scale.h

/*
   normalmap GIMP plugin

   Copyright (C) 2002-2012 Shawn Kirst <skirst@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 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; see the file COPYING.  If not, write to
   the Free Software Foundation, 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301 USA.
*/

#ifndef __SCALE_H
#define __SCALE_H

void scale_pixels(unsigned char *dst, int dw, int dh,
                  unsigned char *src, int sw, int sh,
                  int bpp);

static inline int icerp(int a, int b, int c, int d, int x)
{
   int p = (d - c) - (a - b);
   int q = (a - b) - p;
   int r = c - a;
   return((x * (x * (x * p + (q << 7)) + (r << 14)) + (b << 21)) >> 21);
}

#endif