Mercurial > octave
view scripts/image/rainbow.m @ 23219:3ac9f9ecfae5 stable
maint: Update copyright dates.
author | John W. Eaton <jwe@octave.org> |
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date | Wed, 22 Feb 2017 12:39:29 -0500 |
parents | bac0d6f07a3e |
children | 092078913d54 |
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## Copyright (C) 1999-2017 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 {} {@var{map} =} rainbow () ## @deftypefnx {} {@var{map} =} rainbow (@var{n}) ## Create color colormap. This colormap ranges from red through orange, ## yellow, green, blue, to violet. ## ## 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> ## this colormap is not part of matlab, it is like the prism ## colormap map but with a continuous map function map = rainbow (n = rows (colormap ())) if (nargin > 1) print_usage (); elseif (! isscalar (n)) error ("rainbow: N must be a scalar"); endif n = double (n); if (n == 1) map = [1, 0, 0]; elseif (n > 1) x = [0:(n-1)]' / (n - 1); 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 = zeros (0, 3); endif endfunction %!demo %! ## Show the 'rainbow' colormap profile and as an image %! cmap = rainbow (256); %! subplot (2, 1, 1); %! rgbplot (cmap, "composite"); %! subplot (2, 1, 2); %! rgbplot (cmap);