Mercurial > hg > octave-nkf
annotate scripts/plot/cylinder.m @ 9245:16f53d29049f
update copyright notices
| author | John W. Eaton <jwe@octave.org> |
|---|---|
| date | Fri, 22 May 2009 10:46:00 -0400 |
| parents | 1bf0ce0930be |
| children | 95c3e38098bf |
| rev | line source |
|---|---|
| 9245 | 1 ## Copyright (C) 2007, 2009 Michael Goffioul and Kai Habel |
| 7181 | 2 ## |
| 3 ## This file is part of Octave. | |
| 4 ## | |
| 5 ## Octave is free software; you can redistribute it and/or modify it | |
| 6 ## under the terms of the GNU General Public License as published by | |
| 7 ## the Free Software Foundation; either version 3 of the License, or (at | |
| 8 ## your option) any later version. | |
| 9 ## | |
| 10 ## Octave is distributed in the hope that it will be useful, but | |
| 11 ## WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 ## General Public License for more details. | |
| 14 ## | |
| 15 ## You should have received a copy of the GNU General Public License | |
| 16 ## along with Octave; see the file COPYING. If not, see | |
| 17 ## <http://www.gnu.org/licenses/>. | |
| 18 | |
| 19 ## -*- texinfo -*- | |
| 20 ## @deftypefn {Function File} {} cylinder | |
| 21 ## @deftypefnx {Function File} {} cylinder (@var{r}) | |
| 22 ## @deftypefnx {Function File} {} cylinder (@var{r}, @var{n}) | |
| 23 ## @deftypefnx {Function File} {[@var{x}, @var{y}, @var{z}] =} cylinder (@dots{}) | |
| 24 ## @deftypefnx {Function File} {} cylinder (@var{ax}, @dots{}) | |
| 25 ## Generates three matrices in @code{meshgrid} format, such that | |
| 26 ## @code{surf (@var{x}, @var{y}, @var{z})} generates a unit cylinder. | |
| 27 ## The matrices are of size @code{@var{n}+1}-by-@code{@var{n}+1}. | |
| 28 ## @var{r} is a vector containing the radius along the z-axis. | |
| 29 ## If @var{n} or @var{r} are omitted then default values of 20 or [1 1] | |
| 30 ## are assumed. | |
| 31 ## | |
| 32 ## Called with no return arguments, @code{cylinder} calls directly | |
|
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33 ## @code{surf (@var{x}, @var{y}, @var{z})}. If an axes handle @var{ax} |
| 7182 | 34 ## is passed as the first argument, the surface is plotted to this set |
| 35 ## of axes. | |
| 7181 | 36 ## |
| 37 ## Examples: | |
| 38 ## @example | |
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39 ## @group |
| 7182 | 40 ## disp ("plotting a cone") |
| 41 ## [x, y, z] = cylinder (10:-1:0,50); | |
| 42 ## surf (x, y, z); | |
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43 ## @end group |
| 7181 | 44 ## @end example |
| 45 ## @seealso{sphere} | |
| 46 ## @end deftypefn | |
| 47 | |
| 7182 | 48 function [xx, yy, zz] = cylinder (varargin) |
| 7181 | 49 |
| 7215 | 50 [ax, args, nargs] = __plt_get_axis_arg__ ((nargout > 0), "cylinder", |
| 51 varargin{:}); | |
| 7181 | 52 |
| 53 if (nargs == 0) | |
| 54 n = 20; | |
| 7182 | 55 r = [1, 1]; |
| 7181 | 56 elseif (nargs == 1) |
| 57 n = 20; | |
| 58 r = args{1}; | |
| 59 elseif (nargs == 2) | |
| 60 r = args{1}; | |
| 61 n = args{2}; | |
| 62 else | |
| 7182 | 63 print_usage (); |
| 7181 | 64 endif |
| 65 | |
| 7182 | 66 if (length (r) < 2) |
| 67 error ("cylinder: length(r) must be larger than 2") | |
| 7181 | 68 endif |
| 69 | |
| 7182 | 70 phi = linspace (0, 2*pi, n+1); |
| 7181 | 71 idx = 1:length(r); |
| 72 [phi, idx] = meshgrid(phi, idx); | |
| 73 z = (idx - 1) / (length(r) - 1); | |
| 74 r = r(idx); | |
| 7182 | 75 [x, y] = pol2cart (phi, r); |
| 7181 | 76 |
| 77 if (nargout > 0) | |
| 78 xx = x; | |
| 79 yy = y; | |
| 80 zz = z; | |
| 81 else | |
| 7215 | 82 surf (ax, x, y, z); |
| 7181 | 83 endif |
| 84 | |
| 85 endfunction | |
| 7245 | 86 |
| 87 %!demo | |
| 88 %! disp ("plotting a cone") | |
| 89 %! [x, y, z] = cylinder (10:-1:0,50); | |
| 90 %! surf (x, y, z); |