Programming and Graphics

8.5 GUI programming withGtk+ 285

Figure 8.5.1 A window produced by the graphics toolkit GTK+. When the button

is clicked, the window disappears.

gtkinit (&argc, &argv);

window = gtkwindownew (GTKWINDOWTOPLEVEL);

gtkcontainersetborderwidth (GTKCONTAINER (window), 100);

button = gtkbuttonnewwithlabel ("Two horses: Jeremy and Zebediah");

gtkcontaineradd (GTKCONTAINER (window), button);

gsignalconnectswapped (GOBJECT (button), "clicked",

GCALLBACK (gtkwidgetdestroy),

GOBJECT (window));

gtkwidgetshow (button);

gtkwidgetshow (window);

gtkmain ();

return 0;

}

GtkWidgetin the fifth and sixth lines is the class type for theGtk+widgets.
Running the code produces the window shown in Figure 8.5.1.

Note the similarities with theGlutdrawing code. Most of theGtk+
commands are self-explanatory. The first and last commands call the functions:

gtkinit(&argc, &argv)

This function parses the window-specific parameters transmitted to the

foundation graphics library or server.

gtkmain()

This function launches the graphics display in an infinite loop that can

be interrupted only by certain events.

InGtk+programming, we first register the callbacks (widgets) and then start