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

[Herbert Voss]

Uwe Siart wrote:

> 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}
> % -------------------------

I suppose it was there for ever, but I do not really know.
Could someone try the example with an old pstricks.tex
version?
However, the following may help, but there may be some
side effects ...

Herbert


\documentclass{article}
\usepackage{pstricks}
\makeatletter
\def\psgrid at iv(#1)(#2)(#3){%
   \begin at SpecialObj
     \pst at getcoor{#1}\pst at tempA
     \pst at getcoor{#2}\pst at tempB
     \pst@@getcoor{#3}%
     \ifnum\psk at subgriddiv>1
       \addto at pscode{gsave
         \psk at subgridwidth SLW \pst at usecolor\pssubgridcolor
         \pst at tempB \pst at coor \pst at tempA
         \pst at number\psxunit \pst at number\psyunit
         \psk at subgriddiv\space \psk at subgriddots\space
         {} 0 \tx at Grid grestore
       }%
     \fi
     \addto at pscode{%
       gsave
       \psk at gridwidth SLW \pst at usecolor\psgridcolor
       \pst at tempB \pst at coor \pst at tempA
       \pst at number\psxunit abs \pst at number\psyunit abs
%      \pst at number\psxunit \pst at number\psyunit
       1 \psk at griddots\space { \pst at usecolor\psgridlabelcolor }
       \psk at gridlabels \tx at Grid grestore
     }%
   \end at SpecialObj%
}
\makeatother
\psset{unit=-1cm,
griddots=5, subgriddiv=0}
\begin{document}
\begin{pspicture}(0,0)(3,3)
\psgrid
\end{pspicture}
\end{document}



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