def set_position(x, y)
      d_x = x - @x
      d_y = y - @y
      @x = x; @y = y
      @text_x += d_x
      @text_y += d_y
      @nodes.map! do |n|
        n + d_x
      end
    end
def set_position(x, y)
      d_x = x - @x
      d_y = y - @y
      @x = x; @y = y
      @text_x += d_x
      @text_y += d_y
      @nodes.map! do |n|
        n + d_x
      end
    end
Sets the position of the text field in the screen.

 Parameters:
 [x] The new x-coordinate for the text field.
 [y] The new y-coordinate for the text field.