libqrencode

Libqrencode is a fast and compact library for encoding data in a QR Code symbol, a 2D symbology that can be scanned by handy terminals such as a mobile phone with CCD. The capacity of QR Code is up to 7000 digits or 4000 characters and has high robustness.
Libqrencode accepts a string or a list of data chunks then encodes in a QR Code symbol as a bitmap array. While other QR Code applications generate an image file, using libqrencode allows applications to render QR Code symbols from raw bitmap data directly. This library also contains a command-line utility outputs QR Code images in various formats.

参考：https://blog.csdn.net/qq_17623363/article/details/119510683