QOI is a Common Lisp library for reading and writing QOI (Quite OK Image Format) files.

decode takes an input stream of octets and decodes it to an image. image is an 1D array of size width * height * channels (channels = 3 for RGB file and = 4 for RGBA file).

To decode a qoi file simply:

(with-open-file (stream #p"./dice.qoi" :element-type '(unsigned-byte 8))
  (decode stream))

decode returns multiple values: (values image width height channels colorspace).

encode takes an binary output stream and an image array then encodes the image and writes it to that stream.

To encode and save an image to output-file simply:

(with-open-file (stream output-file
                        :direction :output
                        :if-exists :supersede
                        :element-type '(unsigned-byte 8))
  (encode stream image width height channels colorspace))

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