qrcode-rust/src/lib.rs

//! QRCode encoder
//!
//! This crate provides a QR code and Micro QR code encoder for binary data.
//!
//! ```
//! extern crate image;
//! extern crate qrcode;
//!
//! use image::GrayImage;
//! use qrcode::QrCode;
//!
//! # fn main() {
//!
//! let code = QrCode::new(b"Some content here.");
//! match code {
//!     Err(err) => panic!("Failed to encode the QR code: {:?}", err),
//!     Ok(code) => {
//!         let image: GrayImage = code.render().min_width(100).to_image();
//!         // render `image`...
//!     }
//! }
//!
//! # }
//! ```
//!

#![cfg_attr(feature="bench", feature(test))] // Unstable libraries

#[cfg(feature="bench")] extern crate test;
extern crate num_traits;
#[cfg(feature="image")] extern crate image;

use std::ops::Index;

pub mod types;
pub mod bits;
pub mod optimize;
pub mod ec;
pub mod canvas;
pub mod render;

pub use types::{QrResult, EcLevel, Version};

#[cfg(feature="image")] use render::{BlankAndWhitePixel, Renderer};

/// The encoded QR code symbol.
#[derive(Clone)]
pub struct QrCode {
    content: Vec<bool>,
    version: Version,
    ec_level: EcLevel,
    width: usize,
}

impl QrCode {
    /// Constructs a new QR code which automatically encodes the given data.
    ///
    /// This method uses the "medium" error correction level and automatically
    /// chooses the smallest QR code.
    ///
    ///     use qrcode::QrCode;
    ///
    ///     let code = QrCode::new(b"Some data").unwrap();
    ///
    pub fn new<D: AsRef<[u8]>>(data: D) -> QrResult<QrCode> {
        QrCode::with_error_correction_level(data, EcLevel::M)
    }

    /// Constructs a new QR code which automatically encodes the given data at a
    /// specific error correction level.
    ///
    /// This method automatically chooses the smallest QR code.
    ///
    ///     use qrcode::{QrCode, EcLevel};
    ///
    ///     let code = QrCode::with_error_correction_level(b"Some data", EcLevel::H).unwrap();
    ///
    pub fn with_error_correction_level<D: AsRef<[u8]>>(data: D, ec_level: EcLevel) -> QrResult<QrCode> {
        let bits = try!(bits::encode_auto(data.as_ref(), ec_level));
        QrCode::with_bits(bits, ec_level)
    }

    /// Constructs a new QR code for the given version and error correction
    /// level.
    ///
    ///     use qrcode::{QrCode, Version, EcLevel};
    ///
    ///     let code = QrCode::with_version(b"Some data", Version::Normal(5), EcLevel::M).unwrap();
    ///
    /// This method can also be used to generate Micro QR code.
    ///
    ///     use qrcode::{QrCode, Version, EcLevel};
    ///
    ///     let micro_code = QrCode::with_version(b"123", Version::Micro(1), EcLevel::L).unwrap();
    ///
    pub fn with_version<D: AsRef<[u8]>>(data: D, version: Version, ec_level: EcLevel) -> QrResult<QrCode> {
        let mut bits = bits::Bits::new(version);
        try!(bits.push_optimal_data(data.as_ref()));
        try!(bits.push_terminator(ec_level));
        QrCode::with_bits(bits, ec_level)
    }

    /// Constructs a new QR code with encoded bits.
    ///
    /// Use this method only if there are very special need to manipulate the
    /// raw bits before encoding. Some examples are:
    ///
    /// * Encode data using specific character set with ECI
    /// * Use the FNC1 modes
    /// * Avoid the optimal segmentation algorithm
    ///
    /// See the `Bits` structure for detail.
    ///
    ///     #![allow(unused_must_use)]
    ///
    ///     use qrcode::{QrCode, Version, EcLevel};
    ///     use qrcode::bits::Bits;
    ///
    ///     let mut bits = Bits::new(Version::Normal(1));
    ///     bits.push_eci_designator(9);
    ///     bits.push_byte_data(b"\xca\xfe\xe4\xe9\xea\xe1\xf2 QR");
    ///     bits.push_terminator(EcLevel::L);
    ///     let qrcode = QrCode::with_bits(bits, EcLevel::L);
    ///
    pub fn with_bits(bits: bits::Bits, ec_level: EcLevel) -> QrResult<QrCode> {
        let version = bits.version();
        let data = bits.into_bytes();
        let (encoded_data, ec_data) = try!(ec::construct_codewords(&*data, version, ec_level));
        let mut canvas = canvas::Canvas::new(version, ec_level);
        canvas.draw_all_functional_patterns();
        canvas.draw_data(&*encoded_data, &*ec_data);
        let canvas = canvas.apply_best_mask();
        Ok(QrCode {
            content: canvas.to_bools(),
            version: version,
            ec_level: ec_level,
            width: version.width() as usize,
        })
    }

    /// Gets the version of this QR code.
    pub fn version(&self) -> Version {
        self.version
    }

    /// Gets the error correction level of this QR code.
    pub fn error_correction_level(&self) -> EcLevel {
        self.ec_level
    }

    /// Gets the number of modules per side, i.e. the width of this QR code.
    ///
    /// The width here does not contain the quiet zone paddings.
    pub fn width(&self) -> usize {
        self.width
    }

    /// Gets the maximum number of allowed erratic modules can be introduced
    /// before the data becomes corrupted. Note that errors should not be
    /// introduced to functional modules.
    pub fn max_allowed_errors(&self) -> usize {
        ec::max_allowed_errors(self.version, self.ec_level).unwrap()
    }

    /// Checks whether a module at coordinate (x, y) is a functional module or
    /// not.
    pub fn is_functional(&self, x: usize, y: usize) -> bool {
        canvas::is_functional(self.version, self.version.width(), x as i16, y as i16)
    }

    /// Converts the QR code into a human-readable string. This is mainly for
    /// debugging only.
    pub fn to_debug_str(&self, on_char: char, off_char: char) -> String {
        let width = self.width;
        let mut k = 0;
        let mut res = String::with_capacity(width * (width + 1));
        for _ in 0 .. width {
            res.push('\n');
            for _ in 0 .. width {
                res.push(if self.content[k] { on_char } else { off_char });
                k += 1;
            }
        }
        res
    }

    /// Converts the QR code to a vector of booleans. Each entry represents the
    /// color of the module, with "true" means dark and "false" means light.
    pub fn to_vec(&self) -> Vec<bool> {
        self.content.clone()
    }

    /// Converts the QR code to a vector of booleans. Each entry represents the
    /// color of the module, with "true" means dark and "false" means light.
    pub fn into_vec(self) -> Vec<bool> {
        self.content
    }

    /// Renders the QR code into an image. The result is an image builder, which
    /// you may do some additional configuration before copying it into a
    /// concrete image.
    ///
    /// # Examples
    ///
    /// ```
    /// # extern crate image;
    /// # extern crate qrcode;
    /// # use qrcode::QrCode;
    /// # use image::Rgb;
    /// # fn main() {
    ///
    /// let image = QrCode::new(b"hello").unwrap()
    ///                     .render()
    ///                     .dark_color(Rgb { data: [0, 0, 128] })
    ///                     .light_color(Rgb { data: [224, 224, 224] }) // adjust colors
    ///                     .quiet_zone(false)      // disable quiet zone (white border)
    ///                     .min_width(300)         // sets minimum image size
    ///                     .to_image();
    ///
    /// # }
    /// ```
    ///
    /// Note: the `image` crate itself also provides method to rotate the image,
    /// or overlay a logo on top of the QR code.
    #[cfg(feature="image")]
    pub fn render<P: BlankAndWhitePixel + 'static>(&self) -> Renderer<P> {
        let quiet_zone = if self.version.is_micro() { 2 } else { 4 };
        Renderer::new(&self.content, self.width, quiet_zone)
    }
}

impl Index<(usize, usize)> for QrCode {
    type Output = bool;

    fn index(&self, (x, y): (usize, usize)) -> &bool {
        let index = y * self.width + x;
        &self.content[index]
    }
}

#[cfg(test)]
mod tests {
    use {QrCode, Version, EcLevel};

    #[test]
    fn test_annex_i_qr() {
        // This uses the ISO Annex I as test vector.
        let code = QrCode::with_version(b"01234567", Version::Normal(1), EcLevel::M).unwrap();
        assert_eq!(&*code.to_debug_str('#', '.'), "\n\
                    #######..#.##.#######\n\
                    #.....#..####.#.....#\n\
                    #.###.#.#.....#.###.#\n\
                    #.###.#.##....#.###.#\n\
                    #.###.#.#.###.#.###.#\n\
                    #.....#.#...#.#.....#\n\
                    #######.#.#.#.#######\n\
                    ........#..##........\n\
                    #.#####..#..#.#####..\n\
                    ...#.#.##.#.#..#.##..\n\
                    ..#...##.#.#.#..#####\n\
                    ....#....#.....####..\n\
                    ...######..#.#..#....\n\
                    ........#.#####..##..\n\
                    #######..##.#.##.....\n\
                    #.....#.#.#####...#.#\n\
                    #.###.#.#...#..#.##..\n\
                    #.###.#.##..#..#.....\n\
                    #.###.#.#.##.#..#.#..\n\
                    #.....#........##.##.\n\
                    #######.####.#..#.#..");
    }

    #[test]
    fn test_annex_i_micro_qr() {
        let code = QrCode::with_version(b"01234567", Version::Micro(2), EcLevel::L).unwrap();
        assert_eq!(&*code.to_debug_str('#', '.'), "\n\
                    #######.#.#.#\n\
                    #.....#.###.#\n\
                    #.###.#..##.#\n\
                    #.###.#..####\n\
                    #.###.#.###..\n\
                    #.....#.#...#\n\
                    #######..####\n\
                    .........##..\n\
                    ##.#....#...#\n\
                    .##.#.#.#.#.#\n\
                    ###..#######.\n\
                    ...#.#....##.\n\
                    ###.#..##.###");
    }
}

#[cfg(all(test, feature="image"))]
mod image_tests {
    use image::{GrayImage, Rgb, load_from_memory};
    use {QrCode, Version, EcLevel};

    #[test]
    fn test_annex_i_qr_as_image() {
        let code = QrCode::new(b"01234567").unwrap();
        let image: GrayImage = code.render().to_image();
        let expected = load_from_memory(include_bytes!("test_annex_i_qr_as_image.png")).unwrap().to_luma();
        assert_eq!(image.dimensions(), expected.dimensions());
        assert_eq!(image.into_raw(), expected.into_raw());
    }

    #[test]
    fn test_annex_i_micro_qr_as_image() {
        let code = QrCode::with_version(b"01234567", Version::Micro(2), EcLevel::L).unwrap();
        let image = code.render().min_width(200)
                                 .dark_color(Rgb { data: [128, 0, 0] })
                                 .light_color(Rgb { data: [255, 255, 128] })
                                 .to_image();
        let expected = load_from_memory(include_bytes!("test_annex_i_micro_qr_as_image.png")).unwrap().to_rgb();
        assert_eq!(image.dimensions(), expected.dimensions());
        assert_eq!(image.into_raw(), expected.into_raw());
    }
}