gimp/app/gimpdrawable-desaturate.c

103 lines
2.6 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 "appenv.h"
#include "drawable.h"
#include "desaturate.h"
#include "paint_funcs.h"
#include "gimage.h"
#include "libgimp/gimpintl.h"
void
image_desaturate (GimpImage *gimage)
{
GimpDrawable *drawable;
drawable = gimage_active_drawable (gimage);
if (! drawable_color (drawable))
{
g_message (_("Desaturate operates only on RGB color drawables."));
return;
}
desaturate (drawable);
}
/* Desaturater */
void
desaturate (GimpDrawable *drawable)
{
PixelRegion srcPR, destPR;
unsigned char *src, *s;
unsigned char *dest, *d;
int h, j;
int lightness, min, max;
int has_alpha;
void *pr;
int x1, y1, x2, y2;
if (!drawable)
return;
has_alpha = drawable_has_alpha (drawable);
drawable_mask_bounds (drawable, &x1, &y1, &x2, &y2);
pixel_region_init (&srcPR, drawable_data (drawable), x1, y1, (x2 - x1), (y2 - y1), FALSE);
pixel_region_init (&destPR, drawable_shadow (drawable), x1, y1, (x2 - x1), (y2 - y1), TRUE);
for (pr = pixel_regions_register (2, &srcPR, &destPR); pr != NULL; pr = pixel_regions_process (pr))
{
src = srcPR.data;
dest = destPR.data;
h = srcPR.h;
while (h--)
{
s = src;
d = dest;
for (j = 0; j < srcPR.w; j++)
{
max = MAXIMUM (s[RED_PIX], s[GREEN_PIX]);
max = MAXIMUM (max, s[BLUE_PIX]);
min = MINIMUM (s[RED_PIX], s[GREEN_PIX]);
min = MINIMUM (min, s[BLUE_PIX]);
lightness = (max + min) / 2;
d[RED_PIX] = lightness;
d[GREEN_PIX] = lightness;
d[BLUE_PIX] = lightness;
if (has_alpha)
d[ALPHA_PIX] = s[ALPHA_PIX];
d += destPR.bytes;
s += srcPR.bytes;
}
src += srcPR.rowstride;
dest += destPR.rowstride;
}
}
drawable_merge_shadow (drawable, TRUE);
drawable_update (drawable, x1, y1, (x2 - x1), (y2 - y1));
}