Mercurial > octave
view scripts/plot/draw/cylinder.m @ 30871:1bddc0ddea74
cylinder.m: Accept scalar radius input for Matlab compatibility.
* NEWS: Announce change in Matlab compatibility section.
* cylinder.m: Check for scalar R input and expand to 2-term form if necessary.
Add input validation for input R. Add BIST tests for input validation.
Rename output variables xx,yy,zz to x,y,z to match documentation. Rename
internal variables x,y,z to xx,yy,zz.
author | Rik <rik@octave.org> |
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date | Tue, 29 Mar 2022 16:15:21 -0700 |
parents | 796f54d4ddbf |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 2007-2022 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## 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 ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {} cylinder ## @deftypefnx {} {} cylinder (@var{r}) ## @deftypefnx {} {} cylinder (@var{r}, @var{n}) ## @deftypefnx {} {} cylinder (@var{hax}, @dots{}) ## @deftypefnx {} {[@var{x}, @var{y}, @var{z}] =} cylinder (@dots{}) ## Plot a 3-D unit cylinder. ## ## The optional input @var{r} is a vector specifying the radius along the ## unit z-axis. The default is [1 1] indicating radius 1 at @code{Z == 0} ## and at @code{Z == 1}. ## ## The optional input @var{n} determines the number of faces around the ## circumference of the cylinder. The default value is 20. ## ## If the first argument @var{hax} is an axes handle, then plot into this axes, ## rather than the current axes returned by @code{gca}. ## ## If outputs are requested @code{cylinder} returns three matrices in ## @code{meshgrid} format, such that @code{surf (@var{x}, @var{y}, @var{z})} ## generates a unit cylinder. ## ## Example: ## ## @example ## @group ## [x, y, z] = cylinder (10:-1:0, 50); ## surf (x, y, z); ## title ("a cone"); ## @end group ## @end example ## @seealso{ellipsoid, rectangle, sphere} ## @end deftypefn function [x, y, z] = cylinder (varargin) [hax, args, nargs] = __plt_get_axis_arg__ ("cylinder", varargin{:}); if (nargs > 2) print_usage (); elseif (nargs == 0) r = [1, 1]; n = 20; elseif (nargs == 1) r = args{1}; n = 20; else r = args{1}; n = args{2}; endif if (! isvector (r)) error ("cylinder: R must be a scalar or vector"); endif if (isscalar (r)) r .*= [1 1]; # expand single radius specification to required 2-term form endif phi = linspace (0, 2*pi, n+1); idx = 1:length (r); [phi, idx] = meshgrid (phi, idx); zz = (idx - 1) / (length (r) - 1); r = r(idx); [xx, yy] = pol2cart (phi, r); if (nargout > 0) x = xx; y = yy; z = zz; else oldfig = []; if (! isempty (hax)) oldfig = get (0, "currentfigure"); endif unwind_protect hax = newplot (hax); surf (xx, yy, zz); unwind_protect_cleanup if (! isempty (oldfig)) set (0, "currentfigure", oldfig); endif end_unwind_protect endif endfunction %!demo %! clf; %! colormap ("default"); %! [x, y, z] = cylinder (10:-1:0, 50); %! surf (x, y, z); %! title ("cylinder() with linearly shrinking radius produces a cone"); ## Test input validation %!error <Invalid call> cylinder (1,2,3) %!error <R must be a scalar> cylinder ([]) %!error <R must be a scalar or vector> cylinder (ones (2,2))