How long is a path? Alas currentdash is silent

Newsgroups	comp.lang.postscript
Date	2016-04-05 16:34 -0700
Message-ID	<7d687ea2-4b38-408d-be5f-e35d730137eb@googlegroups.com> (permalink)
Subject	How long is a path? Alas currentdash is silent
From	jdaw1 <jdawiseman@gmail.com>

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I would like to know how long is a path, in the current transformation matrix.

My plan, which has failed, was as follows. 

% ... arc ... curveto ... curveto etc closepath
[9999 dup] 0 setdash
gsave nulldevice stroke currentdash grestore exch pop
% The number on the stack, I had hoped, would be the length of the path. 
% Alas it is 0.0.

This fails, probably because, from PLRM3 p667:
> Each subpath of a path is treated independently; the dash pattern is restarted and the offset reapplied at the beginning of each subpath.

And even without the terminating closepath, currentdash returns 0.0.

The other obvious means of proceeding would be to do lots of arithmetic in three of the four code parameters passed to pathforall. What a painful slog. 

Please, has anybody a better plan?

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How long is a path? Alas currentdash is silent jdaw1 <jdawiseman@gmail.com> - 2016-04-05 16:34 -0700
  Re: How long is a path? Alas currentdash is silent tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2016-04-05 21:45 -0400
    Re: How long is a path? Alas currentdash is silent luser- -droog <mijoryx@yahoo.com> - 2016-04-05 19:09 -0700
      Re: How long is a path? Alas currentdash is silent jdaw1 <jdawiseman@gmail.com> - 2016-04-06 01:26 -0700
        Re: How long is a path? Alas currentdash is silent jdaw1 <jdawiseman@gmail.com> - 2016-04-06 05:07 -0700
          Re: How long is a path? Alas currentdash is silent Scott Hemphill <hemphill@hemphills.net> - 2016-04-06 11:40 -0400
            Re: How long is a path? Alas currentdash is silent jdaw1 <jdawiseman@gmail.com> - 2016-04-06 09:52 -0700
              Re: How long is a path? Alas currentdash is silent sjprouty3765@gmail.com - 2016-04-06 12:05 -0700
                Re: How long is a path? Alas currentdash is silent jdaw1 <jdawiseman@gmail.com> - 2016-04-06 14:55 -0700
              Re: How long is a path? Alas currentdash is silent Scott Hemphill <hemphill@hemphills.net> - 2016-04-06 17:12 -0400
                Re: How long is a path? Alas currentdash is silent jdaw1 <jdawiseman@gmail.com> - 2016-04-06 14:34 -0700
        Re: How long is a path? Alas currentdash is silent Scott Hemphill <hemphill@hemphills.net> - 2016-04-06 11:35 -0400
          Re: How long is a path? Alas currentdash is silent jdaw1 <jdawiseman@gmail.com> - 2016-04-06 09:38 -0700
  Re: How long is a path? Alas currentdash is silent jdaw1 <jdawiseman@gmail.com> - 2016-04-07 01:39 -0700
  Re: How long is a path? Alas currentdash is silent Carlos <angus@quovadis.com.ar> - 2016-04-08 15:04 +0200
    Re: How long is a path? Alas currentdash is silent jdaw1 <jdawiseman@gmail.com> - 2016-04-08 14:32 -0700
      Re: How long is a path? Alas currentdash is silent Carlos <angus@quovadis.com.ar> - 2016-04-09 01:19 +0200
    Re: How long is a path? Alas currentdash is silent jdaw1 <jdawiseman@gmail.com> - 2016-04-08 14:57 -0700
      Re: How long is a path? Alas currentdash is silent Carlos <angus@quovadis.com.ar> - 2016-04-09 01:31 +0200

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