[pstricks] Errors with 'griddots' and negative 'unit'

[Uwe Siart]

Hello all,

I'm getting errors in GSview when using 'griddots' together with
negative unitlengths.

This example

% -------------------------
\documentclass{article}
\usepackage{pstricks}
\psset{unit=-1cm,
       griddots=5}
\begin{document}
\begin{pspicture}(0,0)(3,3)
  \psgrid
\end{pspicture}
\end{document}
% -------------------------

produses these messages in GSview (linewrapped):

% --------------------------------------------------------------------
AFPL Ghostscript 8.51 (2005-04-18) Copyright (C) 2005 artofcode LLC,
Benicia, CA. All rights reserved. This software comes with NO WARRANTY:
see the file PUBLIC for details. Displaying DSC file
E:/user/siart/temp/t.ps Displaying page 1 Loading NimbusSanL-Regu font
from C:\Programme\gs\fonts/n019003l.pfb... 2311416 954907 1939016 601869
4 done. Error: /rangecheck in --setdash-- Operand stack: --nostringval--
-2.84527 Execution stack: %interp_exit .runexec2 --nostringval--
--nostringval-- --nostringval-- 2 %stopped_push --nostringval--
--nostringval-- false 1 %stopped_push 1 3 %oparray_pop 1 3 %oparray_pop
1 3 %oparray_pop 1 3 %oparray_pop .runexec2 --nostringval--
--nostringval-- --nostringval-- 2 %stopped_push --nostringval--
--nostringval-- 2 6 %oparray_pop Dictionary stack:
--dict:1130/1686(ro)(G)-- --dict:0/20(G)-- --dict:76/200(L)--
--dict:175/300(L)-- --dict:37/200(L)-- --dict:101/200(L)-- Current
allocation mode is local

--- Begin offending input --- %%Page: 1 1 TeXDict begin 1 0 bop 0
TeXcolorgray Black 0 TeXcolorgray 639 440 a @beginspecial @setspecial
tx at Dict begin STP newpath 0.8 SLW 0 setgray gsave 0.4 SLW 0.5 setgray
0.0 0.0 85.35823 -85.35823 0.0 0.0 28.45274 -28.45274 5 0 {} 0 Grid
grestore gsave 0.8 SLW 0 setgray 0.0 0.0 85.35823 -85.35823 0.0 0.0
28.45274 -28.45274 1 5 { 0 setgray } 10.0 Grid grestore end
 
@endspecial 0 TeXcolorgray 1926 5255 a Fa(1)p 0 TeXcolorgray eop end

--- End offending input ---
file offset = 0
gsapi_run_string_continue returns -101
% --------------------------------------------------------------------

 *File List*
 article.cls    2004/02/16 v1.4f Standard LaTeX document class
  size10.clo    2004/02/16 v1.4f Standard LaTeX file (size option)
pstricks.sty    2004/05/12 v0.2l LaTeX wrapper for `PSTricks' (RN,HV)
pstricks.tex    2005/05/06 v1.07 `PSTricks' (tvz)
  xcolor.sty    2005/06/06 v2.03 LaTeX color extensions (UK)
   color.cfg    2003/03/08 v1.0 MiKTeX 'color' configuration
   dvips.def    1999/02/16 v3.0i Driver-dependant file (DPC,SPQR)
 ***********

I'm not sure if this was also the case in earlier versions of
pstricks.tex so I report it to the list.

Thanks.

-- 
Uwe