1## Copyright (C) 2011 Carnë Draug <carandraug+dev@gmail.com> 2## 3## This program is free software; you can redistribute it and/or modify it under 4## the terms of the GNU General Public License as published by the Free Software 5## Foundation; either version 3 of the License, or (at your option) any later 6## version. 7## 8## This program is distributed in the hope that it will be useful, but WITHOUT 9## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 11## details. 12## 13## You should have received a copy of the GNU General Public License along with 14## this program; if not, see <http://www.gnu.org/licenses/>. 15 16## -*- texinfo -*- 17## @deftypefn {Function File} {@var{out} =} immultiply (@var{a}, @var{b}) 18## @deftypefnx {Function File} {@var{out} =} immultiply (@var{a}, @var{b}, @var{class}) 19## Multiply image by another image or constant. 20## 21## If @var{a} and @var{b} are two images of same size and class, the images are 22## multiplied. Alternatively, if @var{b} is a floating-point scalar, @var{a} is 23## multiplied by it. 24## 25## The class of @var{out} will be the same as @var{a} unless @var{a} is logical 26## in which case @var{out} will be double. Alternatively, it can be 27## specified with @var{class}. 28## 29## @emph{Note}: the values are truncated to the mininum value of the output 30## class. 31## @seealso{imabsdiff, imadd, imcomplement, imdivide, imlincomb, imsubtract} 32## @end deftypefn 33 34function img = immultiply (img, val, out_class = class (img)) 35 36 if (nargin < 2 || nargin > 3) 37 print_usage; 38 endif 39 [img, val] = imarithmetics ("immultiply", img, val, out_class, nargin); 40 41 ## have to check how matlab behaves in this situation. Their documentation 42 ## does not say anything but add and subtract silently ignore it and return 43 ## double anyway. This may be done in the call to imarithmetics 44 if (nargin > 2 && strcmpi (out_class, "logical")) 45 warning ("Ignoring request to return logical as output of multiplication."); 46 endif 47 48 img = img .* val; 49 50endfunction 51 52%!assert (immultiply (uint8 ([255 50]), uint16 ([300 50])), uint8 ([255 255])); # default to first class and truncate 53%!assert (immultiply (uint8 ([250 50]), uint16 ([ 3 4]), "uint32"), uint32 ([750 200])); # defining output class works (not in matlab?) 54%!assert (immultiply (uint8 ([255 50]), 4), uint8 ([255 200])); # works multiplying by a scalar 55%!assert (immultiply (logical ([ 1 0]), uint16 ([300 50])), uint16 ([300 0])); # output class defaults to whatever input is not logical 56%!assert (immultiply (logical ([ 1 0]), logical ([ 1 1])), double ([ 1 0])); # tested on matlab for compatibility 57