gimp/app/desaturate.c

186 lines
4.2 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 <stdlib.h>
#include <string.h>
#include <math.h>
#include "appenv.h"
#include "drawable.h"
#include "desaturate.h"
#include "interface.h"
#include "paint_funcs.h"
#include "gimage.h"
static void desaturate (GimpDrawable *);
static Argument * desaturate_invoker (Argument *);
void
image_desaturate (gimage_ptr)
void *gimage_ptr;
{
GImage *gimage;
GimpDrawable *drawable;
gimage = (GImage *) gimage_ptr;
drawable = gimage_active_drawable (gimage);
if (! drawable_color (drawable))
{
message_box ("Desaturate operates only on RGB color drawables.", NULL, NULL);
return;
}
desaturate (drawable);
}
/* Desaturateer */
static 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));
}
/* The desaturate procedure definition */
ProcArg desaturate_args[] =
{
{ PDB_IMAGE,
"image",
"the image"
},
{ PDB_DRAWABLE,
"drawable",
"the drawable"
}
};
ProcRecord desaturate_proc =
{
"gimp_desaturate",
"Desaturate the contents of the specified drawable",
"This procedure desaturates the contents of the specified drawable. This procedure only works on drawables of type RGB color.",
"Spencer Kimball & Peter Mattis",
"Spencer Kimball & Peter Mattis",
"1995-1996",
PDB_INTERNAL,
/* Input arguments */
2,
desaturate_args,
/* Output arguments */
0,
NULL,
/* Exec method */
{ { desaturate_invoker } },
};
static Argument *
desaturate_invoker (args)
Argument *args;
{
int success = TRUE;
int int_value;
GImage *gimage;
GimpDrawable *drawable;
drawable = NULL;
/* the gimage */
if (success)
{
int_value = args[0].value.pdb_int;
if (! (gimage = gimage_get_ID (int_value)))
success = FALSE;
}
/* the drawable */
if (success)
{
int_value = args[1].value.pdb_int;
drawable = drawable_get_ID (int_value);
if (drawable == NULL || gimage != drawable_gimage (drawable))
success = FALSE;
}
/* check to make sure the drawable is color */
if (success)
success = drawable_color (drawable);
if (success)
desaturate (drawable);
return procedural_db_return_args (&desaturate_proc, success);
}