Re: measuring time between two buttonclicks

[Olexiy Avramchenko <olexiy irtech cn ua>]

Thomas Deschepper wrote:

> I'm expermimenting a bit with GTK and I wanted to measure the time
> interval between two clicks on a button. I figured out that I had to use
> a GTimer provided by GLib.
>
> The first time the button is clicked, it should initialize and start the
> timer. The second time however, the GTimer should be stopped and the
> interval should be calculated with the appropriate function...
>
> How can I construct my callback so that I can execute this piece of code
> on the first click and that piece of code on the second click??
>  
You can use static boolean flag in callback, like this:

c-source start 
----------------------------------------------------------------------------------------------------

#include <gtk/gtk.h>

static void clicked(GtkWidget *button, GTimer *timer)
{
GtkWidget       *label;
static gboolean first_click=FALSE;

        if ( !first_click ) {
                g_timer_start(timer);
                gtk_label_set_text(GTK_LABEL(label), "Press button one more");
        }
        else {
        gchar *s;
                g_timer_stop(timer);
                s = g_strdup_printf(
                                        "Time between clicks: %.0fs %.0fms %.0fus",
                                        g_timer_elapsed(timer, NULL),
                                        g_timer_elapsed(timer, NULL)*1000,
                                        g_timer_elapsed(timer, NULL)*1000*1000
                );
                gtk_label_set_text(GTK_LABEL(label), s);
                g_free(s);
        }

        first_click = !first_click;
}

int main(int argc, char **argv)
{
GtkWidget       *window;
GtkWidget       *button;
GTimer          *timer;

        gtk_init(&argc, &argv);

        window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
        gtk_container_set_border_width(GTK_CONTAINER(window), 4);
        g_signal_connect(window, "delete-event", G_CALLBACK(gtk_main_quit), 0);

        button = gtk_button_new_with_label("Press button");
        gtk_container_add(GTK_CONTAINER(window), button);
        timer = g_timer_new();
        g_signal_connect(button, "clicked", G_CALLBACK(clicked), timer);

        gtk_widget_show_all(window);

        gtk_main();

        return 0;
}

c-source 
end------------------------------------------------------------------------------------------------------

   Olexiy