gimp/app/color_transfer.c

59 lines
1.5 KiB
C

/* 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 "config.h"
#include <glib.h>
#include "libgimpmath/gimpmath.h"
#include "apptypes.h"
#include "color_transfer.h"
/* for lightening */
gdouble highlights_add[256];
gdouble midtones_add[256];
gdouble shadows_add[256];
/* for darkening */
gdouble highlights_sub[256];
gdouble midtones_sub[256];
gdouble shadows_sub[256];
/* color transfer functions */
void
color_transfer_init (void)
{
gint i;
for (i = 0; i < 256; i++)
{
highlights_add[i] =
shadows_sub[255 - i] = (1.075 - 1 / ((gdouble) i / 16.0 + 1));
midtones_add[i] =
midtones_sub[i] = 0.667 * (1 - SQR (((gdouble) i - 127.0) / 127.0));
shadows_add[i] =
highlights_sub[i] = 0.667 * (1 - SQR (((gdouble) i - 127.0) / 127.0));
}
}