You can also define draw_actor_hp in the Window_Enemy_Hud instead of using the def inherited from Window_Base, like so:
class Window_Enemy_Hud < Window_Base
def draw_actor_hp(actor, x, y, width = 124)
# Just the gauge
draw_gauge(x, y, width, actor.hp_rate, hp_gauge_color1, hp_gauge_color2)
end
end
Example.
EDIT: And from scanning over the Neo Gauge script, you'd have to use this definition instead:
def draw_actor_hp(actor, x, y, width = 124)
gwidth = width * actor.hp / actor.mhp
cg = neo_gauge_back_color
c1, c2, c3 = cg[0], cg[1], cg[2]
draw_neo_gauge(x + HPMP_GAUGE_X_PLUS, y + line_height - 8 +
HPMP_GAUGE_Y_PLUS, width, HPMP_GAUGE_HEIGHT, c1, c2, c3)
(1..3).each {|i| eval("c#{i} = HP_GCOLOR_#{i}")}
draw_neo_gauge(x + HPMP_GAUGE_X_PLUS, y + line_height - 8 +
HPMP_GAUGE_Y_PLUS, gwidth, HPMP_GAUGE_HEIGHT, c1, c2, c3, false, false,
width, 30)
end