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From: Hans Hagen <pragma@wxs.nl>
To: ntg-context@ntg.nl
Subject: Re: passvariable(); path problem
Date: Sun, 06 Oct 2013 00:37:54 +0200	[thread overview]
Message-ID: <525094C2.2030402@wxs.nl> (raw)
In-Reply-To: <525035C2.9000402@gmx.net>

On 10/5/2013 5:52 PM, Peter Rolf wrote:
> I played around with it, but I have problems to understand the format of
> the returned path.
>
> Example:
> % --------
> \setuppagenumber[state=stop]
>
> \starttext
> \nopdfcompression
>
> \startMPpage
>    path p;
>    p:= (20,20){up} .. {down}(200,100);
>    passvariable("path",p);
>    draw p ;
> \stopMPpage
>
> \ctxlua{inspect{metapost.variables["path"]}}
> \stoptext
> % -------
>
> The PDF code of the path is (mainly)
>
> 20.000000 20.000000 m
> 20.000000 190.342880 200.000000 184.016693 200.000000 100.000000 c
>
> "path" contains
>
> table={
>   {
>    { 200, 100, 200, 184.0167, 200, 100 },
>   },
> }
>
> The end point and the second control point are the same, as in the PDF
> code. But how do I calculate the starting point and the first control
> point from the returned values?

something

local prev = nil
for i=1,#path do
     local current = path[i]
     if not prev then
         print(current[1],current[2],"m")
     else
         print(prev[5],prev[6],prev[3],prev[4],current[1],current[2],"c")
     end
     prev = current
end
-- close last to first if needed

 > And is the type of operation (line, curve,..) given by the number of 
values?

by analyzing using thresholds (one can just use "c" always, as "l" is an 
optimization)

Hans

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  reply	other threads:[~2013-10-05 22:37 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-04 12:52 Peter Rolf
2013-10-04 14:15 ` Hans Hagen
2013-10-04 14:47   ` Peter Rolf
2013-10-04 14:59     ` Peter Rolf
2013-10-05 15:52   ` Peter Rolf
2013-10-05 22:37     ` Hans Hagen [this message]
2013-10-06 13:05       ` Peter Rolf
2013-10-06 15:06         ` Hans Hagen
2013-10-07  8:48           ` Peter Rolf
2013-10-07  9:47             ` luigi scarso
2013-10-07 10:03               ` Hans Hagen
2013-10-07 11:02               ` Peter Rolf

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