The MagPi - February 2020

void end_program (GtkWidget *wid,

gpointer ptr)

{

gtk_main_quit ();

}

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

{

gtk_init (&argc, &argv);

GtkBuilder *builder = gtk_builder_new ();

gtk_builder_add_from_file (builder,

"mylayout.glade", NULL);

GtkWidget *win = (

GtkWidget *) gtk_builder_get_object (

builder, "window1");

GtkWidget *btn = (

GtkWidget *) gtk_builder_get_object (

builder, "button1");

g_signal_connect (btn, "clicked",

G_CALLBACK (end_program), NULL);

gtk_widget_show_all (win);

gtk_main ();

}

This time, we also get the button widget from the
builder and connect the end_program callback to it
with g_signal_connect, as before. Build and run,
and this time the button should close the program.

Using layout files can make the amount of code

you need to write a lot shorter, and the use of

Glade makes it easier to create complex

interfaces with more customisation of your

widgets. For small applications with a simple

window, it’s probably more straightforward just

to do everything in C, but for anything more

complex, using a layout file can make the code a

lot more readable.

Next steps

One thing which should be obvious to anyone who

has worked through this book and reached this

point is that GTK is a fairly huge subject! There

are dozens of widgets, and hundreds of different

ways they can be configured and used – any

comprehensive guide to using them all would run

into several hundred pages.

The best reference to GTK 2 – and the best

place to find further information if you want

to do more with it – is the official developer

documentation, which can be found online at

magpi.cc/gtk2manual. This gives far more detail

on every aspect of GTK – the reference section

listing all the functions associated with each

widget is particularly useful.

Hopefully this series of tutorials has given

you an idea of where to get started with GTK

programming, and enough of a foothold to be able

to experiment for yourself.

Happy GUI designing!

Figure 4 With a label

and a button added

Figure 5 The widget

properties editor

Figure 6 The window

created in Glade

when run

Figure 4 Figure 5

Figure 6

TUTORIAL

Glade layout editor with C and GTK magpi.cc 57