A QR Code is a matrix (two-dimensional) barcode. Arbitrary content may be encoded, with URLs being a popular choice :)
Each QR Code contains error recovery information to aid reading damaged or obscured codes. There are four levels of error recovery: Low, medium, high and highest. QR Codes with a higher recovery level are more robust to damage, at the cost of being physically larger.
import qrcode "github.com/skip2/go-qrcode"
Create a PNG image:
var png byte png, err := qrcode.Encode("https://example.org", qrcode.Medium, 256)
Create a PNG image and write to a file:
err := qrcode.WriteFile("https://example.org", qrcode.Medium, 256, "qr.png")
Both examples use the
qrcode.Medium error Recovery Level and create a 256x256 pixel, black on white QR Code.
The maximum capacity of a QR Code varies according to the content encoded and
the error recovery level. The maximum capacity is 2,953 bytes, 4,296
alphanumeric characters, 7,089 numeric digits, or a combination of these.