## 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} =} immultiply (@var{a}, @var{b})
## @deftypefnx {Function File} {@var{out} =} immultiply (@var{a}, @var{b}, @var{class})
## Multiply image by another image or constant.
##
## If @var{a} and @var{b} are two images of same size and class, the images are
## multiplied. Alternatively, if @var{b} is a floating-point scalar, @var{a} is
## multiplie by it.
##
## 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}: the values are truncated to the mininum value of the output
## class.
## @seealso{imabsdiff, imadd, imcomplement, imdivide, imlincomb, imsubtract}
## @end deftypefn

function img = immultiply (img, val, out_class = class (img))

  if (nargin < 2 || nargin > 3)
    print_usage;
  endif
  [img, val] = imarithmetics ("immultiply", img, val, out_class, nargin);

  ## have to check how matlab behaves in this situtation. Their documentation
  ## does not say anything but add and subtract silently ignore it and return
  ## double anyway. This may be done in the call to imarithmetics
  if (nargin > 2 && strcmpi (out_class, "logical"))
    warning ("Ignoring request to return logical as output of multiplication.");
  endif

  img = img .* val;

endfunction

%!assert (immultiply (uint8   ([255 50]), uint16  ([300 50])),           uint8  ([255 255]));  # default to first class and truncate
%!assert (immultiply (uint8   ([250 50]), uint16  ([  3  4]), "uint32"), uint32 ([750 200]));  # defining output class works (not in matlab?)
%!assert (immultiply (uint8   ([255 50]),                  4),           uint8  ([255 200]));  # works multiplying by a scalar
%!assert (immultiply (logical ([  1  0]), uint16  ([300 50])),           uint16 ([300   0]));  # output class defaults to whatever input is not logical
%!assert (immultiply (logical ([  1  0]), logical ([  1  1])),           double ([  1   0]));  # tested on matlab for compatibility