Graphics, Figures & Tables ⇒ PSTricks syntax

[svend_tveskaeg]

Hi all.

Consider the following code, with which Herbert Voß helped me over at {TeX} SX:

Code: Select all

\documentclass{article}

\usepackage{pst-solides3d}
\usepackage{expl3}

%% Parameters
% Windings
\def\lWind{20}
\def\rWind{10}
% Radii
\def\rHelix{1.11}
\def\rWire{0.015}

% Floating point calculations
\ExplSyntaxOn
  \cs_new_eq:NN
    \calc
  \fp_eval:n
\ExplSyntaxOff
% Constants
\def\factor{80} % \factor > \lWind,\rWind
\def\nLeft{\calc{2*\lWind/\factor} }
\def\nRight{\calc{2*\rWind/\factor} }

%% Colours
\colorlet{wireColor}{red!60}
\colorlet{coreColor}{cyan!50}
%% Wire
\newpsobject{wire}{psSolid}{%
  object=courbe,
   % Choose max(\nRight,\nLeft) -- the fewer windings, the larger
   % the constant multiplied by max(\nRight,\nLeft)
  ngrid=970 \nLeft mul cvi 15,
  r=\rWire,
  fillcolor=wireColor,
  incolor=wireColor
}

\pagestyle{empty}

\begin{document}

\begin{figure}[htbp]
 \centering
  \begin{pspicture}(-5,-5)(5,5)
   \psset{%
     algebraic,
     viewpoint=20 5 10 rtp2xyz,
     lightsrc=20 60 60 rtp2xyz,
     Decran=30,
     solidmemory,
     action=none,
     grid=false
   }
   %%--------- Core ----------
   \psSolid[object=anneau,h=1.0,R=4,r=2.5,ngrid=4,RotZ=90,RotY=45,RotX=90,
     fillcolor=coreColor,name=core]
   %%--------- Wire ----------
   % Left
   \defFunction{heliceA}(t){\rHelix*cos(\factor*t)}{\rHelix*sin(\factor*t)}%
     {t/\nLeft}
   \wire[function=heliceA,range=0 Pi \nLeft mul,name=wireA](0,-2.25,-1.5)
   % Right
   \defFunction{heliceB}(t){\rHelix*cos(\factor*t)}{-\rHelix*sin(\factor*t)}%
     {t/\nRight}
   \wire[function=heliceB,range=0 Pi \nRight mul,name=wireB](0,2.25,-1.5)
   %%------- Assembly --------
   \psSolid[object=fusion,base=core wireA wireB,action=draw**]
  \end{pspicture}
\end{figure}

\end{document}

I have a rather embarrassing problem; how do I write the calculations for \nLeft and \nRight if I want PSTricks to do them without activating the L3 fp syntax? I have tried

Code: Select all

\def\nLeft{2 \lWind mul \factWind div }
\def\nRight{2 \rWind mul \factWind div }

but that leads to an error.

Thank you in advance!

[Stefan Kottwitz]

Those values are constants, you could calculate them in another way, such as with the fp package. Also pgf provides floating point calculation, you could even use just the calculation but do the graphic with PSTricks. But I remember you don't use pgf/TikZ.

Stefan

[svend_tveskaeg]

I know of the fp package but can it not be done without loading this? I have a feeling that it should be easy and that I am just "blind" at the moment.

I cannot even see why my try shouldn't work.

[CrazyHorse]

Code: Select all

\def\nLeft{2 \lWind mul \factWind div }
\def\nRight{2 \rWind mul \factWind div }

but that leads to an error.

define

Code: Select all

\pstVerb{
  /nLeft 2 \lWind mul \factWind div def
  /nRight 2 \rWind mul \factWind div def
}

then you can use nLeft and nRight as PostScript variables in your other macros.

[svend_tveskaeg]

@Herbert:
I am not exactly sure how to do this. If I try

Code: Select all

\documentclass{article}

\usepackage{pst-solides3d}

%% Parameters
% Windings
\def\lWind{20}
\def\rWind{10}
% Radii
\def\rHelix{1.11}
\def\rWire{0.015}

% Constants
\def\factor{80} % \factor > \lWind,\rWind
\pstVerb{
  /nLeft 2 \lWind mul \factor div def
  /nRight 2 \rWind mul \factor div def
}

%% Colours
\colorlet{wireColor}{red!60}
\colorlet{coreColor}{cyan!50}
%% Wire
\newpsobject{wire}{psSolid}{%
  object=courbe,
   % Choose max(\nRight,\nLeft) -- the fewer windings, the larger
   % the constant multiplied by max(\nRight,\nLeft)
  ngrid=970 \nLeft mul cvi 15,
  r=\rWire,
  fillcolor=wireColor,
  incolor=wireColor
}

\pagestyle{empty}

\begin{document}

\begin{figure}[htbp]
 \centering
  \begin{pspicture}(-5,-5)(5,5)
   \psset{%
     algebraic,
     viewpoint=20 5 10 rtp2xyz,
     lightsrc=20 60 60 rtp2xyz,
     Decran=30,
     solidmemory,
     action=none,
     grid=false
   }
   %%--------- Core ----------
   \psSolid[object=anneau,h=1.0,R=4,r=2.5,ngrid=4,RotZ=90,RotY=45,RotX=90,
     fillcolor=coreColor,name=core]
   %%--------- Wire ----------
   % Left
   \defFunction{heliceA}(t){\rHelix*cos(\factor*t)}{\rHelix*sin(\factor*t)}%
     {t/\nLeft}
   \wire[function=heliceA,range=0 Pi \nLeft mul,name=wireA](0,-2.25,-1.5)
   % Right
   \defFunction{heliceB}(t){\rHelix*cos(\factor*t)}{-\rHelix*sin(\factor*t)}%
     {t/\nRight}
   \wire[function=heliceB,range=0 Pi \nRight mul,name=wireB](0,2.25,-1.5)
   %%------- Assembly --------
   \psSolid[object=fusion,base=core wireA wireB,action=draw**]
  \end{pspicture}
\end{figure}

\end{document}

, I get this following error:

Code: Select all

! Undefined control sequence.
\@tempb ->t/\nLeft 
                   
l.56      {t/\nLeft}

[cgnieder]

I believe you should use it as

Code: Select all

t/nLeft

i.e. without the backslash.

Regards

[CrazyHorse]

Code: Select all

\pstVerb{
  /nLeft 2 \lWind mul \factor div def
  /nRight 2 \rWind mul \factor div def
}

\newpsobject{wire}{psSolid}{%
  object=courbe,
   % Choose max(\nRight,\nLeft) -- the fewer windings, the larger
   % the constant multiplied by max(\nRight,\nLeft)
  ngrid=970 \nLeft mul cvi 15,

, I get this following error:

Code: Select all

! Undefined control sequence.
\@tempb ->t/\nLeft 
                   
l.56      {t/\nLeft}

Only in \pstVerb with a backslash.

ngrid=970 nLeft mul cvi 15,

[svend_tveskaeg]

Thank you, Herbert and Clemens!

Can you tell me when to use \def and when to use \pstVerb?

Update
And thank you, Stefan.

[CrazyHorse]

Can you tell me when to use \def and when to use \pstVerb?

\def defines a TeX macro, used as \...
\pstVerb defines PostScript functions, used _only_ in PS expressions

Code: Select all

\pstVerb{ /ePow { 2.728 exch exp } def }

now you can use something like

Code: Select all

ngrid = 1 3 ePow,

[svend_tveskaeg]

I see. Thank you very much.