# File gtk/sample/gtk-demo/drawingarea.rb, line 158
    def scribble_expose_event(widget, event)
      # We use the 'foreground GC' for the widget since it already exists,
      # but honestly any GC would work. The only thing to worry about
      # is whether the GC has an inappropriate clip region set.
      widget.window.draw_drawable(widget.style.fg_gc(widget.state),
                                  @pixmap,
                                  # Only copy the area that was exposed.
                                  event.area.x, event.area.y,
                                  event.area.x, event.area.y,
                                  event.area.width, event.area.height)
      return false
    end