Is it possible to decode incomplete QR Code?

I have an incomplete QRCode (about 30%). Is it possible to decode j开发者_开发知识库ust the fragment of it? I would really like a code snippet - the language doesn't matter.

If you mean, can you decode the entire contents of a QR code even if part of the code is obscured or changed, then yes you can -- sometimes.

QR codes can be encoded with varying levels of redundancy, which are known as levels L, M, Q and H, and correspond to about 7%, 15%, 25% and 30% redundancy. This means you can lose up to that much of the barcode and still decode it. The more you lose, the harder it is to decode, but remains possible within those limits.

Note that certain regions of the QR code can't be lost. The finder patterns (squares at corners) must be findable; they can tolerate some distortion but there's no error correction to help that. Also, the regions around the finder patterns encode format and version. They have a different redundancy (2x encoding using BCH, not Reed-Solomon), but, if you lose too much of those tiny areas you'll not be able to decode, regardless of the main error correction.