% $Id: xyatip.mf,v 3.3 1996/12/19 04:05:28 krisrose Exp $
%
% Generate upper arrow tips for Xy-pic.
% Copyright (c) 1994-1996  Kristoffer H. Rose  <kris@diku.dk>
%
% This file is part of the Xy-pic macro package.
%
% The Xy-pic macro package is free software; you can redistribute it and/or
% modify it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2 of the License, or (at your
% option) any later version.
%
% The Xy-pic macro package is distributed in the hope that it will be
% useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
% Public License for more details.
%
% You should have received a copy of the GNU General Public License along
% with this macro package; if not, write to the Free Software Foundation,
% Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
% _________________________________________________________________________
%
% CONTENTS: Arrow tips *pointing* in all directions.  With zero bounding box
% placed at the tip; note most of the ink goes on the opposite side of where
% the tip points.
%
% Generates the half of the tip that is upper when pointing right.
% _________________________________________________________________________
%
pickup pencircle scaled segw; char_pen := savepen;
%
% chartowards makes char cc a tip pointing towards (dx,dy)...
%
def chartowards(expr cc,dx,dy) =
 beginchar(cc,0,0,0);
  a := angle(dx,dy);
  z0 = (tipo,0) rotated a; 		% tip of tip
  z1 = (-segl,0) rotated a;		% center of tail
  z2 = (-segl,1/2 segx) rotated a;	% tail ends
  z3 = curvature [z1,z2];		% tail directions
  pickup char_pen; draw z2..{-z3}z0;
  penlabels(0,1,2,3);
 endchar
enddef;

% TESTING...we redefine openit because the characters extend far to the
% left of the bounding box!
%
def openit = openwindow currentwindow
 from origin to (screen_cols,screen_rows) at (-200,300) enddef;

% GENERATE...
%
input xyd

bye.
%
% $Log: xyatip.mf,v $
% Revision 3.3  1996/12/19 04:05:28  krisrose
% New for this maintenance release.
%
% Based on xyatip10.mf,v 3.0 1995/07/07 20:14:21 kris Exp