type point = float * float
module Scaling : sig ... end
module Viewport : sig ... end
module Font : sig ... end
type thickness = [
  1. | `normal
  2. | `thick
]
type point_shape = [
  1. | `bullet
  2. | `circle
]
module Picture : sig ... end
module Plot : sig ... end
type target = [
  1. | `File of string
  2. | `Channel of out_channel
  3. | `Buffer of Buffer.t
]
module Layout : sig ... end