From mboxrd@z Thu Jan  1 00:00:00 1970
X-Msuck: nntp://news.gmane.io/gmane.comp.tex.context/4913
Path: main.gmane.org!not-for-mail
From: "Denis B. Roegel" <Denis.Roegel@loria.fr>
Newsgroups: gmane.comp.tex.context
Subject: Re: Labeling a tree with MetaObj.
Date: Mon, 2 Jul 2001 21:23:00 +0200
Sender: owner-ntg-context@let.uu.nl
Message-ID: <20010702212300.A13559@bar.loria.fr>
References: <974796191.20010630192115@bigfoot.com> <Pine.GSO.4.05.10107021102590.21094-101000@sumak>
NNTP-Posting-Host: coloc-standby.netfonds.no
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Trace: main.gmane.org 1035395546 29794 80.91.224.250 (23 Oct 2002 17:52:26 GMT)
X-Complaints-To: usenet@main.gmane.org
NNTP-Posting-Date: Wed, 23 Oct 2002 17:52:26 +0000 (UTC)
Cc: ntg-context@ntg.nl
Original-To: Tarik Kara <ktarik@Bilkent.EDU.TR>
In-Reply-To: <Pine.GSO.4.05.10107021102590.21094-101000@sumak>; from ktarik@Bilkent.EDU.TR on Mon, Jul 02, 2001 at 11:11:07AM +0300
Xref: main.gmane.org gmane.comp.tex.context:4913
X-Report-Spam: http://spam.gmane.org/gmane.comp.tex.context:4913

On Mon, Jul 02, 2001 at 11:11:07AM +0300, Tarik Kara wrote:
> I would like to draw the tree diagram shown at the attachement with
> MetaObj. I can label the terminal nodes and the edge labeled "o". But I
> had no luck with the nodes label "1", "2", and the other edges. Any
> succestions is appreciated. Thanks in advance.

Below is a solution. I didn't bother to get the same dimensions
as you, though.

I have used the (unfortunately) undocumented treeroot macro, which I should
actually extend a bit.

I know this solution looks complex and that's why a TeX (or ConTeXt) interface
is really needed! :-)

Feel free to post other queries. I'll use them for the next version
of the metaobj manual. However, I am not sure everybody is interested
in this group, so it might be a better idea to post the questions
on the metafont/metapost mailing list, even though I doubt anybody else
than I will answer for some time...

Denis

% Example requested by Tarik Kara.
% A useful inspiration was the figure on page 109 of the metaobj manual.
% D. Roegel, 2 July 2001
input metaobj

setCurveDefaultOption("arrows","draw");
setObjectDefaultOption("Tree")("hideleaves")(true);

def mytc=new_Circle_("")("filled(true)") enddef;

labeloffset:=2bp; % 3bp is the default in plain.mp 

beginfig(1);
  t:=T_(mytc)(mytc,T_(mytc)(mytc,mytc)("hbsep(2cm)"))("hbsep(2cm)");
  Obj(t).c=origin;
  % |ObjLabel| should appear after an object is positionned (this is not
  % clearly stated in the manual); one can always move the object afterwards;
  % this constraint appears when |ObjLabel| is used on subtrees, since
  % |ObjLabel| temporarily attaches the object; when it unties it, links
  % to the embedding object(s) are lost.
  ObjLabel.ntreepos(Obj(t))(1)(btex $(0,2)$ etex) "labcard(s)";
  ObjLabel.ntreepos(Obj(t))(2,1)(btex $(-1,0)$ etex) "labcard(s)";
  ObjLabel.ntreepos(Obj(t))(2,2)(btex $(1,1)$ etex) "labcard(s)";
  % the |treeroot| function should also work for an empty second argument,
  % but this is currently not the case, so one has to use |obj| and |root|
  % in order to dig into the object; it will be corrected in the next version
  % of metaobj.
  ObjLabel.obj(Obj(t)root)(btex $1$ etex) "labcard(n)";
  ObjLabel.treeroot(Obj(t))(2)(btex $2$ etex) "labcard(ne)";
  ObjLabel.Obj(t)(btex $o$ etex) "labpathid(1)", "labdir(lft)";
  ObjLabel.Obj(t)(btex $e$ etex) "labpathid(2)", "labdir(rt)";
  ObjLabel.ntreepos(Obj(t))(2)(btex $f$ etex) "labpathid(1)", "labdir(lft)";
  ObjLabel.ntreepos(Obj(t))(2)(btex $a$ etex) "labpathid(2)", "labdir(rt)";
  draw_Obj(t);
endfig;

end