GTK+ Forums

virgoptrex@yahoo.com · Familiar Face Joined: 03 Feb 2010 Posts: 21

I am working with GIGE camera in opencv 1.0.0 and GTK+2.0 using gcc. I am interested in streaming live video grabbing individual image frames. I have been able to grab just single frame. My problem is how do I update image on the gtkwidget. or repaint it. I know that my pixbuf is being updated and I cannot put "image" widget inside loop or insertion will fail. How do I tell imy "image" widget to get the new value of pix buffer which is being updated by my capture subroutine? I tried using timer and "expose_event" so far no luck :cry: Any help would be appreciated.

Code: (Plaintext)

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//===================gtk timer and expose event==============================================
static gboolean
on_expose_event(GtkWidget *widget,
GdkEventExpose *event,
gpointer data)
{

capture_image();
//OpenCV clean up
cvReleaseImage(&bayerImage);
cvReleaseImage(&rgbImage);
return FALSE;
}

static gboolean
time_handler(GtkWidget *widget)
{
//capture_image();
gtk_widget_queue_draw(widget);
cvWaitKey(10);
printf("hello!\n");
return TRUE;
}

//===================end of gtk timer and expose event========================================
.
.
.
int main (int argc, char *argv[]) {

//int key = 0;

capture_init();
printf("Camera ID \t\t= %ld\n", myCamera.UID);
gtk_init(&argc, &argv);

capture_image();
image = gtk_image_new_from_pixbuf (pix);

.
.
.
g_signal_connect(G_OBJECT(window), "expose-event",
G_CALLBACK(on_expose_event), NULL);

.
.
.g_timeout_add(10, (GSourceFunc) time_handler, (gpointer) window);
.
.
.
}//end main

Last edited by virgoptrex@yahoo.com on Fri Mar 26, 2010 4:09 pm; edited 2 times in total

virgoptrex@yahoo.com · Familiar Face Joined: 03 Feb 2010 Posts: 21

Solved this after 4 days x 15 hours of struggle as every newbie to GTK would have to go! Try this and simply replace gdk_draw_arc() function!

Code: (C)

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/* Copyright(c) 2010 Virgoptrex. Feel free to use. But leave credits intact :). */
/* My little gift :D to the Open Source Community */
#include <gtk/gtk.h>

gint t=0;

gboolean
expose_event_callback (GtkWidget *widget, GdkEventExpose *event, gpointer data)
{

gtk_widget_queue_draw(GTK_WIDGET(widget));

//g_object_ref_sink (widget->window);

// gdk_drawable_ref (widget->window);

gdk_draw_arc (widget->window,
widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
TRUE,
0, 0, widget->allocation.width, widget->allocation.height,
0, 64 * 18*t);

//gdk_drawable_unref (widget->window);

return TRUE;
}

static gboolean
time_handler(GtkWidget *widget)
{

if (t<20)
{ t++; }
else if (t >=20)
{ t=0; }

printf("hello %d\n",t);
return TRUE;

}

int main( int argc,
char *argv[] )
{
GtkWidget *window;
GtkWidget *aspect_frame;
GtkWidget *drawing_area;
gtk_init (&argc, &argv);

window = gtk_window_new (GTK_WINDOW_TOPLEVEL);

gtk_window_set_title (GTK_WINDOW (window), "Aspect Frame");
g_signal_connect (G_OBJECT (window), "destroy",
G_CALLBACK (gtk_main_quit), NULL);
gtk_container_set_border_width (GTK_CONTAINER (window), 10);

/* Create an aspect_frame and add it to our toplevel window */

aspect_frame = gtk_aspect_frame_new ("2x1", /* label */
0.5, /* center x */
0.5, /* center y */
1.33, /* xsize/ysize = 640/480 = 1.33 */
FALSE /* ignore child's aspect */);

gtk_container_add (GTK_CONTAINER (window), aspect_frame);
gtk_widget_show (aspect_frame);

/* Now add a child widget to the aspect frame */

drawing_area = gtk_drawing_area_new ();

/* Ask for a 200x200 window, but the AspectFrame will give us a 200x100
* window since we are forcing a 2x1 aspect ratio */
gtk_widget_set_size_request (drawing_area, 200, 200);
gtk_container_add (GTK_CONTAINER (aspect_frame), drawing_area);
gtk_widget_show (drawing_area);

g_signal_connect (G_OBJECT (drawing_area), "expose_event",
G_CALLBACK (expose_event_callback), NULL);

g_timeout_add(100, (GSourceFunc) time_handler, (gpointer)drawing_area);

gtk_widget_show (window);
gtk_main ();
return 0;
}

then one may replace the gdk_draw_arc() with some function like...

Last edited by virgoptrex@yahoo.com on Thu Jun 24, 2010 4:08 am; edited 1 time in total

virgoptrex@yahoo.com · Familiar Face Joined: 03 Feb 2010 Posts: 21

Here is the improved code.

Code: (C)

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#include <gtk/gtk.h>

gint t=0;
gint time1;

GtkWidget *window;
GtkWidget *aspect_frame;
GtkWidget *drawing_area;
GtkWidget *vbox1, *toggle1;

gboolean
expose_event_callback (GtkWidget *widget, GdkEventExpose *event, gpointer data)
{

//g_object_ref_sink (widget->window);

// gdk_drawable_ref (widget->window);

gdk_draw_arc (widget->window,
widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
TRUE,
0, 0, widget->allocation.width, widget->allocation.height,
0, 64 * 18*t);

//gdk_drawable_unref (widget->window);
return TRUE;
}

static gboolean
time_handler(GtkWidget *widget)
{

gtk_widget_queue_draw(GTK_WIDGET(widget));

if (t<20)
{ t++; }
else if (t >=20)
{ t=0; }

printf("hello %d\n",t);
return TRUE;

}

void toggle_button_callback (GtkWidget *widget, gpointer data)
{
if (GTK_TOGGLE_BUTTON (widget)->active)
{
g_print("The button %d pressed\n", GPOINTER_TO_INT( g_object_get_data( G_OBJECT( widget),
"id" ) ) );

/* If control reaches here, the toggle button is down */

g_source_remove(time1);

} else {

g_print("The button %d released\n", GPOINTER_TO_INT( g_object_get_data( G_OBJECT( widget),
"id" ) ) );

time1 = g_timeout_add(100, (GSourceFunc) time_handler, (gpointer)drawing_area);

/* If control reaches here, the toggle button is up */

}
}

int main( int argc,
char *argv[] )
{
gtk_init (&argc, &argv);

window = gtk_window_new (GTK_WINDOW_TOPLEVEL);

gtk_window_set_title (GTK_WINDOW (window), "Aspect Frame");
g_signal_connect (G_OBJECT (window), "destroy",
G_CALLBACK (gtk_main_quit), NULL);
gtk_container_set_border_width (GTK_CONTAINER (window), 10);

vbox1 = gtk_vbox_new(TRUE,0);

/* Create an aspect_frame and add it to our toplevel window */

aspect_frame = gtk_aspect_frame_new ("2x1", /* label */
0.5, /* center x */
0.5, /* center y */
2, /* xsize/ysize = 2 */
FALSE /* ignore child's aspect */);

gtk_container_add( GTK_CONTAINER( window ), vbox1 );

toggle1 = gtk_toggle_button_new_with_label ("Hold");
g_signal_connect( toggle1, "toggled", G_CALLBACK( toggle_button_callback ), NULL );
gtk_box_pack_start(GTK_BOX(vbox1), toggle1, TRUE, TRUE,0);

gtk_box_pack_start(GTK_BOX(vbox1), aspect_frame, TRUE, TRUE,0);
gtk_widget_show (aspect_frame);
gtk_widget_show (vbox1);

/* Now add a child widget to the aspect frame */

drawing_area = gtk_drawing_area_new ();

/* Ask for a 200x200 window, but the AspectFrame will give us a 200x100
* window since we are forcing a 2x1 aspect ratio */
gtk_widget_set_size_request (drawing_area, 200, 200);
gtk_container_add (GTK_CONTAINER (aspect_frame), drawing_area);
gtk_widget_show (drawing_area);

g_signal_connect (G_OBJECT (drawing_area), "expose_event",
G_CALLBACK (expose_event_callback), NULL);

time1 = g_timeout_add(100, (GSourceFunc) time_handler, (gpointer)drawing_area);

gtk_widget_show_all (window);
gtk_main ();
return 0;
}