QRCode Generator in Rust

New Series in Rust 🦀

Today I posted a new video on YouTube (PLEASE SUBSCRIBE 🙌) in Portuguese talking about how to develop a QR Code generator and here I’ll leave the step by step in case you’re interested in seeing how I did it, but the instructions should be in English:

First, I started by choosing a very simple library that provides everything we need qrcode, the name is quite self-explanatory, and the rest of the code isn’t very complicated. I started by creating my new package:

cargo new rust-qrcode-generator

Inside it, I added the new lib to Cargo.toml:

[package]
name = "rust-qrcode-generator"
version = "0.1.0"``
edition = "2021"

[dependencies]
qrcode = "0.13"

Then I ran cargo build to install our library.

After that, I started with the imports we need in our main.rs:

use qrcode::QrCode;
use qrcode::render::unicode;
use std::io;

After that, I started with the input part, and it’s important to note that we need std::io to be able to use the read_line function and actually get the data and confirmation of what we want to generate:

fn main() {
    println!("Enter the string to generate QR code:");

    let mut input = String::new();

    io::stdin().read_line(&mut input).expect("Failed to read line");

    let input = input.trim();

    println!("Do you want to generate a QR code for the following input? (y/n)");

    let mut confirmation = String::new();

    io::stdin()
        .read_line(&mut confirmation)
        .expect("Failed to read line");
}

After that, I started with the logic we’ll use, which is to check if we really want to create a new QR Code and draw it using the qrcode lib, note that we start by defining a unicode to segment the dots and then we start tracing the separations between dark and light, after that we build it and actually return the new image:

if confirmation.trim().to_lowercase() == "y" {
    let code = QrCode::new(input).unwrap();
    let image = code
        .render::<unicode::Dense1x2>()
        .dark_color(unicode::Dense1x2::Light)
        .light_color(unicode::Dense1x2::Dark)
        .build();

    println!("{}", image);
} else {
    println!("QR code generation canceled.");
}

The entire code looks like this:

use qrcode::QrCode;
use qrcode::render::unicode;
use std::io;

fn main() {
    println!("Enter the string to generate QR code:");

    let mut input = String::new();

    io::stdin().read_line(&mut input).expect("Failed to read line");

    let input = input.trim();

    println!("Do you want to generate a QR code for the following input? (y/n)");

    let mut confirmation = String::new();

    io::stdin()
        .read_line(&mut confirmation)
        .expect("Failed to read line");

    if confirmation.trim().to_lowercase() == "y" {
        let code = QrCode::new(input).unwrap();
        let image = code
            .render::<unicode::Dense1x2>()
            .dark_color(unicode::Dense1x2::Light)
            .light_color(unicode::Dense1x2::Dark)
            .build();

        println!("{}", image);
    } else {
        println!("QR code generation canceled.");
    }
}

And below is the desired output:

Well, that’s it! See ya! 🙃