QR Decoder
Supports QR code versions 1-40 containing numeric, alphanumeric, or 8-bit
byte data. BCH and Reed-Solomon error correction not implemented.

Note: the image processing is rudimentary. It detects the image origin by
the first black pixel encountered starting from the top-left corner. It
detects the bit pixel width by doing a horizontal and vertical scan from the
origin and finding the smallest run of black pixels. It detects the image
width by finding the last black pixel on a horizontal scan starting from the
origin, and the QR size by dividing this width by the bit pixel width.
This is suitable for online generated pixel perfect QR codes, but may need
some help (pre-processing) for less perfect images.