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Diffstat (limited to 'docs/quantum_painter_rle.md')
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| diff --git a/docs/quantum_painter_rle.md b/docs/quantum_painter_rle.md new file mode 100644 index 0000000000..dcb9a1e1a7 --- /dev/null +++ b/docs/quantum_painter_rle.md @@ -0,0 +1,29 @@ +# QMK QGF/QFF RLE data schema :id=qmk-qp-rle-schema + +There are two "modes" to the RLE algorithm used in both [QGF](quantum_painter_qgf.md)/[QFF](quantum_painter_qff.md): + +* Non-repeating sections of octets, with associated length of up to `128` octets +    * `length` = `marker - 128` +    * A corresponding `length` number of octets follow directly after the marker octet +* Repeated octet with associated length, with associated length of up to `128` +    * `length` = `marker` +    * A single octet follows the marker that should be repeated `length` times. + +Decoder pseudocode: +``` +while !EOF +    marker = READ_OCTET() + +    if marker >= 128 +        length = marker - 128 +        for i = 0 ... length-1 +            c = READ_OCTET() +            WRITE_OCTET(c) + +    else +        length = marker +        c = READ_OCTET() +        for i = 0 ... length-1 +            WRITE_OCTET(c) + +``` | 
