Hi Aditya,
Following your explanations in
https://adityam.github.io/context-blog/post/new-metafun-interface/
I wrote an environment in order to display the graph of a function on a grid
which can be adapted to each case.
Assuming that I have an MPinstance named GridAxis (for example) which can
dispaly a grid and axes, how can I call it and write a line such as
draw function (1,"x","x*x/4 - 2.5",xmin,xmax,.001) scaled sx ;
without changing the part whichh is included in \startMPdefinitions, in oder to
draw the above function on that grid ?
Thanks for your help: Otared
PS: Here is my definition of GridAxis (I guess many parts of it could be better
written…)
\defineMPinstance[GridAxis]
[
format=metafun,
extensions=yes,
initializations=yes,
method=double,
]
\startMPdefinitions{GridAxis}
def GridAxisPlot = applyparameters "GridAxisPlot" "do_GridAxisPlot" enddef ;
presetparameters "GridAxisPlot" [
xmin = -2.5, xmax = 2.5,
ymin = -2.5, ymax = 2.5,
dx = 1, dy = 1,
sx = 5mm, sy = 5mm,
scale = 0.5,
grid = true,
xaxisnumbers = true,
yaxisnumbers = true,
showmyorigin = true,
style = "\switchtobodyfont[8pt]",
];
vardef do_GridAxisPlot =
image (
pushparameters "GridAxisPlot";
newnumeric xmin, xmax, ymin, ymax;
xmin := getparameter "xmin";
xmax := getparameter "xmax";
ymin := getparameter "ymin";
ymax := getparameter "ymax";
newnumeric sx, sy;
sx := getparameter "sx";
sy := getparameter "sy";
newnumeric dx, dy;
dx := getparameter "dx";
dy := getparameter "dy";
newpath xaxis, yaxis;
xaxis := (xmin*sx, 0) -- (xmax*sx, 0) ;
yaxis := (0, ymin*sy) -- (0, ymax*sy) ;
newpath xtick, ytick;
xtick := (-0.1sx, 0) -- (0.1sx, 0);
ytick := (0, -0.1sy) -- (0, 0.1sy);
newstring style;
style := getparameter "style";
pickup pencircle scaled .1mm ;
newboolean grid;
grid := getparameter "grid";
newboolean xaxisnumbers ;
xaxisnumbers := getparameter "xaxisnumbers" ;
newboolean yaxisnumbers ;
yaxisnumbers := getparameter "yaxisnumbers" ;
for x = dx step dx until xmax :
if grid :
draw yaxis shifted (x*sx, 0) withcolor 0.75white ;
fi
draw ytick shifted (x*sx, 0);
if xaxisnumbers :
label.bot(style & decimal x, (x*sx, 0));
fi
endfor
newboolean showmyorigin ;
showmyorigin := getparameter "showmyorigin" ;
if showmyorigin :
label.lrt(style & "0", origin) ;
fi
for x = -dx step -dx until xmin :
if grid :
draw yaxis shifted (x*sx, 0) withcolor 0.75white;
fi
draw ytick shifted (x*sx, 0);
if xaxisnumbers :
label.bot(style & decimal x, (x*sx, 0));
fi
endfor
for y = dy step dy until ymax :
if grid :
draw xaxis shifted (0, y*sy) withcolor 0.75white;
fi
draw xtick shifted (0, y*sy);
if yaxisnumbers :
label.lft(style & decimal y, (0, y*sy));
fi
endfor
for y = -dy step -dy until ymin :
if grid :
draw xaxis shifted (0, y*sy) withcolor 0.75white;
fi
draw xtick shifted (0, y*sy);
if yaxisnumbers :
label.lft(style & decimal y, (0, y*sy));
fi
endfor
drawarrow xaxis;
drawarrow yaxis;
label.rt( style & "$x$", (xmax*sx, 0));
label.top(style & "$y$", (0, ymax*sy));
newpair p ;
newnumeric scale;
scale := getparameter "scale" ;
popparameters;
)
enddef;
\stopMPdefinitions
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