--- /dev/null
+## Copyright (C) 2007-2012 David BAteman
+##
+## This file is part of Octave.
+##
+## Octave 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 3 of the License, or (at
+## your option) any later version.
+##
+## Octave 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 Octave; see the file COPYING. If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} contour3 (@var{z})
+## @deftypefnx {Function File} {} contour3 (@var{z}, @var{vn})
+## @deftypefnx {Function File} {} contour3 (@var{x}, @var{y}, @var{z})
+## @deftypefnx {Function File} {} contour3 (@var{x}, @var{y}, @var{z}, @var{vn})
+## @deftypefnx {Function File} {} contour3 (@dots{}, @var{style})
+## @deftypefnx {Function File} {} contour3 (@var{h}, @dots{})
+## @deftypefnx {Function File} {[@var{c}, @var{h}] =} contour3 (@dots{})
+## Plot level curves (contour lines) of the matrix @var{z}, using the
+## contour matrix @var{c} computed by @code{contourc} from the same
+## arguments; see the latter for their interpretation. The contours are
+## plotted at the Z level corresponding to their contour. The set of
+## contour levels, @var{c}, is only returned if requested. For example:
+##
+## @example
+## @group
+## contour3 (peaks (19));
+## hold on
+## surface (peaks (19), "facecolor", "none", "EdgeColor", "black");
+## colormap hot;
+## @end group
+## @end example
+##
+## The style to use for the plot can be defined with a line style @var{style}
+## in a similar manner to the line styles used with the @code{plot} command.
+## Any markers defined by @var{style} are ignored.
+##
+## The optional input and output argument @var{h} allows an axis handle to
+## be passed to @code{contour} and the handles to the contour objects to be
+## returned.
+## @seealso{contourc, patch, plot}
+## @end deftypefn
+
+function [c, h] = contour3 (varargin)
+
+ [xh, varargin, nargin] = __plt_get_axis_arg__ ("contour3", varargin{:});
+
+ oldh = gca ();
+ unwind_protect
+ axes (xh);
+ newplot ();
+ [ctmp, htmp] = __contour__ (xh, "auto", varargin{:});
+ unwind_protect_cleanup
+ axes (oldh);
+ end_unwind_protect
+
+ if (! ishold ())
+ set (xh, "view", [-37.5, 30],
+ "xgrid", "on", "ygrid", "on", "zgrid", "on");
+ endif
+
+ if (nargout > 0)
+ c = ctmp;
+ h = htmp;
+ endif
+
+endfunction
+
+%!demo
+%! clf
+%! contour3 (peaks (19));
+%! hold on
+%! surface (peaks (19), "facecolor", "none", "edgecolor", "black")
+%! colormap hot
+%! axis tight
+%! zlim auto
+%! hold off
+%! box off