Mercurial > octave-nkf
view scripts/image/hot.m @ 16033:23a7661e529a ss-3-7-2
snapshot version 3.7.2
* configure.ac (AC_INIT): Set version to 3.7.2.
(OCTAVE_RELEASE_DATE): Set to 2013-02-09.
(OCTAVE_COPYRIGHT): Update year.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Sun, 10 Feb 2013 00:59:19 -0500 |
parents | 1a800034d443 |
children | 6964e6b92fc1 |
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## Copyright (C) 1999-2012 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 {Function File} {@var{map} =} hot () ## @deftypefnx {Function File} {@var{map} =} hot (@var{n}) ## Create color colormap. This colormap ranges from black through dark red, ## red, orange, yellow, to white. ## 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> ## PKG_ADD: colormap ("register", "hot"); ## PKG_DEL: colormap ("unregister", "hot"); function map = hot (n) if (nargin == 0) n = rows (colormap); elseif (nargin == 1) if (! isscalar (n)) error ("hot: N must be a scalar"); endif else print_usage (); endif if (n == 1) map = [1, 1, 1]; elseif (n > 1) x = linspace (0, 1, n)'; r = (x < 2/5) .* (5/2 * x) ... + (x >= 2/5); g = (x >= 2/5 & x < 4/5) .* (5/2 * x - 1) ... + (x >= 4/5); b = (x >= 4/5) .* (5 * x - 4); map = [r, g, b]; else map = zeros (0, 3); endif endfunction %!demo %! ## Show the 'hot' colormap as an image %! image (1:64, linspace (0, 1, 64), repmat ((1:64)', 1, 64)); %! axis ([1, 64, 0, 1], "ticy", "xy"); %! colormap (hot (64));