update packages

[CreaPhase.git] / octave_packages / m / image / gray2ind.m

diff --git a/octave_packages/m/image/gray2ind.m b/octave_packages/m/image/gray2ind.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{img}, @var{map}] =} gray2ind (@var{I}, @var{n})
+## Convert a gray scale intensity image to an Octave indexed image.
+## The indexed image will consist of @var{n} different intensity values.  If not
+## given @var{n} will default to 64.
+## @end deftypefn
+
+## Author: Tony Richardson <arichard@stark.cc.oh.us>
+## Created: July 1994
+## Adapted-By: jwe
+
+function [X, map] = gray2ind (I, n = 64)
+  ## Check input
+  if (nargin < 1 || nargin > 2)
+    print_usage ();
+  endif
+  C = class(I);
+  if (! ismatrix (I) || ndims (I) != 2)
+    error ("gray2ind: first input argument must be a gray scale image");
+  endif
+  if (! isscalar (n) || n < 0)
+    error ("gray2ind: second input argument must be a positive integer");
+  endif
+  ints = {"uint8", "uint16", "int8", "int16"};
+  floats = {"double", "single"};
+  if (! ismember (C, {ints{:}, floats{:}}))
+    error ("gray2ind: invalid data type '%s'", C);
+  endif
+  if (ismember (C, floats) && (min (I(:)) < 0 || max (I(:)) > 1))
+    error ("gray2ind: floating point images may only contain values between 0 and 1");
+  endif
+
+  ## Convert data
+  map = gray (n);
+  ## If @var{I} is an integer matrix convert it to a double matrix with values in [0, 1]
+  if (ismember (C, ints))
+    low = double (intmin (C));
+    high = double (intmax (C));
+    I = (double (I) - low) / (high - low);
+  endif
+  X = round (I*(n-1)) + 1;
+
+endfunction