read-pgm ( -- image )

Vocabulary

images.pgm

Inputs

None

Outputs

image

an object

Definition

USING: accessors combinators images io kernel make math
specialized-arrays.instances.alien.c-types.ushort ;

IN: images.pgm

:: read-pgm ( -- image )
    read-token :> type read-number :> width read-number
    :> height read-number :> max width height *
    :> npixels max 256 >= :> wide type {
        {
            "P2"
            [
                [ 0 npixels read-numbers ] wide
                [ ushort-array{ } ] [ B{ } ] if make
            ]
        }
        { "P5" [ wide [ 2 ] [ 1 ] if npixels * read ] }
    } case :> data image new L >>component-order
    { width height } >>dim f >>upside-down? data >>bitmap wide
    [ ushort-components ] [ ubyte-components ] if
    >>component-type ;