GtkWidget::set_usize
void set_usize(int 
width, int 
height);
 
    
     Requests that the widget's size be changed to 
     width pixels wide by 
     height pixels high.
    
    
     This method is DEPRECATED. It should not be used in any newly
     written code and should be phased out of any existing code.
     Instead used 
set_size_request() .