##
## "VIEW", a data viewing program,
##   Copyright (C) 1987, 1990 California Institute of Technology.
##   Original authors: Dave Gillespie, port by Rick Koshi
##   Unix Port Maintainer: John Lazzaro
##   Maintainers's address: lazzaro@hobiecat.cs.caltech.edu;
##                          CB 425/ CU Boulder/Boulder CO 91125. 
##
##
##This program 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 (Version 1, Feb 1989).
##
##This program 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 program; see the file ../COPYING.  If not, write to
##the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 
##
##
define trapezoid out = curve
   local int = 0
   local maxstep = cvlen(curve)
   local i
   echo $maxstep
   for i = 1 : (maxstep - 1) : 1
     int = int + 0.5*(cvidx(curve,i+1) + cvidx(curve,i))/   \\
            (cvidx(curve+'_x',i+1) - cvidx(curve+'_x',i))
     echo $int
   endfor
   $out = int
   echo $int
enddef