void gtk_widget_set_events(GtkWidget *widget, gint events);
使用gtk_widget_set_events()要特別小心，因為您直接改變了Widget的事件遮罩，不小心的話有可能破壞了Widget的功能，您可以使用gtk_widget_events()增加一些特別事件的事件遮罩：
void gtk_widget_add_events(GtkWidget *widget, gint events);
gtk_widget_set_events()或gtk_widget_events()必須在Widget實現之前呼叫才有作用，events是GdkEventMask的enum：
typedef enum
{
GDK_EXPOSURE_MASK = 1 << 1,
GDK_POINTER_MOTION_MASK = 1 << 2,
GDK_POINTER_MOTION_HINT_MASK = 1 << 3,
GDK_BUTTON_MOTION_MASK = 1 << 4,
GDK_BUTTON1_MOTION_MASK = 1 << 5,
GDK_BUTTON2_MOTION_MASK = 1 << 6,
GDK_BUTTON3_MOTION_MASK = 1 << 7,
GDK_BUTTON_PRESS_MASK = 1 << 8,
GDK_BUTTON_RELEASE_MASK = 1 << 9,
GDK_KEY_PRESS_MASK = 1 << 10,
GDK_KEY_RELEASE_MASK = 1 << 11,
GDK_ENTER_NOTIFY_MASK = 1 << 12,
GDK_LEAVE_NOTIFY_MASK = 1 << 13,
GDK_FOCUS_CHANGE_MASK = 1 << 14,
GDK_STRUCTURE_MASK = 1 << 15,
GDK_PROPERTY_CHANGE_MASK = 1 << 16,
GDK_VISIBILITY_NOTIFY_MASK = 1 << 17,
GDK_PROXIMITY_IN_MASK = 1 << 18,
GDK_PROXIMITY_OUT_MASK = 1 << 19,
GDK_SUBSTRUCTURE_MASK = 1 << 20,
GDK_SCROLL_MASK = 1 << 21,
GDK_ALL_EVENTS_MASK = 0x3FFFFE
} GdkEventMask;
{
GDK_EXPOSURE_MASK = 1 << 1,
GDK_POINTER_MOTION_MASK = 1 << 2,
GDK_POINTER_MOTION_HINT_MASK = 1 << 3,
GDK_BUTTON_MOTION_MASK = 1 << 4,
GDK_BUTTON1_MOTION_MASK = 1 << 5,
GDK_BUTTON2_MOTION_MASK = 1 << 6,
GDK_BUTTON3_MOTION_MASK = 1 << 7,
GDK_BUTTON_PRESS_MASK = 1 << 8,
GDK_BUTTON_RELEASE_MASK = 1 << 9,
GDK_KEY_PRESS_MASK = 1 << 10,
GDK_KEY_RELEASE_MASK = 1 << 11,
GDK_ENTER_NOTIFY_MASK = 1 << 12,
GDK_LEAVE_NOTIFY_MASK = 1 << 13,
GDK_FOCUS_CHANGE_MASK = 1 << 14,
GDK_STRUCTURE_MASK = 1 << 15,
GDK_PROPERTY_CHANGE_MASK = 1 << 16,
GDK_VISIBILITY_NOTIFY_MASK = 1 << 17,
GDK_PROXIMITY_IN_MASK = 1 << 18,
GDK_PROXIMITY_OUT_MASK = 1 << 19,
GDK_SUBSTRUCTURE_MASK = 1 << 20,
GDK_SCROLL_MASK = 1 << 21,
GDK_ALL_EVENTS_MASK = 0x3FFFFE
} GdkEventMask;
事件遮罩與事件的對應如下（取自 Events 表格三）：
| 遮罩 | 事件類型 |
|---|---|
| GDK_EXPOSURE_MASK | GDK_EXPOSE |
| GDK_POINTER_MOTION_MASK | GDK_MOTION_NOTIFY |
| GDK_POINTER_MOTION_HINT_MASK | N/A |
| GDK_BUTTON_MOTION_MASK | GDK_MOTION_NOTIFY (滑鼠按鈕按下) |
| GDK_BUTTON1_MOTION_MASK | GDK_MOTION_NOTIFY (滑鼠按鈕1按下) |
| GDK_BUTTON2_MOTION_MASK | GDK_MOTION_NOTIFY (滑鼠按鈕2按下) |
| GDK_BUTTON3_MOTION_MASK | GDK_MOTION_NOTIFY (滑鼠按鈕3按下) |
| GDK_BUTTON_PRESS_MASK | GDK_BUTTON_PRESS, GDK_2BUTTON_PRESS, GDK_3BUTTON_PRESS |
| GDK_BUTTON_RELEASE_MASK | GDK_BUTTON_RELEASE |
| GDK_KEY_PRESS_MASK | GDK_KEY_PRESS |
| GDK_KEY_RELEASE_MASK | GDK_KEY_RELEASE |
| GDK_ENTER_NOTIFY_MASK | GDK_ENTER_NOTIFY |
| GDK_LEAVE_NOTIFY_MASK | GDK_LEAVE_NOTIFY |
| GDK_FOCUS_CHANGE_MASK | GDK_FOCUS_IN, GDK_FOCUS_OUT |
| GDK_STRUCTURE_MASK | GDK_CONFIGURE, GDK_DESTROY, GDK_MAP, GDK_UNMAP |
| GDK_PROPERTY_CHANGE_MASK | GDK_PROPERTY_NOTIFY |
| GDK_VISIBILITY_NOTIFY_MASK | GDK_VISIBILITY_NOTIFY |
| GDK_PROXIMITY_IN_MASK | GDK_PROXIMITY_IN |
| GDK_PROXIMITY_OUT_MASK | GDK_PROXIMITY_OUT |
| GDK_SUBSTRUCTURE_MASK | 對子視窗接收 GDK_STRUCTURE_MASK 事件 |
| GDK_ALL_EVENTS_MASK | 所有事件 |
舉個實際的例子來說，GtkWindow預設是不接收滑鼠移動事件，您要使用gtk_widget_events()增加GDK_POINTER_MOTION遮罩，才可以捕捉滑鼠移動事件，例如下面的程式在滑鼠於視窗中移動時，將在標題列中顯示目前的座標值：
- motion.c
#include <gtk/gtk.h>
gboolean motion_event_handler(
GtkWidget *widget, GdkEventMotion *event, gpointer data) {
char pos[20];
sprintf(pos, "(%d, %d)", (int) event->x, (int) event->y);
gtk_window_set_title(GTK_WINDOW(widget), pos);
return FALSE;
}
int main(int argc, char *argv[]) {
GtkWidget *window;
gtk_init(&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
g_signal_connect(GTK_OBJECT(window), "destroy",
G_CALLBACK(gtk_main_quit), NULL);
gtk_widget_add_events(window, GDK_POINTER_MOTION_MASK);
g_signal_connect(GTK_OBJECT(window), "motion_notify_event",
G_CALLBACK(motion_event_handler), NULL);
gtk_widget_show(window);
gtk_main();
return 0;
}
一個執行的畫面如下所示：
