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gimp/plug-ins/common/sobel.c

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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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* This plugin by thorsten@arch.usyd.edu.au */
/* Based on S&P's Gauss and Blur filters */
/* updated 11/04/97:
don't use rint;
if gamma-channel: set to white if at least one colour channel is >15 */
/* Update 3/10/97:
#ifdef Max and Min,
save old values
correct 'cancel' behaviour */
#include <stdlib.h>
#include "libgimp/gimp.h"
#include <stdio.h>
#include "gtk/gtk.h"
#include <math.h>
typedef struct
{
gint horizontal;
gint vertical;
gint keep_sign;
} SobelValues;
typedef struct
{
gint run;
} SobelInterface;
/* Declare local functions.
*/
static void query (void);
static void run (char *name,
int nparams,
GParam *param,
int *nreturn_vals,
GParam **return_vals);
static void sobel (GDrawable *drawable,
gint horizontal,
gint vertical,
gint keep_sign);
/*
* Sobel interface
*/
static gint sobel_dialog (void);
/*
* Sobel helper functions
*/
static void sobel_close_callback (GtkWidget *widget,
gpointer data);
static void sobel_ok_callback (GtkWidget *widget,
gpointer data);
static void sobel_toggle_update (GtkWidget *widget,
gpointer data);
static void sobel_prepare_row (GPixelRgn *pixel_rgn,
guchar *data,
int x,
int y,
int w);
GPlugInInfo PLUG_IN_INFO =
{
NULL, /* init_proc */
NULL, /* quit_proc */
query, /* query_proc */
run, /* run_proc */
};
static SobelValues bvals =
{
TRUE, /* horizontal sobel */
TRUE, /* vertical sobel */
TRUE /* keep sign */
};
static SobelInterface bint =
{
FALSE /* run */
};
MAIN ()
static void
query ()
{
static GParamDef args[] =
{
{ PARAM_INT32, "run_mode", "Interactive, non-interactive" },
{ PARAM_IMAGE, "image", "Input image (unused)" },
{ PARAM_DRAWABLE, "drawable", "Input drawable" },
{ PARAM_INT32, "horizontal", "Sobel in horizontal direction" },
{ PARAM_INT32, "vertical", "Sobel in vertical direction" },
{ PARAM_INT32, "keep_sign", "Keep sign of result (one direction only)" },
};
static GParamDef *return_vals = NULL;
static int nargs = sizeof (args) / sizeof (args[0]);
static int nreturn_vals = 0;
gimp_install_procedure ("plug_in_sobel",
"Edge Detection with Sobel Operation",
"This plugin calculates the gradient with a sobel operator. The user can specify which direction to use. When both directions are used, the result is the RMS of the two gradients; if only one direction is used, the result either the absolut value of the gradient, or 127 + gradient (if the 'keep sign' switch is on). This way, information about the direction of the gradient is preserved. Resulting images are not autoscaled.",
"Thorsten Schnier",
"Thorsten Schnier",
"1997",
"<Image>/Filters/Edge-Detect/Sobel",
"RGB*, GRAY*",
PROC_PLUG_IN,
nargs, nreturn_vals,
args, return_vals);
}
static void
run (gchar *name,
gint nparams,
GParam *param,
gint *nreturn_vals,
GParam **return_vals)
{
static GParam values[1];
GDrawable *drawable;
GRunModeType run_mode;
GStatusType status = STATUS_SUCCESS;
run_mode = param[0].data.d_int32;
*nreturn_vals = 1;
*return_vals = values;
values[0].type = PARAM_STATUS;
values[0].data.d_status = status;
switch (run_mode)
{
case RUN_INTERACTIVE:
/* Possibly retrieve data */
gimp_get_data ("plug_in_sobel", &bvals);
/* First acquire information with a dialog */
if (! sobel_dialog ())
return;
break;
case RUN_NONINTERACTIVE:
/* Make sure all the arguments are there! */
if (nparams != 6)
status = STATUS_CALLING_ERROR;
if (status == STATUS_SUCCESS)
{
bvals.horizontal = (param[4].data.d_int32) ? TRUE : FALSE;
bvals.vertical = (param[5].data.d_int32) ? TRUE : FALSE;
bvals.keep_sign = (param[6].data.d_int32) ? TRUE : FALSE;
}
break;
case RUN_WITH_LAST_VALS:
/* Possibly retrieve data */
gimp_get_data ("plug_in_sobel", &bvals);
break;
default:
break;
}
/* 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_color (drawable->id) || gimp_drawable_gray (drawable->id))
{
gimp_tile_cache_ntiles (2 * (drawable->width / gimp_tile_width () + 1));
sobel (drawable, bvals.horizontal, bvals.vertical, bvals.keep_sign);
if (run_mode != RUN_NONINTERACTIVE)
gimp_displays_flush ();
/* Store data */
if (run_mode == RUN_INTERACTIVE)
gimp_set_data ("plug_in_sobel", &bvals, sizeof (bvals));
}
else
{
/* gimp_message ("sobel: cannot operate on indexed color images"); */
status = STATUS_EXECUTION_ERROR;
}
gimp_drawable_detach (drawable);
values[0].data.d_status = status;
}
static gint
sobel_dialog ()
{
GtkWidget *dlg;
GtkWidget *button;
GtkWidget *toggle;
GtkWidget *frame;
GtkWidget *vbox;
GtkWidget *hbox;
gchar **argv;
gint argc;
argc = 1;
argv = g_new (gchar *, 1);
argv[0] = g_strdup ("sobel");
gtk_init (&argc, &argv);
gtk_rc_parse (gimp_gtkrc ());
dlg = gtk_dialog_new ();
gtk_window_set_title (GTK_WINDOW (dlg), "Sobel Edge Detection");
gtk_window_position (GTK_WINDOW (dlg), GTK_WIN_POS_MOUSE);
gtk_signal_connect (GTK_OBJECT (dlg), "destroy",
(GtkSignalFunc) sobel_close_callback,
NULL);
/* Action area */
button = gtk_button_new_with_label ("OK");
GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
gtk_signal_connect (GTK_OBJECT (button), "clicked",
(GtkSignalFunc) sobel_ok_callback,
dlg);
gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dlg)->action_area), button, TRUE, TRUE, 0);
gtk_widget_grab_default (button);
gtk_widget_show (button);
button = gtk_button_new_with_label ("Cancel");
GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
(GtkSignalFunc) gtk_widget_destroy,
GTK_OBJECT (dlg));
gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dlg)->action_area), button, TRUE, TRUE, 0);
gtk_widget_show (button);
/* parameter settings */
frame = gtk_frame_new ("Parameter Settings");
gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_ETCHED_IN);
gtk_container_border_width (GTK_CONTAINER (frame), 10);
gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dlg)->vbox), frame, TRUE, TRUE, 0);
vbox = gtk_vbox_new (FALSE, 5);
gtk_container_border_width (GTK_CONTAINER (vbox), 10);
gtk_container_add (GTK_CONTAINER (frame), vbox);
toggle = gtk_check_button_new_with_label ("Sobel Horizontally");
gtk_box_pack_start (GTK_BOX (vbox), toggle, TRUE, TRUE, 0);
gtk_signal_connect (GTK_OBJECT (toggle), "toggled",
(GtkSignalFunc) sobel_toggle_update,
&bvals.horizontal);
gtk_toggle_button_set_state (GTK_TOGGLE_BUTTON (toggle), bvals.horizontal);
gtk_widget_show (toggle);
toggle = gtk_check_button_new_with_label ("Sobel Vertically");
gtk_box_pack_start (GTK_BOX (vbox), toggle, TRUE, TRUE, 0);
gtk_signal_connect (GTK_OBJECT (toggle), "toggled",
(GtkSignalFunc) sobel_toggle_update,
&bvals.vertical);
gtk_toggle_button_set_state (GTK_TOGGLE_BUTTON (toggle), bvals.vertical);
gtk_widget_show (toggle);
toggle = gtk_check_button_new_with_label ("Keep sign of result (one direction only)");
gtk_box_pack_start (GTK_BOX (vbox), toggle, TRUE, TRUE, 0);
gtk_signal_connect (GTK_OBJECT (toggle), "toggled",
(GtkSignalFunc) sobel_toggle_update,
&bvals.keep_sign);
gtk_toggle_button_set_state (GTK_TOGGLE_BUTTON (toggle), bvals.vertical);
gtk_widget_show (toggle);
hbox = gtk_hbox_new (FALSE, 5);
gtk_box_pack_start (GTK_BOX (vbox), hbox, TRUE, TRUE, 0);
gtk_widget_show (hbox);
gtk_widget_show (vbox);
gtk_widget_show (frame);
gtk_widget_show (dlg);
gtk_main ();
gdk_flush ();
return bint.run;
}
static void
sobel_prepare_row (GPixelRgn *pixel_rgn,
guchar *data,
int x,
int y,
int w)
{
int 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 < pixel_rgn->bpp; b++)
{
data[-pixel_rgn->bpp + b] = data[b];
data[w * pixel_rgn->bpp + b] = data[(w - 1) * pixel_rgn->bpp + b];
}
}
#define SIGN(a) (((a) > 0) ? 1 : -1)
#define RMS(a,b) (sqrt (pow ((a),2) + pow ((b), 2)))
#ifndef MAX
#define MAX(a,b) (((a) > (b)) ? (a) : (b))
#endif
#define ROUND_TO_INT(val) ((val) + 0.5)
static void
sobel (GDrawable *drawable,
gint do_horizontal,
gint do_vertical,
gint keep_sign)
{
GPixelRgn srcPR, destPR;
gint width, height;
gint bytes;
gint gradient, hor_gradient, ver_gradient;
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 alpha;
gint counter;
/* 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->id, &x1, &y1, &x2, &y2);
gimp_progress_init ("Sobel Edge Detect");
/* 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 -> id);
/* allocate row buffers */
prev_row = (guchar *) malloc ((x2 - x1 + 2) * bytes);
cur_row = (guchar *) malloc ((x2 - x1 + 2) * bytes);
next_row = (guchar *) malloc ((x2 - x1 + 2) * bytes);
dest = (guchar *) malloc ((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;
sobel_prepare_row (&srcPR, pr, x1, y1 - 1, (x2 - x1));
sobel_prepare_row (&srcPR, cr, x1, y1, (x2 - x1));
counter =0;
/* loop through the rows, applying the sobel convolution */
for (row = y1; row < y2; row++)
{
/* prepare the next row */
sobel_prepare_row (&srcPR, nr, x1, row + 1, (x2 - x1));
d = dest;
for (col = 0; col < (x2 - x1) * bytes; col++) {
hor_gradient = (do_horizontal ?
((pr[col - bytes] + 2 * pr[col] + pr[col + bytes]) -
(nr[col - bytes] + 2 * nr[col] + nr[col + bytes]))
: 0);
ver_gradient = (do_vertical ?
((pr[col - bytes] + 2 * cr[col - bytes] + nr[col - bytes]) -
(pr[col + bytes] + 2 * cr[col + bytes] + nr[col + bytes]))
: 0);
gradient = (do_vertical && do_horizontal) ?
(ROUND_TO_INT (RMS (hor_gradient, ver_gradient)) / 5.66) /* always >0 */
: (keep_sign ? (127 + (ROUND_TO_INT ((hor_gradient + ver_gradient) / 8.0)))
: (ROUND_TO_INT (abs (hor_gradient + ver_gradient) / 4.0)));
if (alpha && (((col + 1) % bytes) == 0)) { /* the alpha channel */
*d++ = (counter == 0) ? 0 : 255;
counter = 0; }
else {
*d++ = gradient;
if (gradient > 10) 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 % 5) == 0)
gimp_progress_update ((double) row / (double) (y2 - y1));
}
/* update the sobeled region */
gimp_drawable_flush (drawable);
gimp_drawable_merge_shadow (drawable->id, TRUE);
gimp_drawable_update (drawable->id, x1, y1, (x2 - x1), (y2 - y1));
free (prev_row);
free (cur_row);
free (next_row);
free (dest);
}
/* Sobel interface functions */
static void
sobel_close_callback (GtkWidget *widget,
gpointer data)
{
gtk_main_quit ();
}
static void
sobel_ok_callback (GtkWidget *widget,
gpointer data)
{
bint.run = TRUE;
gtk_widget_destroy (GTK_WIDGET (data));
}
static void
sobel_toggle_update (GtkWidget *widget,
gpointer data)
{
int *toggle_val;
toggle_val = (int *) data;
if (GTK_TOGGLE_BUTTON (widget)->active)
*toggle_val = TRUE;
else
*toggle_val = FALSE;
}
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