Hi Lukas.
A year ago, I tried something similar when I wanted to make an animated pdf images.
With using Lua, I can not handle eventually, but for inspiration attach a piece of code that demonstrates how get into buffer some parameters without Lua code. Maybe it inspires you in your solution.

I apologize for dirty code, but I cutting it from my old library and my context application. I did not clean it and I did not translate into English. For those interested I can possibly do.

Jarda Hajtmar

Here is my example:


\usemodule[tikz]
\usemodule[pgfplots]

%\define[1]\ListEntry{#1\par}
%\processcommalist[one,two,{three,four}]\ListEntry
%\processseparatedlist[one*two*three,four][*]\ListEntry
\def\zpracujparametry[#1]#2%
{\processcommalist[#1]{\nastavparametr{#2}}}
% Použití:
% \zpracujparametry[1,5,3.7,4,5,8,9,11]{
% \getbuffer[funkce1]
% \page
% }


\def\ZPRACUJPARAMETRY#1[#2]#3%
{\processseparatedlist[#2][#1]{\nastavparametr{#3}}}
% Použití:
% \ZPRACUJPARAMETRY{znak separátoru}[1,5,3.7,4,5,8,9,11]{
% \getbuffer[funkce1]
% \page
% }


\def\pmparametr#1=$#2${\global\def\parametr{#1}\global\def\mparametr{#2}}

\def\nastavparametry#1#2{\pmparametr#2\global\def\pparametr{#2}#1}%

\def\zpracujdvojparametry[#1]#2%
{\processcommalist[#1]{\nastavparametry{#2}}}
% Použití:
% \zpracujdvojparametry[1=$a$,5=$b$,3.7=$c$,4=$d$,5=$e$,8=$f$,9=$g$,11=$h$]{
% \getbuffer[funkce1]
% \page
% }

\def\ZPRACUJDVOJPARAMETRY#1[#2]#3%
{\processseparatedlist[#2][#1]{\nastavparametry{#3}}}
% Použití:
% \ZPRACUJDVOJPARAMETRY{;}[1=$a$;5=$b$;3.7=$c$;4=$d$;5=$e$;8=$f$;9=$g$;11=$h$]{
% \getbuffer[funkce1]
% \page
% }



\startbuffer[goniometrickefunkce]
\def\function{cos(deg(\x+\parametr))}
\def\permfunction{cos(deg(\x))}
\def\permfunctiontwo{sin(deg(\x))}
\startTEXpage
\starttikzpicture[scale=1]
\tikzset{style={font=\ssxx}}
\startaxis
[xmin=-1.6,
xmax=10,
domain=-1.6:10,
ymin=-1.1,
ymax=1.1,
width=\textwidth,
height=0.3\textwidth,
axis x line=middle,
axis y line=middle,
axis equal=true,
xlabel=$x$,
ylabel=$y$,
samples=600,
clip=true,
xtick={0},
ytick={-1,0,1},
grid=major,
extra x ticks={-1.57,1.57,3.14,4.71,6.28,7.85,9.42,10.99,12.57}, extra x tick labels={$-\frac{\pi}{2}$,$\frac{\pi}{2}$,$\pi$,$3\!\frac{\pi}{2}$,$2\pi$,$5\!\frac{\pi}{2}$,$3\pi$},
title={{\framed[frame=off,height=1cm]{\blue $\ssb f\!:\ y=\cos{(x \mparametr )}$}}},
]

\addplot[color=yellow, line width=0.5pt] {\permfunctiontwo};
\addplot[color=red, line width=0.5pt] {\permfunction};
\addplot[color=blue, line width=1pt] {\function};

\stopaxis
\stoptikzpicture
\stopTEXpage
\stopbuffer









\starttext

\ZPRACUJDVOJPARAMETRY{*}[1.57=$+\frac{\pi}{2}$*1.047=$+\frac{\pi}{3}$*0.785=$+\frac{\pi}{4}$*0.524=$+\frac{\pi}{6}$*0=$-0$*-0.524=$-\frac{\pi}{6}$*-0.785=$-\frac{\pi}{4}$*-1.047=$-\frac{\pi}{3}$*-1.57=$-\frac{\pi}{2}$*-3.142=$-\pi$*-4.712=$-\frac{3\pi}{2}$*6.28=$-2\pi$]{
\getbuffer[goniometrickefunkce]
\page
}

\stoptext






Dne 15.2.2014 20:38, Lukáš Procházka napsal(a):

Hello,

I just started experimenting with pgfplots package.

I'd have two questions:

1) When plotting/loading a data file: Is it possible to specify the comment mark, which is '#' and '%" by default? I'd need to treat ';' as a comment mark, too.

2) How to pass coordinates of plot points by Lua?

The following code:

----
\usemodule[tikz]
\usemodule[pgfplots]

\startluacode
data = {{5, 15}, {20, 20}, {24, -24}}

plot = function(data)
local str

for i, v in ipairs(data) do
str = (str or "") .. "(" .. v[1] .. "," .. v[2] .. ")"
end

print("Crds=", str)

context(str)
end
\stopluacode

\starttext
\starttikzpicture
\startaxis[]
\addplot[mark=none,color=red] coordinates {(11, 5) (12, 18)}; % THIS PLOT IS OK
\addplot[mark=none,color=red] coordinates {\ctxlua{plot(data)}}; % THIS PLOT HAS NO POINT (?!)
\stopaxis
\stoptikzpicture
\stoptext
----

gives error:

"
...
fonts > fallback modern rm 12pt is loaded
Crds= (5,15)(20,20)(24,-24)
Package pgfplots: Error! Sorry, I could not read the plot coordinates near '(5,15)(20,20)(24,-24)'. Please check for format mistakes.
! Package pgfplots Warning: the current plot has no coordinates (or all have been filtered away)...
"

Any idea from someone more familiar with pgfplots would be appreciated.

TIA.

Best regards,

Lukas

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maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________