/usr/share/octave/packages/image-2.4.1/imadd.m is in octave-image 2.4.1-1.
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 65 66 67 68 69 70 71 72 73 | ## 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} =} imadd (@var{a}, @var{b})
## @deftypefnx {Function File} {@var{out} =} imadd (@var{a}, @var{b}, @var{class})
## Add image or constant to an image.
##
## If @var{a} and @var{b} are two images of same size and class, the images are
## added. Alternatively, if @var{b} is a floating-point scalar, its value is added
## to the image @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, it 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 maximum value of the output
## class.
## @seealso{imabsdiff, imcomplement, imdivide, imlincomb, immultiply, imsubtract}
## @end deftypefn
function img = imadd (img, val, out_class = class (img))
if (nargin < 2 || nargin > 3)
print_usage;
endif
[img, val] = imarithmetics ("imadd", img, val, out_class);
## output class is the same as input img, unless img is logical in which case
## it should be double. Tested in matlab by Freysh at ##matlab:
## - if you imadd 2 logical matrix, it's not the union. You actually get values of 2
## - the previous is true even if you specify "logical" as output class. It does
## not honors the request, output will be double class anyway, not even a
## warning will be issued (but we in octave are nicer and will)
## - you can specify smaller integer types for output than input and values
## are truncated. Input uint16 and request uint8, it will be respected
## this is matlab imcompatible on purpose. We are compatible and return double
## anyway, even if both input are logical (and wether this is correct is
## already debatable), but if the user forcedly requests output class to be
## logical, then he must be expecting it (matlab returns double anyway and
## ignores request).
if (nargin > 2 && strcmpi (out_class, "logical"))
img = img | val;
else
img = img + val;
endif
endfunction
%!assert (imadd (uint8 ([23 250]), uint8 ([23 250])), uint8 ([46 255])); # default to first class and truncate
%!assert (imadd (uint8 ([23 250]), 10), uint8 ([33 255])); # works adding a scalar
%!assert (imadd (uint8 ([23 250]), uint8 ([23 250]), "uint16"), uint16 ([46 500])); # defining output class works
%!assert (imadd (logical ([ 1 0]), logical ([ 1 1])), double ([ 2 1])); # return double for two logical images
%!assert (imadd (logical ([ 1 0]), logical ([ 1 1]), "logical"), logical ([ 1 1])); # this is matlab incompatible on purpose
%!fail ("imadd (uint8 ([23 250]), uint16 ([23 250]))"); # input need to have same class
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