[NTG-context] Fwd: Fuzzy lines

12 May 2021

      ---------- Forwarded message ---------
De: Jairo A. del Rio 
Date: mié, 12 de may. de 2021 a la(s) 14:08
Subject: Re: [NTG-context] Fuzzy lines
To: mailing list for ConTeXt users 

El mié, 12 de may. de 2021 a la(s) 13:03, Henning Hraban Ramm (
texml@fiee.net) escribió:
...
Hi Jairo,
thank you for the suggestion.
...
Am 11.05.2021 um 14:56 schrieb Jairo A. del Rio 
For simple pens, you may define your own (section 9.7 of MetaPost
manual).
Unfortunately, pens don’t work as patterns but only as outlines.
...
For complicated strokes, something along these lines could be useful as
a starting point (I'm not taking cyclic paths in consideration, btw). I did
something similar with duck footprints some weeks ago:
%Sorry for the ugly code...
\starttext
\startMPpage
%Unit size
numeric u; u := 1mm;
%In a picture you are able to include everything, kinda
picture Pluma;
Pluma := image(
      for i = 1 upto 5:
              for j = 1 upto 5:
                      draw (i,j) randomized 1;
              endfor
      endfor
);
Unfortunately, that’s the same pattern over and over.
The randomization is only applied once.
Good for footprints, bad for fuzzy patterns.
You only need to move "randomized" at the drawing stage:

\starttext

\startMPpage

numeric u; u := 1mm;

picture Pluma;

Pluma := image(

for i = 1 upto 5:

for j = 1 upto 5:

draw (i,j);

endfor

endfor

);

path Camino;

Camino := origin for i = 1 upto 30: .. (u*i, u*sind (12i mod 360)) endfor;

for i = 0 step 1/2 until length Camino:

draw Pluma randomized 1 rotated (90 + angle direction i of Camino)

shifted point i of Camino;

endfor

\stopMPpage

\stoptext

But "randomized" will deform paths. Maybe you want something like this?

\starttext

\startMPpage[align=]

begingroup;

save Rnd; let Rnd = uniformdeviate;

numeric u; u := 3mm;

picture Pluma;

Pluma := image(

for i = 1 upto 5:

for j = 1 upto 5:

fill fullcircle shifted (i,j); %try fulltriangle or another shape

endfor

endfor

);

path Camino;

Camino := origin for i = 1 upto 30: .. u*i*left endfor;

for i = 0 step 1/2 until length Camino:

draw image(

for x within Pluma:

fill pathpart x %Assuming our image only contains cyclic paths

scaled (1+Rnd 1)

shifted (1/2dir Rnd 360)

withcolor hsvtorgb(6round(Rnd 60),9/10,1); %Colors just because they look
cute

endfor

) rotated (90 + angle direction i of Camino)

shifted point i of Camino;

endfor

endgroup;

\stopMPpage

\stoptext
...
%Simple curve
...
path Camino;
Camino := origin for i = 1 upto 30: .. (u*i, u*sind (12i mod 360))
endfor;
%Strokes
for i = 0 step 1/2 until length Camino:
      draw Pluma rotated (90 + angle direction i of Camino)
              shifted point i of Camino;
endfor
Since I have more or less straight lines but of different length, the "one
pattern per 1/n path segment" doesn’t work for me. I could try to construct
my paths differently.
You only need to use fractions, i.e., "for 0 step 1/n until 1: ... endfor"
if you work with straight lines defined using only two points. In the
example above I made one from more than two points just for ease of
manipulation. With examples and feedback from the mailing list, you might
define your own function using the new Metafun interface for LMTX.
...
Hraban
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Jairo