--- a/scripts/ChangeLog	Sun Nov 25 04:32:24 2007 +0000
+++ b/scripts/ChangeLog	Mon Nov 26 18:14:52 2007 +0000
@@ -1,3 +1,8 @@
+2007-11-26  Kai Habel  <kai.habel@gmx.de>
+
+	* plot/cylinder.m: New function.
+	* plot/Makefile.in (SOURCES): Add it to the list.
+
 2007-11-14  Michael Goffioul  <michael.goffioul@gmail.com>
 
 	* plot/patch.m: Handle arg may also be hggroup object.

--- a/scripts/plot/Makefile.in	Sun Nov 25 04:32:24 2007 +0000
+++ b/scripts/plot/Makefile.in	Mon Nov 26 18:14:52 2007 +0000
@@ -76,6 +76,7 @@
   contour.m \
   contourc.m \
   contourf.m \
+  cylinder.m \
   drawnow.m \
   errorbar.m \
   figure.m \

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/plot/cylinder.m	Mon Nov 26 18:14:52 2007 +0000
@@ -0,0 +1,95 @@
+## Copyright (C) 2007 Michael Goffioul, Kai Habel
+##
+## 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} {} cylinder
+## @deftypefnx {Function File} {} cylinder (@var{r})
+## @deftypefnx {Function File} {} cylinder (@var{r}, @var{n})
+## @deftypefnx {Function File} {[@var{x}, @var{y}, @var{z}] =} cylinder (@dots{})
+## @deftypefnx {Function File} {} cylinder (@var{ax}, @dots{})
+## Generates three matrices in @code{meshgrid} format, such that
+## @code{surf (@var{x}, @var{y}, @var{z})} generates a unit cylinder.
+## The matrices are of size @code{@var{n}+1}-by-@code{@var{n}+1}. 
+## @var{r} is a vector containing the radius along the z-axis.
+## If @var{n} or @var{r} are omitted then default values of 20 or [1 1]
+## are assumed.
+##
+## Called with no return arguments, @code{cylinder} calls directly
+## @code{surf (@var{x}, @var{y}, @var{z})}. If an axes handle @var{ax} is passed
+## as the first argument, the surface is plotted to this set of axes.
+##
+## Examples:
+## @example
+## disp("plotting a cone")
+## [X, Y, Z] = cylinder(10:-1:0,50);
+## surf(X,Y,Z);
+## @end example
+## @seealso{sphere}
+## @end deftypefn
+
+function [xx,yy,zz] = cylinder (varargin)
+
+  nargs = nargin;
+  args = varargin;
+
+  if (nargs > 1 && isscalar (varargin{1}) && ishandle (varargin{1}))
+    if (! strcmp (get (varargin{1}, "type"), "axes"))
+      error ("cylinder: expecting first argument to be an axes object");
+    endif
+    ax = h;
+    nargs--;
+    args(1) = [];
+  else
+    ax = gca();
+  endif
+
+  if (nargs == 0)
+    n = 20;
+    r = [1 1];
+  elseif (nargs == 1)
+    n = 20;
+    r = args{1};
+  elseif (nargs == 2)
+    r = args{1};
+    n = args{2};
+  else
+    print_usage();
+  endif
+
+  if (length(r) < 2)
+    error("cylinder: length(r) must be larger than 2.")
+  endif
+
+  phi = linspace(0, 2*pi, n+1);
+  idx = 1:length(r);
+  [phi, idx] = meshgrid(phi, idx);
+  z = (idx - 1) / (length(r) - 1);
+  r = r(idx);
+  [x, y] = pol2cart(phi, r);
+
+  if (nargout > 0)
+    xx = x;
+    yy = y;
+    zz = z;
+  else
+    axes(ax);
+    surf (x, y, z);
+  endif
+
+endfunction