Re: Simple Gtk app.

[Jose Eusebio Roza Pando <jeroza alu uah es>]

I do not know why it does not work.
I use this and it works fine, but
i do not use either gtk_widget_set_event nor
gtk_widget_add_event .
        Eusebio
Mark Hannah escribió:

> Hi,
>    The part about the callbacks and the signal handler
> make sense to me, but I don't know what the
> "gtk_widget_set[add]_events" part does?
>
> I have copied my program below. The problem is that
> when a key is pressed, the callbacjk function is not
> being run.
>
> I am sure I am doing something silly, I just don't
> know what.
>
> -------------------------------
> -------------------------------
>
> #include <gnome.h>
>
> static void key_press_cb(GtkWidget *widget,
> GdkEventKey* event)
> {
>   // Print the keyvalue pressed.
>   printf("A key has been pressed!\n");
>
>   /* prevent the default handler from being run */
>   gtk_signal_emit_stop_by_name
> (GTK_OBJECT(widget),"key_press_event");
> }
>
> int main(int argc, char* argv[])
> {
>         GtkWidget *window;
>         GtkWidget *image;
>
>         gtk_init(&argc, &argv);
>
>         // Create a new window.
>         window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
>
>         // The keypress callback function.
>
> gtk_signal_connect(GTK_OBJECT(window),"key_press_event",GTK_SIGNAL_FUNC(key_press_cb),NULL);
>
>         gtk_widget_set_events(window, GDK_KEY_PRESS_MASK);
>
>         // Load the image from a file.
>         image = gnome_pixmap_new_from_file("image1.jpg");
>
>         // Test that our image loaded ok.
>         if (image == NULL) printf("Failed to load
> image!\n");
>         else printf("Loaded image!\n");
>
>         // Add the pixmap to the window.
>         gtk_container_add(GTK_CONTAINER(window),image);
>
>         // Set the window size.
>
> gtk_window_set_default_size((GtkWindow*)window,100,100);
>
>         // Display the new window.
>         gtk_widget_show_all(window);
>
>         // The main gnome loop runs forever.
>         gtk_main();
>
>         return(0);
> }
>
> --- Jose Eusebio Roza Pando <jeroza alu uah es> wrote:
> > To interpret the keystrokes you can use the code
> > shown below.
> > I do not know the way to move the pixmap in gtk, but
> > i know
> > that is possible with gtkextra lib. You must create
> > a canvas
> > and you must insert inside a child (a pixmap for
> > example) and
> > move it easily.
> >     Eusebio
> > The code was generated by Carlos Pereira in other
> > mail:
> >
> > These examples should answer your question.
> > Carlos
> >
> > ------------monitor events----------------
> > gtk_widget_set[add]_events (GTK_WIDGET (window),
> > GDK_EXPOSURE_MASK |
> > GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK |
> > GDK_POINTER_MOTION_MASK |
> > GDK_POINTER_MOTION_HINT_MASK |
> > GDK_KEY_PRESS_MASK | GDK_KEY_RELEASE_MASK);
> >
> > --------connect-------------
> > gtk_signal_connect(GTK_OBJECT (window),
> > "key_press_event",
> >
> > GTK_SIGNAL_FUNC(app_gtk_handle_key_press), data);
> >
> > --------callback---------------
> > #include <gdk/gdkkeysyms.h>
> >
> > gint app_gtk_handle_key_press (GtkWidget *widget,
> > GdkEventKey *event,
> > gpointer data)
> > {
> > switch (event->keyval)
> >   {
> >   case GDK_Escape:
> >
> >   case GDK_F2:
> >
> >   case GDK_F3:
> >
> >   case GDK_Page_Down:
> >   }
> >
> > /* prevent the default handler from being run */
> > gtk_signal_emit_stop_by_name
> > (GTK_OBJECT(widget),"key_press_event");
> >
> > return TRUE;
> > }
> >
> > Mark Hannah escribió:
> >
> > > Hi,
> > >     I'm having problems writing a simple Gtk app.
> > >
> > > What I want to do is open a window and place a
> > pixmap
> > > image in the window. I would then like to use the
> > > keyboard arrow keys to move the image around the
> > > window.
> > >
> > > I can get as far as displaying thr pixmap in the
> > > window, but I do not know how to capture and
> > interpret
> > > the keystrokes or move the pixmap position.
> > >
> > > Can anyone help?
> > >
> > > Many thanks,
> > > Mark.
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