Graphics, Figures & Tables ⇒ pst-poly | Center and Radius of Polygon

[svend_tveskaeg]

Hi all.

Consider the following MWE:

Code: Select all

\documentclass{article}

\usepackage{auto-pst-pdf,pst-poly}

\begin{document}

\begin{figure}
\def\radius{3 }
 \centering
  \begin{pspicture}(6,6)
   \pscircle(!\radius \radius){\radius}
   \PstPentagon[PolyNbSides=6]
  \end{pspicture}
\end{figure}

\end{document}

How do I specify the center and the radius of the hexagon? (I have had a look at the pst-poly documentation but that did not help me.)

Thank you in advance!

P.S. I am trying to draw the figure that is produced by compiling the following (not very elegant) code:

Code: Select all

\documentclass{article}

\usepackage{auto-pst-pdf,pstricks-add}
\usepackage[locale=DE]{siunitx}
\usepackage{expl3}

\ExplSyntaxOn
  \cs_new_eq:NN
    \calculate
  \fp_eval:n
\ExplSyntaxOff

\begin{document}

\begin{figure}
\def\radius{3.5 }
\def\maksimum{\calculate{2*\radius} }
 \centering
  \begin{pspicture}(\maksimum,\maksimum)
   \pnode(!\radius \radius){X}
   \pscircle(X){\radius}
   \pnode(!2 \radius mul \radius){A}
   \pnode(!3 2 div \radius mul 2 3 sqrt add 2 div \radius mul){B}
   \pnode(!1 2 div \radius mul 2 3 sqrt add 2 div \radius mul){C}
   \pnode(!0 \radius){D}
   \pnode(!1 2 div \radius mul 2 3 sqrt sub 2 div \radius mul){E}
   \pnode(!3 2 div \radius mul 2 3 sqrt sub 2 div \radius mul){F}
   \pspolygon(A)(B)(C)(D)(E)(F)
  \psset{linestyle=dotted,nrot=:U}
   \pcline(A)(D)
   \pcline(B)(E)
   \pcline(C)(F)
   \pcline[offset=7pt,linecolor=white](X)(B)
   \ncput*{\footnotesize{$r = \SI{\radius}{\cm}$}}
  \end{pspicture}
\end{figure}

\end{document}

[localghost]

[…] (I have had a look at the pst-poly documentation but that did not help me.) […]

Hard to believe since the manual is full of examples.

If you want to draw a hexagon, you should not use \PstPentagon but \PstHexagon instead. Furthermore you can specify the unit scale for every single command.

Code: Select all

\documentclass{standalone}
\usepackage{pst-poly,pstricks-add}
\usepackage{auto-pst-pdf}

\begin{document}
  \def\radius{3 }
  \begin{pspicture}[showgrid=false](6,6)
    \pscircle(!\radius \radius){\radius}
    \PstHexagon[unit=\radius]
  \end{pspicture}
\end{document}

The hexagon (or a polygon in general, respectively) is by default not drawn regularly around the coordinate origin. You have to add the PstPicture=false option (or do this globally by \psset).


Thorsten

[svend_tveskaeg]

[…] (I have had a look at the pst-poly documentation but that did not help me.) […]

Hard to believe since the manual is full of examples.

Hmm... Would you please direct me to the page where the center of the \PstHexagon is specified? (I do not always want the circle to be indside a box going from (0,0) to (2r,2r) where r is the radius.)

If you want to draw a hexagon, you should not use \PstPentagon but \PstHexagon instead. Furthermore you can specify the unit scale for every single command.

Great. Thank you!

[localghost]

[…] Would you please direct me to the page where the center of the \PstHexagon is specified? […]

Take a look at the example of the perspective model on page 7 of the pst-poly manual. You can place every kind of polygon arbitrarily by the \rput command.

[svend_tveskaeg]

Thank you, Thorsten!

I tried to make to drawing as `automatic' as possible, so I had a look at the first example at page 30 in the pstricks-add manual. Here is what I came up with

Code: Select all

\documentclass{article}

\usepackage{auto-pst-pdf,pst-poly,pstricks-add}
\usepackage[locale=DE]{siunitx}
\usepackage{expl3}

\ExplSyntaxOn
  \cs_new_eq:NN
    \calculate
  \fp_eval:n
\ExplSyntaxOff

\begin{document}

\begin{figure}
\def\NumSides{8 }
\def\Radius{3.5 }
\def\Maximum{\calculate{2*\Radius} }
\def\RelAngle{\calculate{360/\NumSides} }
 \centering
  \begin{pspicture}[showgrid=false](\Maximum,\Maximum)
   \pnode(!\Radius \Radius){A}
   \pnode(!2 \Radius mul \Radius){B}
   \pcline[offset=6pt,linecolor=white](A)(B)
   \ncput*{\footnotesize{$r = \SI{\Radius}{\cm}$}}
   \pscircle(A){\Radius}
   \PstPolygon[PolyNbSides=\NumSides,unit=\Radius]
   \multido{\r=0+\RelAngle}{\NumSides}{\psRelLine[angle=\r,linestyle=dotted](A)(B){1}{C}}
  \end{pspicture}
\end{figure}

\end{document}

This is almost as I want it, but when

gcd(\NumSides, 360) = 1

there is a problem. The dotted lines do not exactly intersect with the vertices of the regular polygon and a numerical value of

"some integer"/\NumSides

is printed next to the figure. (I think that \RelAngle is rounded to an integer, which is a problem, but I am fare from sure that this is the problem.)

How do I solve this?

Thank you in advance!

Update:
I found the problem. In \multido it must (of course) be \rA instead of \iA., i.e., the complete code is

Code: Select all

\documentclass{article}

\usepackage{auto-pst-pdf,pst-poly,pstricks-add}
\usepackage[locale=DE]{siunitx}
\usepackage{expl3}

\ExplSyntaxOn
  \cs_new_eq:NN
    \calculate
  \fp_eval:n
\ExplSyntaxOff

\begin{document}

\begin{figure}
\def\NumSides{6 }
\def\Radius{3.5 }
\def\Maximum{\calculate{2*\Radius} }
\def\RelAngle{\calculate{360/\NumSides} }
 \centering
  \begin{pspicture}[showgrid=false](\Maximum,\Maximum)
   \pnode(!\Radius \Radius){A}
   \pnode(!2 \Radius mul \Radius){B}
   \pcline[offset=6pt,linecolor=white](A)(B)
   \ncput*{\small{$r = \SI{\Radius}{\centi\metre}$}}
   \pscircle(A){\Radius}
   \PstPolygon[PolyNbSides=\NumSides,unit=\Radius]
   \multido{\r=0+\RelAngle}{\NumSides}{%
     \psRelLine[angle=\r,linestyle=dotted](A)(B){1}{C}
   }
  \end{pspicture}
\end{figure}

\end{document}