Mercurial > octave
view scripts/image/hsv.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 {} {} hsv (@var{n}) ## Create color colormap. This colormap begins with red, changes through ## yellow, green, cyan, blue, and magenta, before returning to red. ## ## It is useful for displaying periodic functions. The map is obtained by ## linearly varying the hue through all possible values while keeping constant ## maximum saturation and value. The equivalent code is ## @code{hsv2rgb ([(0:N-1)'/N, ones(N,2)])}. ## ## 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 = hsv (n = rows (colormap ())) if (nargin > 1) print_usage (); elseif (! isscalar (n)) error ("hsv: N must be a scalar"); endif n = double (n); if (n == 1) map = [1, 0, 0]; elseif (n > 1) hue = [0:n-1]' / n; map = hsv2rgb ([hue, ones(n,1), ones(n,1)]); else map = zeros (0, 3); endif endfunction ## A better demo of this colormap would be to plot the hsv values. %!demo %! ## Show the 'hsv' colormap profile and as an image %! cmap = hsv (256); %! subplot (2, 1, 1); %! rgbplot (cmap, "composite"); %! subplot (2, 1, 2); %! rgbplot (cmap);