(local {: pal : gs-to-rgb} (require :editor.tiledraw.iigs))

{:map-bitxy (fn [self x y]
  (let [ibyte (+ (* y 8) (bit.rshift x 1))
        ibit (match (% x 2) 0 4 1 0)]
    (values ibyte ibit 0x0f)))
 :pixel-color (fn [self b] (gs-to-rgb (. pal (+ b 1))))
 :draw-bits #(- $1.icolor 1)
 :palette #(icollect [_ color (ipairs pal)] (gs-to-rgb color))
 :pixel-storage-divisor #2
}