1 ## Copyright (C) 1994-2012 John W. Eaton
3 ## This file is part of Octave.
5 ## Octave is free software; you can redistribute it and/or modify it
6 ## under the terms of the GNU General Public License as published by
7 ## the Free Software Foundation; either version 3 of the License, or (at
8 ## your option) any later version.
10 ## Octave is distributed in the hope that it will be useful, but
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 ## General Public License for more details.
15 ## You should have received a copy of the GNU General Public License
16 ## along with Octave; see the file COPYING. If not, see
17 ## <http://www.gnu.org/licenses/>.
20 ## @deftypefn {Function File} {@var{rgb} =} ind2rgb (@var{x}, @var{map})
21 ## @deftypefnx {Function File} {[@var{R}, @var{R}, @var{R}] =} ind2rgb (@var{x}, @var{map})
22 ## Convert an indexed image to red, green, and blue color components.
23 ## If the colormap doesn't contain enough colors, pad it with the
24 ## last color in the map.
25 ## If @var{map} is omitted, the current colormap is used for the conversion.
26 ## @seealso{rgb2ind, image, imshow, ind2gray, gray2ind}
29 ## Author: Tony Richardson <arichard@stark.cc.oh.us>
33 function [R, G, B] = ind2rgb (x, map)
35 ## Do we have the right number of inputs?
36 if (nargin < 1 || nargin > 2)
42 ## Check if X is an indexed image.
43 if (ndims (x) != 2 || any (x(:) != fix (x(:))) || min (x(:)) < 1)
44 error ("ind2rgb: X must be an indexed image");
47 ## Check the color map.
48 if (ndims (map) != 2 || columns (map) != 3)
49 error ("ind2rgb: MAP must be a valid colormap");
52 ## Do we have enough colors in the color map?
56 ## Pad with the last color in the map.
57 pad = repmat (map(end,:), maxidx-rm, 1);
58 map(end+1:maxidx, :) = pad;
63 R = reshape (map (x(:), 1), hi, wi);
64 G = reshape (map (x(:), 2), hi, wi);
65 B = reshape (map (x(:), 3), hi, wi);
67 ## Use 3D array if only one output is requested.