# [pstricks] Ending a psline on pscircle

Luis Sequeira lfsequeira at gmail.com
Wed Feb 12 21:03:23 CET 2014

>> I suppose you are looking for something like that
>
> Herbert,
>
>   I'll need to play with your code to understand how to use it well.
>
>   Yesterday's figure is what prompted me to write (code modified from what
> worked in previous figures; probably not optimum):
>
> \documentclass[12pt,letterpaper]{article}
> \usepackage[margin=1cm]{geometry}
> \newsavebox\PSTBox
>
> \begin{document}
>
>   \psset{framesep=2mm,arrowscale=1.75}
>
>   %\begin{pspicture}[showgrid](-1.0,-0.25)(15,15)
>   \begin{pspicture}(-1.0,-0.25)(15,15)
>     \pscircle(5,5){4.7cm}
>     \pscircle(10.5,5){4.0cm}
>     \psline[linewidth=3pt](5,5)(10.5,5)
>     \psline[linewidth=3pt](5,5.25)(5,4.75)
>     \psline[linewidth=3pt](10.5,5.25)(10.5,4.75)
>     \psline{->}(5,5)(2.18,1.18)
>     \psline{->}(10.5,5)(12.68,1.6)
>     \psline{->}(8.3,8.3)(8.3,5)
>     \rput(5,5.6){2006}
>     \rput(10.5,5.6){2005}
>     \rput(8.3,4.5){2004}
>     \rput(2.6,3.7){Circle with}
>     \rput(12.75,3.7){Circle with}
>   \end{pspicture}
> \end{document}

Like Werner wrote, you need to enter the \SpecialCoor command somewhere in the pspicture environment, and then your radii can be just writen very easily with polar coordinates:

\SpecialCoor
\psline[origin={5,5}]{->}(4.7;240) %polar coordinates: radius & angle, separated by ‘;’
\psline[origin={10.5,5}]{->}(4;320)

(Note the setting of origin at the center of each circle; this makes the coordinates of the line end relative to the center; that is what makes polar coordinates so simple)

The last one (the vertical line) is trickier, and you need a little calculation, though it is basic algebra.
Your value of 8.3 is not far (8.303636363…) and from there you can find the y coordinate with the Pythagorean theorem, giving 8.34305...

Luis Sequeira