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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 "config.h"
#include <glib-object.h>
#include "base-types.h"
#include "pixel-region.h"
#include "threshold.h"
void
threshold_2 (gpointer data,
PixelRegion *srcPR,
PixelRegion *destPR)
{
threshold (srcPR, destPR, data);
}
void
threshold (PixelRegion *srcPR,
PixelRegion *destPR,
gpointer data)
{
Threshold *tr;
guchar *src, *s;
guchar *dest, *d;
gint has_alpha, alpha;
gint w, h, b;
gint value;
tr = (Threshold *) data;
h = srcPR->h;
src = srcPR->data;
dest = destPR->data;
has_alpha = (srcPR->bytes == 2 || srcPR->bytes == 4);
alpha = has_alpha ? srcPR->bytes - 1 : srcPR->bytes;
while (h--)
{
w = srcPR->w;
s = src;
d = dest;
while (w--)
{
if (tr->color)
{
value = MAX (s[RED_PIX], s[GREEN_PIX]);
value = MAX (value, s[BLUE_PIX]);
value = (value >= tr->low_threshold && value <= tr->high_threshold ) ? 255 : 0;
}
else
value = (s[GRAY_PIX] >= tr->low_threshold && s[GRAY_PIX] <= tr->high_threshold) ? 255 : 0;
for (b = 0; b < alpha; b++)
d[b] = value;
if (has_alpha)
d[alpha] = s[alpha];
s += srcPR->bytes;
d += destPR->bytes;
}
src += srcPR->rowstride;
dest += destPR->rowstride;
}
}
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