3
\documentclass[pstricks,border=12pt]{standalone}
\begin{document}
\begin{pspicture}[showgrid](-1,-1)(4,4)
\psellipticarc[showpoints]{->}(.5,0)(1.5,1){215}{0}
\psarc*[showpoints](1.5,1.5){1.5}{215}{0}
\end{pspicture}
\end{document}

enter image description here enter image description here enter image description here

Update:

\documentclass[pstricks,border=12pt]{standalone}
\begin{document}
\begin{pspicture}[showgrid](-1,-1)(4,4)
\psarc*[showpoints](1.5,1.5){1.5}{215}{0}
\psellipticarc[showpoints]{->}(.5,0)(1.5,1){215}{0}
\end{pspicture}
\end{document}

It produces true result

enter image description here Question:

How to fix it?

How to the star version be more beautiful?

1
\documentclass[pstricks,border=12pt]{standalone}
\begin{document}
\begin{pspicture}[showgrid](-1,-1)(4,4)
%
\psellipticarc[linecolor=red,correctAngle=false]{->}(1,2)(1,2){215}{0}
\rput(1,2){%
    \psset{linestyle=dashed}%
    \psline(!1 2 215 PtoCab)(0,0)%
    \psline(0,0)(!1 2 0 PtoCab)}
%
\psarc*(3,3){1}{215}{0}
\rput(3,3){%
    \psset{linestyle=dashed}%
    \psline(!1 215 PtoC)(0,0)%
    \psline(0,0)(!1 0 PtoC)}
\end{pspicture}
\end{document}

enter image description here

About correctAngle

An ellipse can be parameterized as x=a cos t and y= b sin t where t is a parameter that does not represent an angle relative to the x axis.

If you write, for example \psellipticalarc(0,0)(1,2){0}{45} with the default correctAngle=true then it draws an elliptical arc that starts from 0 degrees to 45 degrees.

However, if you write, for example \psellipticalarc[correctAngle=false](0,0)(1,2){0}{45} then it draw an elliptical arc that starts from 0 degrees to arctan(2) degrees. Here 45 does not represent an angle relative to the x axis.

Thus, correctAngle=true can be read as "make the parameter as a real angle".

2

With pstricks.tex from http://archiv.dante.de/~herbert/texnik/tex/generic/pstricks/

\documentclass[pstricks,border=12pt]{standalone}
\begin{document}
\begin{pspicture}[showgrid](-1,-1)(5,4)
    \psarc[showpoints](0.25,0.5){1.5}{215}{0}
    \psarc*(3.25,2){1.5}{215}{0}
    \psarc(3.25,0.5){1.5}{215}{0}
    \psarc*[showpoints](0.25,2){1.5}{215}{0}
    \psellipticarc[showpoints,linecolor=red](0,3)(1.5,1){215}{0}
    \psellipticarc*[showpoints,linecolor=red](0,4)(1.5,1){215}{0}
    \psellipticarc[linecolor=red](3,3)(1.5,1){215}{0}
    \psellipticarc*[linecolor=red](3,4)(1.5,1){215}{0}
\end{pspicture}
\end{document}

enter image description here

For correctAngle read http://mirrors.ctan.org/graphics/pstricks/base/doc/pst-news10.pdf section 3.4, page 8

  • With \psarc*[showpoints](0.25,2){1.5}{215}{0} and \psellipticarc*[showpoints,linecolor=red](0,4)(1.5,1){215}{0} , it poduces dash line belong black area. Ugly. How to ignore it? – Trong Vuong Dec 29 '18 at 14:12
  • It is obviously, that showpoints will draw the help lines. Do not use it if you do not want it! – user2478 Dec 29 '18 at 14:54
  • @Herbert \psarc*(1.5,1.5){1.5}{215}{0} \psarc[showpoints](1.5,1.5){1.5}{215}{0} are more beautiful \psarc*[showpoints](1.5,1.5){1.5}{215}{0}. Are you ok? – Trong Vuong Dec 29 '18 at 15:04
  • I already wrote: That are help lines to see where the origin is. If you want other lines then use \psline! – user2478 Dec 29 '18 at 16:16
  • Yes, I see ah. :-) – Trong Vuong Dec 29 '18 at 16:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.