////////////////////////////////////////////////////////////
// SIVP - Scilab Image and Video Processing toolbox
// Copyright (C) 2006  Shiqi Yu
//
// 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, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
////////////////////////////////////////////////////////////

function [im2] = im2int16(im)
  imtype = typeof(im(1));
	 
  select imtype
   case 'boolean' then
    im2 = int16(int32(im)*(2^16-1) - 2^15);
   case 'uint8' then
    im2 = int16(double(im)*(2^16-1)/(2^8-1)-2^15);
   case 'int8' then
    im2 = int16((double(im)+(128))*(2^16-1)/(2^8-1)-2^15);
   case 'uint16' then
    im2 = int16(int32(im) - 2^15);
   case 'int16' then
    im2 = im;
   case 'int32' then
    im2 = int16( round((double(im)+2^31)*(2^16-1)/(2^32-1) - 2^15));
   case 'constant' then
    im(im>1.0) = 1.0;
    im(im<0.0) = 0.0;
    im2 = int16(round(im * (2^16-1) - 2^15));
   else
    error("Data type " + imtype + " is not supported.");
   end
endfunction