update packages

[CreaPhase.git] / octave_packages / m / image / ind2rgb.m

diff --git a/octave_packages/m/image/ind2rgb.m b/octave_packages/m/image/ind2rgb.m
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+## Copyright (C) 1994-2012 John W. Eaton
+##
+## 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{rgb} =} ind2rgb (@var{x}, @var{map})
+## @deftypefnx {Function File} {[@var{R}, @var{R}, @var{R}] =} ind2rgb (@var{x}, @var{map})
+## Convert an indexed image to red, green, and blue color components.
+## If the colormap doesn't contain enough colors, pad it with the
+## last color in the map.
+## If @var{map} is omitted, the current colormap is used for the conversion.
+## @seealso{rgb2ind, image, imshow, ind2gray, gray2ind}
+## @end deftypefn
+
+## Author: Tony Richardson <arichard@stark.cc.oh.us>
+## Created: July 1994
+## Adapted-By: jwe
+
+function [R, G, B] = ind2rgb (x, map)
+
+  ## Do we have the right number of inputs?
+  if (nargin < 1 || nargin > 2)
+    print_usage ();
+  elseif (nargin == 1)
+    map = colormap ();
+  endif
+
+  ## Check if X is an indexed image.
+  if (ndims (x) != 2 || any (x(:) != fix (x(:))) || min (x(:)) < 1)
+    error ("ind2rgb: X must be an indexed image");
+  endif
+
+  ## Check the color map.
+  if (ndims (map) != 2 || columns (map) != 3)
+    error ("ind2rgb: MAP must be a valid colormap");
+  endif
+
+  ## Do we have enough colors in the color map?
+  maxidx = max (x(:));
+  rm = rows (map);
+  if (rm < maxidx)
+    ## Pad with the last color in the map.
+    pad = repmat (map(end,:), maxidx-rm, 1);
+    map(end+1:maxidx, :) = pad;
+  endif
+
+  ## Compute result
+  [hi, wi] = size (x);
+  R = reshape (map (x(:), 1), hi, wi);
+  G = reshape (map (x(:), 2), hi, wi);
+  B = reshape (map (x(:), 3), hi, wi);
+
+  ## Use 3D array if only one output is requested.
+  if (nargout <= 1)
+    R(:,:,3) = B;
+    R(:,:,2) = G;
+  endif
+endfunction