From: Thangalin via ntg-context <ntg-context@ntg.nl>
To: Alan Braslau <alan.braslau@icloud.com>
Cc: Thangalin <thangalin@gmail.com>,
mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: atan2 function
Date: Fri, 14 Oct 2022 16:09:41 -0700 [thread overview]
Message-ID: <CAANrE7rGgd9-et98cLoBtVyQO=94ZMVyhJOtHYycjM8RULgdEA@mail.gmail.com> (raw)
In-Reply-To: <20221014164212.3d187bb2@boo.my.domain>
That's certainly tighter, thank you, Alan.
Would making the conditional part of the API be useful to others?
Cheers!
On Fri, Oct 14, 2022 at 3:42 PM Alan Braslau <alan.braslau@icloud.com> wrote:
>
> On Fri, 14 Oct 2022 11:59:49 -0700
> Thangalin <thangalin@gmail.com> wrote:
>
> > I don't think an atantwo is needed. I *thought* I had read somewhere
> > that atan( y, x ) was equivalent to calling atan2 in Lua. Ensuring
> > there's no breakage when x == y would be nice, though. It was a little
> > surprising to see angle return degrees rather than radians, but it
> > does simplify my code:
> >
> > dc := vbc - vac;
> > dr := vbr - var;
> > vi := 0;
> >
> > if not( dc == dr ):
> > vi := round( angle( dc, dr ) / 60 );
> > fi;
> >
> > % Compute the direction towards the first segment (to vertex of
> > an edge). vangle := vi * 60 * pi / 180;
> >
> > Even simpler would be:
> >
> > dc := vbc - vac;
> > dr := vbr - var;
> > vi := round( angle( dc, dr ) / 60 ); % returns 0 when dc == dr
> >
> > % Compute the direction towards the first segment (to vertex of
> > an edge). vangle := vi * 60 * pi / 180;
> >
> > Or accepting a third argument as the return value in the special case:
> >
> > vi := round( angle( dc, dr, 0 ) / 60 ); % returns 0 when dc ==
> > dr
> >
> > Cheers!
>
> vi := if (dc = dr) : 0 else : round (angle(dc,dr)/60) fi ;
>
> Alan
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next prev parent reply other threads:[~2022-10-14 23:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-13 5:40 Thangalin via ntg-context
2022-10-13 6:42 ` Max Chernoff via ntg-context
2022-10-13 19:51 ` Thangalin via ntg-context
2022-10-14 0:35 ` Max Chernoff via ntg-context
2022-10-14 8:07 ` Hans Hagen via ntg-context
2022-10-14 14:40 ` Alan Braslau via ntg-context
2022-10-14 18:59 ` Thangalin via ntg-context
2022-10-14 22:42 ` Alan Braslau via ntg-context
2022-10-14 23:09 ` Thangalin via ntg-context [this message]
2022-10-15 1:22 ` Alan Braslau via ntg-context
2022-10-14 12:26 ` Alan Braslau via ntg-context
2022-10-14 12:58 ` Taco Hoekwater via ntg-context
2022-10-14 13:05 ` luigi scarso via ntg-context
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