type document  // abstract type for a document object
type context

@val external document: document = "document"
@val external window: Dom.element = "window"

@send external getElementById: (document, string) => Dom.element = "getElementById"
@send external getContext: (Dom.element, string) => context = "getContext"

@send external fillRect: (context, int, int, int, int) => unit = "fillRect"
@set external fillStyle: (context, string) => unit = "fillStyle"

type key_event = {
  keyCode: int,
  key: string,
}

@send external addKeyEventListener: (Dom.element, string, key_event => unit, bool) => unit = "addEventListener"

type intervalID

@val external setInterval: (unit => unit, int) => intervalID = "setInterval"

type image

@new external newImage: unit => image = "Image"
@set external setImgSrc: (image, string) => unit = "src"
@set external imgOnload: (image, unit => unit) => unit = "onload"

@send external drawImage2: (context, image, int, int) => unit = "drawImage"
@send external drawImage4: (context, image, int, int, int, int) => unit = "drawImage"
@send external drawImage8: (context, image, int, int, int, int, int, int, int, int) => unit = "drawImage"

@set external imageSmoothingEnabled: (context, bool) => unit = "imageSmoothingEnabled"