Mercurial > octave-nkf
view scripts/image/rainbow.m @ 6791:be31a048c449
[project @ 2007-07-24 19:04:51 by dbateman]
author | dbateman |
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date | Tue, 24 Jul 2007 19:04:51 +0000 |
parents | c81a0f3f5a82 |
children | 93c65f2a5668 |
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## Copyright (C) 1999,2000 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 2, 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, write to the Free ## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA ## 02110-1301, USA. ## -*- texinfo -*- ## @deftypefn {Function File} {} rainbow (@var{n}) ## Create color colormap. This colormap is red through orange, yellow, green, ## blue to violet. The argument @var{n} should be a scalar. If it ## is omitted, the length of the current colormap or 64 is assumed. ## @seealso{colormap} ## @end deftypefn ## Author: Kai Habel <kai.habel@gmx.de> function map = rainbow (number) ## this colormap is not part of matlab, it is like the prism ## colormap map but with a continuous map if (nargin == 0) number = rows (colormap); elseif (nargin == 1) if (! isscalar (number)) error ("rainbow: argument must be a scalar"); endif else print_usage (); endif if (number == 1) map = [1, 0, 0]; elseif (number > 1) x = linspace (0, 1, number)'; r = (x < 2/5) + (x >= 2/5 & x < 3/5) .* (-5 * x + 3)\ + (x >= 4/5) .* (10/3 * x - 8/3); g = (x < 2/5) .* (5/2 * x) + (x >= 2/5 & x < 3/5)\ + (x >= 3/5 & x < 4/5) .* (-5 * x + 4); b = (x >= 3/5 & x < 4/5) .* (5 * x - 3) + (x >= 4/5); map = [r, g, b]; else map = []; endif endfunction