# File gtk/sample/gtk-demo/drawingarea.rb, line 200
    def scribble_motion_notify_event(widget, event)
      unless @pixmap
        # paranoia check, in case we haven't gotten a configure event
        return false
      end

      # This call is very important; it requests the next motion event.
      # If you don't call Gdk::Window#pointer you'll only get
      # a single motion event. The reason is that we specified
      # Gdk::POINTER_MOTION_HINT_MASK to Gtk::Widget#set_events.
      # If we hadn't specified that, we could just use event.x, event.y
      # as the pointer location. But we'd also get deluged in events.
      # By requesting the next event as we handle the current one,
      # we avoid getting a huge number of events faster than we
      # can cope.
      
      win, x, y, state = event.window.pointer

      if (state & Gdk::Window::BUTTON1_MASK) != 0
        draw_brush(widget, x, y)
      end

      # We've handled it, stop processing
      return true
    end