qrcode = “0.14.1”
image = “0.25.5”
use qrcode::QrCode;
use image::Luma;
fn main() {
let code = QrCode::new(b"https://google.com").unwrap();
let image = code.render::<Luma<u8>>().build();
image.save("./data/qrcode.png").unwrap();
let string = code.render()
.light_color(' ')
.dark_color('#')
.build();
println!("{}", string);
}

うーん、なるほど…