qrcode( message::AbstractString
      ; eclevel::ErrCorrLevel = Medium()
      , version::Int = 0
      , mode::Mode = Numeric()
      , mask::Int = -1
      , width::Int=0)

Create a BitArray{2} with the encoded message, with true (1) for the black areas and false (0) as the white ones.

The error correction level eclevel can be picked from four values: Low() (7% of missing data can be restored), Medium() (15%), Quartile() (25%) or High() (30%). Higher levels make denser QR codes.

The version of the QR code can be picked from 1 to 40. If the assigned version is too small to contain the message, the first available version is used.

The encoding mode mode can be picked from five values: Numeric(), Alphanumeric(), Byte(), Kanji() or UTF8(). If the assigned mode is nothing or failed to contain the message, the mode is automatically picked.

The mask pattern mask can be picked from 0 to 7. If the assigned mask is nothing, the mask pattern will picked by the penalty rules.

qrcode(code::QRCode)

Create a QR code matrix by the QRCode object.

Note: It would raise an error if failed to use the specified modeorversion`.

exportqrcode( message::AbstractString
            , path::AbstractString = "qrcode.png"
            ; eclevel::ErrCorrLevel = Medium()
            , version::Int = 0
            , mode::Mode = nothing
            , width::int = 4
            , pixels::Int = 160)

Create an image with the encoded message of approximate size pixels x pixels.

The error correction level eclevel can be picked from four values: Low() (7% of missing data can be restored), Medium() (15%), Quartile() (25%) or High() (30%). Higher levels make denser QR codes.

The version of the QR code can be picked from 1 to 40. If the assigned version is too small to contain the message, the first available version is used.

The encoding mode mode can be picked from four values: Numeric(), Alphanumeric(), Byte(), Kanji() or UTF8(). If the assigned mode is nothing or failed to contain the message, the mode is automatically picked.

The mask pattern mask can be picked from 0 to 7. If the assigned mask is nothing, the mask pattern will picked by the penalty rules.

exportqrcode( code::QRCode
            , path::AbstractString = "qrcode.png"
            ; pixels::Int = 160)

Create an image with the encoded message of approximate size targetsize.

exportqrcode( codes::AbstractVector{QRCode}
            , path::AbstractString = "qrcode.gif"
            ; pixels::Int = 160
            , fps::Int = 2)

Create an animated gif with codes of approximate size targetsize.

The frame rate fps is the number of frames per second.

Note: The codes should have the same size while the other properties can be different.

exportqrcode( msgs::AbstractVector{<:AbstractString}
            , path::AbstractString = "qrcode.gif"
            ; eclevel::ErrCorrLevel = Medium()
            , version::Int = 0
            , mode::Mode = Numeric()
            , mask::Int = -1
            , width::Int = 4
            , targetsize::Int = 5
            , pixels::Int = 160
            , fps::Int = 2)

Create an animated gif with msgs of approximate size pixels x pixels.

The frame rate fps is the number of frames per second.

QRCode

A type that represents a QR code.

Fields

• version::Int: version of the QR code
• mode::Mode: encoding mode of the QR code
• eclevel::ErrCorrLevel: error correction level of the QR code
• mask::Int: mask pattern of the QR code
• message::String: message to be encoded
• border::Int: width of the white border

Abstract type that groups the five supported encoding modes Numeric, Alphanumeric, Byte, Kanji and UTF8.

Encoding mode for messages composed of digits only.

Encoding mode for messages composed of digits, characters A-Z (capital only) , space and % * + - . / : $.

Encoding mode for messages composed of one-byte characters(unicode range from 0x00 to 0xff, including ISO-8859-1 and undefined characters)

Encoding mode for messages composed of Shift JIS(Shift Japanese Industrial Standards) characters.

Encoding mode for messages composed of utf-8 characters.

Abstract type that groups the four error correction levels Low, Medium, Quartile and High.

Error correction level that can restore up to 7% of missing codewords.

Error correction level that can restore up to 15% of missing codewords.

Error correction level that can restore up to 25% of missing codewords.

Error correction level that can restore up to 30% of missing codewords.

Data structure to encode polynomials to generate the error correction codewords.

generator_matrix(msglen::Int, necwords::Int)

Create the generator matrix of size (msglen + necwords, msglen).

The generator matrix G is of the form

[ * ]
[ I ]

where I is the identity matrix of size msglen and * is computed by the remainder polynomials.

Note that we use a reversed version of generator matrices, i.e. the coefficients is stored in the reverse order, e.g. a0, ..., an.

In this sense, we still have G⋅x = c, where x is the message polynomial and c is the received polynomial.

To get an ordinary generator matrix, just rotate it by 180 degrees, i.e. @view(G[end:-1:1, end:-1:1])

geterrcode(f::Poly, n::Int)

Return a polynomial containing the n error correction codewords of f.

unicodeplot(mat::AbstractMatrix{Bool}; border=:none)

Uses UnicodePlots.jl to draw the matrix.

Note: In UnicodePlots.jl, matrix index start from the left-down corner.

unicodeplot(message::AbstractString
          ; border=:none)

Uses UnicodePlots.jl to draw the QR code of message.

unicodeplotbychar(mat::AbstractMatrix)

Plot of the QR code using Unicode characters.

The value 1(true) represents a dark space and 0(false) a white square. It is the same convention as QR code and is the opposite of general image settings.

unicodeplotbychar(message::AbstractString)

Plot of the QR code using Unicode characters.

imageinqrcode( code::QRCode
             , img::AbstractMatrix{Bool}
             ; rate::Real=1
             , singlemask::Bool=true
             , leftop::Tuple{Int, Int}=(-1, -1)
             , fillalignment::Bool=false
             ) where T <: Union{Bool, Nothing}

Plot image inside QR code.

Arguments

• code::QRCode: QR code
• img::AbstractMatrix{Bool}: image to be plotted
• rate::Real=1: damage rate of the error correction codewords
• singlemask::Bool=true: use the default mask pattern
• leftop::Tuple{Int,Int}=(-1, -1): left top corner of the image