read-adam7-subimage ( byte-reader loading-png pass -- lines )

Vocabulary

images.png

Inputs

byte-reader	an object
loading-png	an object
pass	an object

Outputs

lines

an object

Definition

USING: accessors kernel math ;

IN: images.png

:: read-adam7-subimage
    ( byte-reader loading-png pass -- lines )
    loading-png height>> pass adam7-subimage-height
    :> height loading-png width>> pass adam7-subimage-width
    :> width height width * zero?
    [ B{ } ]
    [ byte-reader loading-png width height read-scanlines ] if ;