# PSTricks question (clipping and \textpath)

Denis Girou Denis.Girou at idris.fr
Wed Jun 18 23:11:45 CEST 1997

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The following message is a courtesy copy of an article
that has been posted to comp.text.tex as well.

>>>>> "Jonas.Bofjall" == Jonas Bofjall <m9418 at abc.se> writes:

Jonas.Bofjall> Is it at all possible to clip an \psbezier line using another \psbezier as
Jonas.Bofjall> the clipping path? I tried something like:

Jonas.Bofjall> \psclip{\psbezier{-}(0,1)(.3,1)(.7,.5)(1,.5)}{
Jonas.Bofjall>   \psbezier{-}(1,1)(.7,1)(.3,.5)(0,.5)}
Jonas.Bofjall> \endpsclip

Jonas.Bofjall> but the result is that only the first line (the clipping path)
Jonas.Bofjall> is displayed? Am I doing something wrong?

Problem is related to positions of begin and end points for clipping.
Clipping occur for the region delimited by the curve and the line connecting
begin and end points. You can verify that there is nothing to clip in your
region... And it's a general problem not related to \psbezier, as you can
verify that it's occur too with \psline, for instance.

A workaround is to add an invisible point to the clipping region.

\documentclass{article}

\usepackage{pstricks}

\begin{document}

\psset{unit=4}

\psbezier[showpoints=true](0,1)(.3,1)(.7,.5)(1,.5)
\psline[linecolor=red](0,1)(1,.5)
\psbezier[showpoints=true](1,1)(.7,1)(.3,.5)(0,.5)

\vspace{4cm}
\psbezier[showpoints=true](0,1)(.3,1)(.7,.5)(1,.5)
\psline[linecolor=green](1,.5)(1,1)
\psline[linecolor=red](0,1)(1,1)
\psbezier[showpoints=true](1,1)(.7,1)(.3,.5)(0,.5)

\vspace{4cm}
\psclip{\pscustom[linestyle=none]{%
\psbezier(0,1)(.3,1)(.7,.5)(1,.5)
\lineto(1,1)}}
\psbezier(1,1)(.7,1)(.3,.5)(0,.5)
\endpsclip

\vspace{4cm}
\psbezier(1,1)(.7,1)(.3,.5)(0,.5) % To see it
\psclip{\pscustom[linestyle=none]{%
\psbezier(1,1)(.7,1)(.3,.5)(0,.5)
\lineto(0,1)}}
\psbezier(0,1)(.3,1)(.7,.5)(1,.5)
\endpsclip

\end{document}

Jonas.Bofjall> By the way, is there something like \textpath which works on graphics
Jonas.Bofjall> objects? One that could make a zig-zaged sinewave?

\textpath work only for few graphic objects, but is not restricted to
\pscurve only. As it's work too with \psplot, you have a lot of possibilities.
Here is an example with a sinus:

\documentclass{article}

\usepackage{pstricks}
\usepackage{pst-text}
\usepackage{pst-plot}

\begin{document}

\pstextpath{\psplot[plotpoints=300,xunit=0.015,yunit=3]{0}{540}{x sin}}
{\LARGE This text follow exactly the sinusoidal curve...}

\end{document}

Denis Girou
--

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