What was that 'rounding paths' metafun(?) function again?

What was that 'rounding paths' metafun(?) function again?

[Gerben Wierda]

I think I saw a function in MetaFun somehwre that you could give a ‘hard’ path, i.e. (0,0) -- (0,1) — (1,1) and it would become a path with nicely rounded (part of a circle) corners (still straight lines), but I can’t find it anymore. I wrote my own, but it is giving me headaches so I’d like to find something that is better than what I produce.

G
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Re: What was that 'rounding paths' metafun(?) function again?

[Wolfgang Schuster]

Gerben Wierda schrieb am 05.04.2020 um 12:31:
> I think I saw a function in MetaFun somehwre that you could give a ‘hard’ path, i.e. (0,0) -- (0,1) — (1,1) and it would become a path with nicely rounded (part of a circle) corners (still straight lines), but I can’t find it anymore. I wrote my own, but it is giving me headaches so I’d like to find something that is better than what I produce.

You you mean "cornered ..." or "smoothed ..."?

Wolfgang
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Re: What was that 'rounding paths' metafun(?) function again?

[Gerben Wierda]

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Yes, I meant cornered.

But it turns out it works worse in my case, I get paths with hundreds of segments and a run that goes amok. But that made me find a mistake in my code and now I’m using my own again and it works fine:

vardef softenPath( expr hardPath) =
  save softPath; path softPath;
  save len; len := length hardPath;
  save rounding; rounding := 5;
  save i;
  for i=0 upto len:
    if (i=0):
      % first pair
      softPath := point i of hardPath;
    elseif (i=len):
      % lastpair
      softPath := softPath -- point i of hardPath;
    else:
      % intermediate pair
      save subOne; path subOne; subOne := subpath(i-1, i) of hardPath;
      save subTwo; path subTwo; subTwo := subpath(i, i+1) of hardPath;
      save lenOne; numeric lenOne; lenOne := arclength subOne;
      save lenTwo; numeric lenTwo; lenTwo := arclength subTwo;
      save pointOne, pointTwo; pair pointOne, pointTwo;
      pointOne := point (arctime (lenOne-rounding) of subOne) of subOne;
      pointTwo := point (arctime rounding of subTwo) of subTwo;
      save dirOne, dirTwo; pair dirOne, dirTwo;
      dirOne := direction (arctime (lenOne-rounding) of subOne) of subOne;
      dirTwo := direction (arctime (rounding) of subTwo) of subTwo;
      softPath := softPath -- pointOne{dirOne} .. {dirTwo}pointTwo;
    fi
  endfor;
  softPath
enddef;

Fixed rounding of 5bp, but that is easy to change.

> On 5 Apr 2020, at 12:37, Wolfgang Schuster <wolfgang.schuster.lists@gmail.com> wrote:
> 
> Gerben Wierda schrieb am 05.04.2020 um 12:31:
>> I think I saw a function in MetaFun somehwre that you could give a ‘hard’ path, i.e. (0,0) -- (0,1) — (1,1) and it would become a path with nicely rounded (part of a circle) corners (still straight lines), but I can’t find it anymore. I wrote my own, but it is giving me headaches so I’d like to find something that is better than what I produce.
> 
> You you mean "cornered ..." or "smoothed ..."?
> 
> Wolfgang


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Re: What was that 'rounding paths' metafun(?) function again?

[Keith McKay]

Would sections 1.3, 1.18, 2.5 and 2.6 in the Metafun manual help?

Keith

On 05/04/2020 11:31, Gerben Wierda wrote:
> I think I saw a function in MetaFun somehwre that you could give a ‘hard’ path, i.e. (0,0) -- (0,1) — (1,1) and it would become a path with nicely rounded (part of a circle) corners (still straight lines), but I can’t find it anymore. I wrote my own, but it is giving me headaches so I’d like to find something that is better than what I produce.
>
> G
> ___________________________________________________________________________________
> 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://context.aanhet.net
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> wiki     : http://contextgarden.net
> ___________________________________________________________________________________
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Re: What was that 'rounding paths' metafun(?) function again?

[Gerben Wierda]

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> On 5 Apr 2020, at 15:24, Keith McKay <mckaymeister@gmail.com> wrote:
> 
> Would sections 1.3, 1.18, 2.5 and 2.6 in the Metafun manual help?

I used what is in 1.3 (though I actually used Peter Grogono’s PDF MetaPost: A Reference Manual <https://users.encs.concordia.ca/~grogono/Writings/mpref.pdf> which I find the best educational document about plain METAPOST so far).

1.18 was what I was looking for but did not work in my situation (don’t know why, but it exploded). I fixed another issue (calling cornering on top of cornering when doing recursion) and that made my own macro behave perfectly civilised.

I had looked at 2.5 and 2.6 but this was not required (nor of any use).

G

> 
> Keith
> 
> On 05/04/2020 11:31, Gerben Wierda wrote:
>> I think I saw a function in MetaFun somehwre that you could give a ‘hard’ path, i.e. (0,0) -- (0,1) — (1,1) and it would become a path with nicely rounded (part of a circle) corners (still straight lines), but I can’t find it anymore. I wrote my own, but it is giving me headaches so I’d like to find something that is better than what I produce.
>> 
>> G
>> ___________________________________________________________________________________
>> 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://context.aanhet.net
>> archive  : https://bitbucket.org/phg/context-mirror/commits/
>> wiki     : http://contextgarden.net
>> ___________________________________________________________________________________
> ___________________________________________________________________________________
> 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://context.aanhet.net
> archive  : https://bitbucket.org/phg/context-mirror/commits/
> wiki     : http://contextgarden.net
> ___________________________________________________________________________________


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