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/* The GIMP -- an image manipulation program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* 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.
*/
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "appenv.h"
#include "color_transfer.h"
#define SQR(x) ((x) * (x))
/* for lightening */
double highlights_add[256];
double midtones_add[256];
double shadows_add[256];
/* for darkening */
double highlights_sub[256];
double midtones_sub[256];
double shadows_sub[256];
/* color transfer functions */
void
color_transfer_init ()
{
int i;
for (i = 0; i < 256; i++)
{
highlights_add[i] = shadows_sub[255 - i] = (1.075 - 1 / ((double) i / 16.0 + 1));
midtones_add[i] = midtones_sub[i] = 0.667 * (1 - SQR (((double) i - 127.0) / 127.0));
shadows_add[i] = highlights_sub[i] = 0.667 * (1 - SQR (((double) i - 127.0) / 127.0));
}
}
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