GTK+ Forums

roscarby · Familiar Face Joined: 27 Jun 2007 Posts: 5

I am totally new to Gtk+ and in order to get a first overview of these libraries I am trying to understand some basic examples taken by the net. I have a problem about the following example code:

Code: (Plaintext)

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/* compile using:
cc -Wall -g `pkg-config --cflags --libs gtk+-2.0` -o example main.c
*/

#include <gtk/gtk.h>

void on_window_map (GtkWidget*, gpointer);
void on_window_realize (GtkWidget*, gpointer);
void on_window_show (GtkWidget*, gpointer);

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

GtkWidget *window;
int a;

/* initialize the GTK+ library */
gtk_init (&argc, &argv);

/* create main window */
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title (GTK_WINDOW (window), "Example");
gtk_container_set_border_width (GTK_CONTAINER (window), 10);
gtk_widget_set_size_request (window, 200, 100);

/* connect signals */
g_signal_connect (G_OBJECT(window), "destroy",
G_CALLBACK (gtk_main_quit), NULL);
g_signal_connect (G_OBJECT(window), "realize",
G_CALLBACK (on_window_realize), NULL);
g_signal_connect (G_OBJECT(window), "map",
G_CALLBACK (on_window_map), NULL);
g_signal_connect (G_OBJECT(window), "show",
G_CALLBACK (on_window_show), NULL);

/* show the main window */
gtk_widget_show (window);

gtk_main ();

return 0;
}

void
on_window_map (GtkWidget *w,gpointer user_data)
{
g_print("Window was mapped.\n");
}

void
on_window_realize (GtkWidget *w,gpointer user_data)
{
g_print("Window was realized.\n");
}

void
on_window_show (GtkWidget *w,gpointer user_data)
{
int x;
g_print("Window was shown.\n");
printf("Insert x : ");
scanf("%d",&x);
}

In the function on_window_show I added the request to insert an integer via terminal, I would like to be asked for it after the window has been showed, what am I missing?

Can you suggest me some good tutorials?

Thanks in advance
Roscarby

[/code]

openldev · Posted: Wed Jun 27, 2007 12:43 pm Post subject:

The problem with this code is that, after the window is set as visible, it is not actually visible immediately. When "show" is emitted, then the window is exposed with "expose-event". So, you should use the "event-after" signal, checking whether the expose-event is done. For example:

Code: (Plaintext)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19	g_signal_connect (G_OBJECT(window), "event-after", G_CALLBACK (on_event_after), NULL); /* ... / void on_event_after (GtkWidget widget, GdkEvent *event, gpointer user_data) { if (event->type == GDK_EXPOSE) { int x; g_print("Window was shown & exposed.\n"); printf("Insert x : "); scanf("%d",&x); } }

roscarby · Familiar Face Joined: 27 Jun 2007 Posts: 5

Thanks a lot for your hint, this is a good step forward, but I realized that
I have been asked for "x" each time I minimize and maximize again the
window, how can I avoid this and being asked for x only once?

Thanks again for the patience
Roscarby

caracal · Posted: Thu Jul 05, 2007 7:12 pm Post subject:

Are you saying that you want the "Window" to show and then have the terminal ask you for input?

If this is the case then you need to free your terminal i would look into using threads and dbus.

openldev · Posted: Thu Jul 05, 2007 7:22 pm Post subject:

No, you don't have to. However, the terminal will block the GUI.

roscarby · Familiar Face Joined: 27 Jun 2007 Posts: 5

Yes this was my problem,
in another post
http://www.gtkforums.com/viewtopic.php?t=709

I exposed the problem, I first tried to solve with
idle function, but i realized this was locking the gtk loop,
so I used threads. I am a newbye with both C and GTK+
particularly I am learning C using the book
"C/C++ von den Grundlagen zur professionellen Programmierung"
from Ulrich Kaiser and Kecher, and when it comes to the graphical
staff, they used some simplified libraries shipped with a CD,
but since I am on linux (cd is 4 windows) I choose to
face the problem by using GTK+.

Thanks for the comments
Roscarby[/url]