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gimp/plug-ins/common/edge-laplace.c

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/* GIMP - The GNU 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.
*/
/* This plugin by thorsten@arch.usyd.edu.au.
* Based on S&P's Gauss and Laplace filters.
*/
#include "config.h"
#include <stdlib.h>
#include <libgimp/gimp.h>
#include "libgimp/stdplugins-intl.h"
#define PLUG_IN_PROC "plug-in-laplace"
#define PLUG_IN_BINARY "edge-laplace"
/* Declare local functions.
*/
static void query (void);
static void run (const gchar *name,
gint nparams,
const GimpParam *param,
gint *nreturn_vals,
GimpParam **return_vals);
static void laplace (GimpDrawable *drawable);
static void laplace_prepare_row (GimpPixelRgn *pixel_rgn,
guchar *data,
gint x,
gint y,
gint w);
const GimpPlugInInfo PLUG_IN_INFO =
{
NULL, /* init_proc */
NULL, /* quit_proc */
query, /* query_proc */
run, /* run_proc */
};
MAIN ()
static void
query (void)
{
static const GimpParamDef args[] =
{
{ GIMP_PDB_INT32, "run-mode", "Interactive, non-interactive" },
{ GIMP_PDB_IMAGE, "image", "Input image (unused)" },
{ GIMP_PDB_DRAWABLE, "drawable", "Input drawable" }
};
gimp_install_procedure (PLUG_IN_PROC,
N_("High-resolution edge detection"),
"This plugin creates one-pixel wide edges from the "
"image, with the value proportional to the gradient. "
"It uses the Laplace operator (a 3x3 kernel with -8 "
"in the middle). The image has to be laplacered to "
"get useful results, a gauss_iir with 1.5 - 5.0 "
"depending on the noise in the image is best.",
"Thorsten Schnier",
"Thorsten Schnier",
"1997",
N_("_Laplace"),
"RGB*, GRAY*",
GIMP_PLUGIN,
G_N_ELEMENTS (args), 0,
args, NULL);
gimp_plugin_menu_register (PLUG_IN_PROC, "<Image>/Filters/Edge-Detect");
}
static void
run (const gchar *name,
gint nparams,
const GimpParam *param,
gint *nreturn_vals,
GimpParam **return_vals)
{
static GimpParam values[1];
GimpDrawable *drawable;
GimpRunMode run_mode;
GimpPDBStatusType status = GIMP_PDB_SUCCESS;
run_mode = param[0].data.d_int32;
INIT_I18N();
/* Get the specified drawable */
drawable = gimp_drawable_get (param[2].data.d_drawable);
/* Make sure that the drawable is gray or RGB color */
if (gimp_drawable_is_rgb (drawable->drawable_id) ||
gimp_drawable_is_gray (drawable->drawable_id))
{
gimp_tile_cache_ntiles (2 * (drawable->width / gimp_tile_width () + 1));
laplace (drawable);
if (run_mode != GIMP_RUN_NONINTERACTIVE)
gimp_displays_flush ();
}
else
{
/* gimp_message ("laplace: cannot operate on indexed color images"); */
status = GIMP_PDB_EXECUTION_ERROR;
}
*nreturn_vals = 1;
*return_vals = values;
values[0].type = GIMP_PDB_STATUS;
values[0].data.d_status = status;
gimp_drawable_detach (drawable);
}
static void
laplace_prepare_row (GimpPixelRgn *pixel_rgn,
guchar *data,
gint x,
gint y,
gint w)
{
gint bpp = pixel_rgn->bpp;
gint b;
if (y < 0)
{
gimp_pixel_rgn_get_row (pixel_rgn, data, x, (y + 1), w);
}
else if (y == pixel_rgn->h)
{
gimp_pixel_rgn_get_row (pixel_rgn, data, x, (y - 1), w);
}
else
{
gimp_pixel_rgn_get_row (pixel_rgn, data, x, y, w);
}
/* Fill in edge pixels */
for (b = 0; b < bpp; b++)
{
data[b - bpp] = data[b];
data[w * bpp + b] = data[(w - 1) * bpp + b];
}
}
#define BLACK_REGION(val) ((val) > 128)
#define WHITE_REGION(val) ((val) <= 128)
static void
minmax (gint x1,
gint x2,
gint x3,
gint x4,
gint x5,
gint *min_result,
gint *max_result)
{
gint min1, min2, max1, max2;
if (x1 > x2)
{
max1 = x1;
min1 = x2;
}
else
{
max1 = x2;
min1 = x1;
}
if (x3 > x4)
{
max2 = x3;
min2 = x4;
}
else
{
max2 = x4;
min2 = x3;
}
if (min1 < min2)
*min_result = MIN (min1, x5);
else
*min_result = MIN (min2, x5);
if (max1 > max2)
*max_result = MAX (max1, x5);
else
*max_result = MAX (max2, x5);
}
static void
laplace (GimpDrawable *drawable)
{
GimpPixelRgn srcPR, destPR;
gint width, height;
gint bytes;
gint current;
gint gradient;
gint alpha;
gint counter;
guchar *dest, *d;
guchar *prev_row, *pr;
guchar *cur_row, *cr;
guchar *next_row, *nr;
guchar *tmp;
gint row, col;
gint x1, y1, x2, y2;
gint minval, maxval;
/* Get the input area. This is the bounding box of the selection in
* the image (or the entire image if there is no selection). Only
* operating on the input area is simply an optimization. It doesn't
* need to be done for correct operation. (It simply makes it go
* faster, since fewer pixels need to be operated on).
*/
gimp_drawable_mask_bounds (drawable->drawable_id, &x1, &y1, &x2, &y2);
gimp_progress_init (_("Laplace"));
/* Get the size of the input image. (This will/must be the same
* as the size of the output image.
*/
width = drawable->width;
height = drawable->height;
bytes = drawable->bpp;
alpha = gimp_drawable_has_alpha (drawable->drawable_id);
/* allocate row buffers */
prev_row = g_new (guchar, (x2 - x1 + 2) * bytes);
cur_row = g_new (guchar, (x2 - x1 + 2) * bytes);
next_row = g_new (guchar, (x2 - x1 + 2) * bytes);
dest = g_new (guchar, (x2 - x1) * bytes);
/* initialize the pixel regions */
gimp_pixel_rgn_init (&srcPR, drawable, 0, 0, width, height, FALSE, FALSE);
gimp_pixel_rgn_init (&destPR, drawable, 0, 0, width, height, TRUE, TRUE);
pr = prev_row + bytes;
cr = cur_row + bytes;
nr = next_row + bytes;
laplace_prepare_row (&srcPR, pr, x1, y1 - 1, (x2 - x1));
laplace_prepare_row (&srcPR, cr, x1, y1, (x2 - x1));
/* loop through the rows, applying the laplace convolution */
for (row = y1; row < y2; row++)
{
/* prepare the next row */
laplace_prepare_row (&srcPR, nr, x1, row + 1, (x2 - x1));
d = dest;
for (col = 0; col < (x2 - x1) * bytes; col++)
if (alpha && (((col + 1) % bytes) == 0)) /* the alpha channel */
{
*d++ = cr[col];
}
else
{
minmax (pr[col], cr[col - bytes], cr[col], cr[col + bytes],
nr[col], &minval, &maxval); /* four-neighbourhood */
gradient = (0.5 * MAX ((maxval - cr [col]), (cr[col]- minval)));
*d++ = (((pr[col - bytes] + pr[col] + pr[col + bytes] +
cr[col - bytes] - (8 * cr[col]) + cr[col + bytes] +
nr[col - bytes] + nr[col] + nr[col + bytes]) > 0) ?
gradient : (128 + gradient));
}
/* store the dest */
gimp_pixel_rgn_set_row (&destPR, dest, x1, row, (x2 - x1));
/* shuffle the row pointers */
tmp = pr;
pr = cr;
cr = nr;
nr = tmp;
if ((row % 20) == 0)
gimp_progress_update ((gdouble) row / (gdouble) (y2 - y1));
}
/* now clean up: leave only edges, but keep gradient value */
gimp_pixel_rgn_init (&srcPR, drawable, 0, 0, width, height, FALSE, TRUE);
pr = prev_row + bytes;
cr = cur_row + bytes;
nr = next_row + bytes;
laplace_prepare_row (&srcPR, pr, x1, y1 - 1, (x2 - x1));
laplace_prepare_row (&srcPR, cr, x1, y1, (x2 - x1));
gimp_progress_init (_("Cleanup"));
counter =0;
/* loop through the rows, applying the laplace convolution */
for (row = y1; row < y2; row++)
{
/* prepare the next row */
laplace_prepare_row (&srcPR, nr, x1, row + 1, (x2 - x1));
d = dest;
for (col = 0; col < (x2 - x1) * bytes; col++)
{
current = cr[col];
current = ((WHITE_REGION (current) &&
(BLACK_REGION (pr[col - bytes]) ||
BLACK_REGION (pr[col]) ||
BLACK_REGION (pr[col + bytes]) ||
BLACK_REGION (cr[col - bytes]) ||
BLACK_REGION (cr[col + bytes]) ||
BLACK_REGION (nr[col - bytes]) ||
BLACK_REGION (nr[col]) ||
BLACK_REGION (nr[col + bytes]))) ?
((current >= 128) ? (current - 128) : current) : 0);
if (alpha && (((col + 1) % bytes) == 0)) /* the alpha channel */
{
*d++ = (counter == 0) ? 0 : 255;
counter = 0;
}
else
{
*d++ = current;
if (current > 15)
counter ++;
}
}
/* store the dest */
gimp_pixel_rgn_set_row (&destPR, dest, x1, row, (x2 - x1));
/* shuffle the row pointers */
tmp = pr;
pr = cr;
cr = nr;
nr = tmp;
if ((row % 20) == 0)
gimp_progress_update ((gdouble) row / (gdouble) (y2 - y1));
}
/* update the laplaced region */
gimp_drawable_flush (drawable);
gimp_drawable_merge_shadow (drawable->drawable_id, TRUE);
gimp_drawable_update (drawable->drawable_id, x1, y1, (x2 - x1), (y2 - y1));
g_free (prev_row);
g_free (cur_row);
g_free (next_row);
g_free (dest);
}
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