1997-11-25 06:05:25 +08:00
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/* The GIMP -- an image manipulation program
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* Copyright (C) 1995 Spencer Kimball and Peter Mattis
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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1998-04-13 13:44:11 +08:00
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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1997-11-25 06:05:25 +08:00
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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#include "appenv.h"
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#include "color_transfer.h"
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/* for lightening */
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double highlights_add[256];
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double midtones_add[256];
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double shadows_add[256];
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/* for darkening */
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double highlights_sub[256];
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double midtones_sub[256];
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double shadows_sub[256];
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/* color transfer functions */
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void
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color_transfer_init ()
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{
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int i;
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for (i = 0; i < 256; i++)
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{
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highlights_add[i] = shadows_sub[255 - i] = (1.075 - 1 / ((double) i / 16.0 + 1));
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midtones_add[i] = midtones_sub[i] = 0.667 * (1 - SQR (((double) i - 127.0) / 127.0));
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shadows_add[i] = highlights_sub[i] = 0.667 * (1 - SQR (((double) i - 127.0) / 127.0));
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}
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}
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