Kewar

Generate a QR code from a given input string. The output of the entry point generate is an array representing the drawable representation of the QR code, meaning a data structure that can be mapped - for instance - to terminal output or images.

The module includes a CLI utility which prints the QR code directly in the terminal as an example.

You can install it via

cabal install exe:kewar

And use it like

kewar "Hello World"
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Documentation

generate :: String -> CorrectionLevel -> Either Exception Grid

Entry point of the library. Attempts generating a QR Code Grid from a given input string.

data CorrectionLevel

Correction Level allows reading QR codes in case they get damaged or unreadable.

Constructors

L

allows up to 7% data recovery

M

allows up to 15% data recovery

Q

allows up to 25% data recovery

H

allows up to 30% data recovery

Instances

Eq CorrectionLevel

Defined in Kewar.Types

Methods

(==) :: CorrectionLevel -> CorrectionLevel -> Bool

(/=) :: CorrectionLevel -> CorrectionLevel -> Bool

Show CorrectionLevel

Defined in Kewar.Types

Methods

showsPrec :: Int -> CorrectionLevel -> ShowS

show :: CorrectionLevel -> String

showList :: [CorrectionLevel] -> ShowS

type Grid = Array Position Module

Array holding the drawable representation of the QR code. It includes encoded data, functional patterns, format, and version bits.

cols :: Grid -> [[(Position, Module)]]

Returns a list of columns for a given grid. Useful for drawing.

rows :: Grid -> [[(Position, Module)]]

Returns a list of rows for a given grid. Useful for drawing.

data Module

A module represent a single unit composing a QR code. We're not using the word pixel as they usually span more than a pixel.

Constructors

Black

Dark module

White

Light module

Instances

Eq Module

Defined in Kewar.Layout.Types

Methods

(==) :: Module -> Module -> Bool

(/=) :: Module -> Module -> Bool

type Position = (Int, Int)

Position of a module in a given grid. It's in the form (row index, column index).