I'm not aware of any solution ready to be used out of the box but you can easily accomplish what requested by leveraging libwnck. In the following a quite basic example that catches any maximization on the current screen:
/* gcc $(pkg-config --cflags --libs libwnck-1.0) test.c -o test */
#include <gdk/gdk.h>
#define WNCK_I_KNOW_THIS_IS_UNSTABLE
#include <libwnck/libwnck.h>
static void
geometry_changed(WnckWindow *window)
{
if (wnck_window_is_maximized(window)) {
g_print("A window has been maximized\n");
}
}
static void
window_opened(WnckScreen *screen, WnckWindow *window)
{
g_signal_connect(window, "geometry-changed",
G_CALLBACK(geometry_changed), NULL);
/* Force a geometry-changed emission on already opened windows:
* remove it if you need to catch only *new* maximizations */
geometry_changed(window);
}
gint
main(gint argc, gchar *argv[])
{
GMainLoop *loop;
WnckScreen *screen;
gdk_init(&argc, &argv);
screen = wnck_screen_get(0);
g_signal_connect(screen, "window-opened",
G_CALLBACK(window_opened), NULL);
loop = g_main_loop_new(NULL, FALSE);
g_main_loop_run(loop);
g_main_loop_unref(loop);
return 0;
}
Addendum
If you want to know when the window focus changes, you can connect a callback to the active-window-changed
signal of the relevant WnckScreen
, such as in the following untested snippet:
static void
active_window_changed(WnckScreen *screen)
{
WnckWindow *active_window = wnck_screen_get_active_window(screen);
if (wnck_window_is_maximized(active_window)) {
g_print("The active window is maximized\n");
}
}
...
g_signal_connect(screen, "active-window-changed",
G_CALLBACK(active_window_changed), NULL);
...