Custom meter problem

[daylights]

Hi everyone !
I need to change meter style but I don't find a solution !
I want to make the meter graphic scrolling up and down. **By default it's right to left**
I try to change the direction in this part of script

Code:

#--------------------------------------------------------------------------
  # * Draw HP
  #     actor : actor
  #     x     : draw spot x-coordinate
  #     y     : draw spot y-coordinate
  #     width : draw spot width
  #--------------------------------------------------------------------------
  alias draw_actor_hp_bar draw_actor_hp
  def draw_actor_hp(actor, x, y, width = 144)
    bar_x = HP_Pos_Adjust[0] + x
    bar_y = HP_Pos_Adjust[1] + y + (Font.default_size * 2 /3)
    @skin = RPG::Cache.windowskin(HP_Meter)
    @width  = @skin.width
    @height = @skin.height / 3
    src_rect = Rect.new(0, 0, @width, @height)
    self.contents.blt(bar_x, bar_y, @skin, src_rect)    
    @line   = (actor.hp == actor.maxhp ? 2 : 1)
    @amount = actor.hp.to_f / actor.maxhp.to_f
    src_rect2 = Rect.new(0, @line * @height, @width * @amount, @height)
    self.contents.blt(bar_x, bar_y, @skin, src_rect2)
    draw_actor_hp_bar(actor, x, y, width)
  end