void (*func_button)(ImageWindow *, GdkEventButton *event, gpointer);
void (*func_drag)(ImageWindow *, GdkEventButton *event, gdouble dx, gdouble dy, gpointer);
void (*func_scroll)(ImageWindow *, GdkEventScroll *event, gpointer);
+ void (*func_focus_in)(ImageWindow *, gpointer);
gpointer data_button;
gpointer data_drag;
gpointer data_scroll;
+ gpointer data_focus_in;
/* scroll notification (for scroll bar implementation) */
void (*func_scroll_notify)(ImageWindow *, gint x, gint y, gint width, gint height, gpointer);