared edge itself alone, so it stays
white.  The change pastes over the cracks using the stroke operator.

-- 
Hans-Bernhard Broeker (br...@ph...)
Even if all the snow were burnt, ashes would remain.