Mercurial > octave
view scripts/image/prism.m @ 25054:6652d3823428 stable
maint: Update copyright dates in all source files.
author | John W. Eaton <jwe@octave.org> |
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date | Fri, 30 Mar 2018 09:19:05 -0400 |
parents | 2dc04b6e1740 |
children | 00f796120a6d |
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## Copyright (C) 1999-2018 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 ## <https://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {} {@var{map} =} prism () ## @deftypefnx {} {@var{map} =} prism (@var{n}) ## Create color colormap. This colormap cycles through red, orange, yellow, ## green, blue and violet with each index change. ## ## The argument @var{n} must be a scalar. ## If unspecified, the length of the current colormap, or 64, is used. ## @seealso{colormap} ## @end deftypefn ## Author: Kai Habel <kai.habel@gmx.de> function map = prism (n) if (nargin > 1) print_usage (); elseif (nargin == 1) if (! isscalar (n)) error ("prism: N must be a scalar"); endif n = double (n); else hf = get (0, "currentfigure"); if (! isempty (hf)) n = rows (get (hf, "colormap")); else n = 64; endif endif if (n == 1) map = [1 0 0]; elseif (n > 1) C = [1, 0, 0; 1, 1/2, 0; 1, 1, 0; 0, 1, 0; 0, 0, 1; 2/3, 0, 1]; map = C(rem (0:(n-1), 6) + 1, :); else map = zeros (0, 3); endif endfunction %!demo %! ## Show the 'prism' colormap profile and as an image %! cmap = prism (18); # 6 colors, therefore cycle 3 times %! subplot (2, 1, 1); %! rgbplot (cmap, "composite"); %! subplot (2, 1, 2); %! rgbplot (cmap);