# Rotate PSTricks Object: Label Positioning

Consider the following (non-minimal) example of a rotation of a quadrilateral around a point:

\documentclass{article}

\usepackage{xfp}

\begin{document}

\def\Ax{-1}
\def\Ay{4}
\def\Bx{-2}
\def\By{3}
\def\Cx{-1}
\def\Cy{1}
\def\Dx{0}
\def\Dy{3}
\def\Ex{1}
\def\Ey{2}
\def\rotation{90}
\def\punkt(#1){%
\def\str{0.1}
\rput(#1){%
\psline(-\str,-\str)(\str,\str)
\psline(-\str,\str)(\str,-\str)}
\uput[45](#1){$#1$}}%
\begin{pspicture}(-2.45,-1.12)(2.05,4.4)
\pnodes(\Ax,\Ay){A}(\Bx,\By){B}(\Cx,\Cy){C}(\Dx,\Dy){D}(\Ex,\Ey){E}
{\psset{
linewidth = 1.5\pslinewidth,
fillstyle = solid,
fillcolor = cyan!50
}
\pspolygon(A)(B)(C)(D)
\psrotate(E){\rotation}{%
\pspolygon[
linecolor = red
](\Ax,\Ay)(\Bx,\By)(\Cx,\Cy)(\Dx,\Dy)
\uput[180]{\fpeval{360-\rotation}}(\Ax,\Ay){$A'$}
\uput[270]{\fpeval{360-\rotation}}(\Bx,\By){$B'$}
\uput[90]{\fpeval{360-\rotation}}(\Cx,\Cy){$C'$}
\uput[90]{\fpeval{360-\rotation}}(\Dx,\Dy){$D'$}}}
\uput[90](A){$A$}
\uput[180](B){$B$}
\uput[270](C){$C$}
\uput[0](D){$D$}
\punkt(E)
\end{pspicture}

\end{document}

The nodes A'--D' are not placed as I expected; I would like A' to be placed to the left of the vertex A, B' below the vertex B, and so on.

How do I achieve this?

The trick (!!) is to not forget the polar axis, used for the direction along which the label is put, was also rotated. Whence:

\documentclass{article}

\usepackage{auto-pst-pdf}

\begin{document}

\def\Ax{-1}
\def\Ay{4}
\def\Bx{-2}
\def\By{3}
\def\Cx{-1}
\def\Cy{1}
\def\Dx{0}
\def\Dy{3}
\def\Ex{1}
\def\Ey{2}
\def\rotation{90}
\def\punkt(#1){%
\def\str{0.1}
\rput(#1){%
\psline(-\str,-\str)(\str,\str)
\psline(-\str,\str)(\str,-\str)}
\uput[45](#1){$#1$}}%
\begin{pspicture}(-2.45,-1.12)(2.05,4.4)
\pnodes(\Ax,\Ay){A}(\Bx,\By){B}(\Cx,\Cy){C}(\Dx,\Dy){D}(\Ex,\Ey){E}
{\psset{
linewidth = 1.5\pslinewidth,
fillstyle = solid,
fillcolor = cyan!50
}
\pspolygon(A)(B)(C)(D)
\psrotate(E){\rotation}{%
\pspolygon[
linecolor = red
](\Ax,\Ay)(\Bx,\By)(\Cx,\Cy)(\Dx,\Dy)
\uput[90]{-\rotation}(\Ax,\Ay){$A'$}
\uput[180]{-\rotation}(\Bx,\By){$B'$}
\uput[-90]{-\rotation}(\Cx,\Cy){$C'$}
\uput[0]{-\rotation}(\Dx,\Dy){$D'$}}}
\uput[90](A){$A$}
\uput[180](B){$B$}
\uput[270](C){$C$}
\uput[0](D){$D$}
\punkt(E)
\end{pspicture}

\end{document}

• You're welcome. It's a pleasure to help. – Bernard Jun 6 '16 at 19:34
• @SvendTveskæg: I don't even remember what the removed code was supposed to do. If it works without it, I agree, of course. Thanks for having simplified! – Bernard Apr 22 '17 at 13:47
\uput[180]{E}(\Ax,\Ay){$A'$}
\uput[270]{E}(\Bx,\By){$B'$}
\uput[0]{E}(\Cx,\Cy){$C'$}
\uput[90]{E}(\Dx,\Dy){$D'$}}}
• This only works for a rotation of 90 degrees, I think. – Svend Tveskæg Jun 15 '16 at 23:32