Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / image-1.0.15 / isgray.m

diff --git a/octave_packages/image-1.0.15/isgray.m b/octave_packages/image-1.0.15/isgray.m
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+## Copyright (C) 2000  Kai Habel
+##
+## This program 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 2 of the License, or
+## (at your option) any later version.
+##
+## This program 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 this program; If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} @var{bool}= isgray (@var{I})
+## Returns true for an gray-scale intensity image. An variable is a gray scale image
+## if it is 2-dimensional matrix, and
+## @itemize @bullet
+## @item is of class double and all values are in the range [0, 1], or
+## @item is of class uint8 or uint16.
+## @end itemize
+## @end deftypefn
+
+## Author:     Kai Habel <kai.habel@gmx.de>
+## Date:       20/03/2000
+
+function bool = isgray (I)
+
+  if (nargin != 1)
+    print_usage ();
+  endif
+
+  bool = false;
+  if (ismatrix(I) && ndims(I) == 2)
+    switch(class(I))
+    case "double"
+      bool = all((I(:) >= 0 & I(:) <= 1) | isnan(I(:)));
+    case {"uint8", "uint16"}
+      bool = true;
+    endswitch
+  endif
+
+endfunction