/usr/share/octave/packages/image-2.2.2/imabsdiff.m is in octave-image 2.2.2-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 | ## Copyright (C) 2011 Carnë Draug <carandraug+dev@gmail.com>
##
## 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 3 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{out} =} imabsdiff (@var{a}, @var{b})
## @deftypefnx {Function File} {@var{out} =} imabsdiff (@var{a}, @var{b}, @var{class})
## Return absolute difference of image or constant to an image.
##
## If @var{a} and @var{b} are two images of same size and class, returns the absolute
## difference between @var{b} and @var{a}.
##
## The class of @var{out} will be the same as @var{a} unless @var{a} is logical
## in which case @var{out} will be double. Alternatively, the class can be
## specified with @var{class}.
##
## @emph{Note 1}: you can force output class to be logical by specifying
## @var{class}. This is incompatible with @sc{matlab} which will @emph{not} honour
## request to return a logical matrix.
##
## @emph{Note 2}: the values are truncated to the mininum value of the output
## class.
## @seealso{imadd, imcomplement, imdivide, imlincomb, immultiply, imsubtract}
## @end deftypefn
function img = imabsdiff (img, val, out_class = class (img))
if (nargin < 2 || nargin > 3)
print_usage;
endif
## we want to make subtraction as double so this is it
[img, val] = imarithmetics ("imabsdiff", img, val, "double");
converter = str2func (tolower (out_class));
if (nargin < 3 && strcmp (out_class, "logical"))
## it is using logical as default. Use double instead. We only have this
## problem on this function because we are are not actually giving out_class
## to imarithmetics
converter = @double;
else
converter = str2func (tolower (out_class));
endif
img = converter (abs (img - val));
endfunction
%!assert (imabsdiff (uint8 ([23 250]), uint8 ([26 50])), uint8 ([ 3 200])); # default to first class and abs works
%!assert (imabsdiff (uint8 ([23 250]), uint8 ([24 50]), "uint16"), uint16 ([ 1 200])); # defining output class works (not in matlab)
%!assert (imabsdiff (uint8 ([23 250]), uint8 ([24 255]), "int8"), int8 ([ 1 5])); # signed integers kinda work (not in matlab)
%!assert (imabsdiff (logical ([ 1 0]), logical ([ 1 1])), double ([ 0 1])); # return double for two logical images
%!fail ("imabsdiff (uint8 ([23 250]), 30"); # fails subtracting a scalar
%!fail ("imabsdiff (uint8 ([23 250]), uint16 ([23 250]))"); # input need to have same class
|