Graphics.Barcode.Code128

A library for generating barcodes in Code 128. Details of the encoding are available at http://en.wikipedia.org/wiki/Code_128. The width of the stripes and the height of the barcode are configurable. Two modes of operation are supported:

• Constructing a PDF directly in a ByteString, and
• Constructing an action in HPDF's Draw monad, for composing the barcode with other information in a PDF.

Documentation

data BarcodeConfig

Controls the size of the generated barcode. All units are in HPDF's internal sizing.

Constructors

BarcodeConfig

Fields

height :: Double

The height of the generated barcode

barWidth :: Double

The width of the narrowest possible bar

data Err

Errors that can occur while constructing a barcode

Constructors

CantEncode Char

The returned character cannot be encoded in Code 128

Instances

Show Err

barcodeSize :: BarcodeConfig -> [Char] -> Either Err (Double, Double)

Determine the width and height of rendering a particular string as a barcode in a particular configuration.

barcodePDF :: BarcodeConfig -> String -> IO ByteString

Generate PDF data containing the barcode for a given string, with the tightest possible bounding box. If the string cannot be encoded in Code 128, an IOError is thrown.

drawBarcode

Arguments

:: BarcodeConfig

How to render the barcode

-> String

The string to encode

-> Point

The origin (lower left) of the barcode on the page

-> Either Err (Draw Point)

Encode a string and construct an action in Draw that will render it as a barcode. The action, if created successfully, will return the opposite corner of the barcode. An error is returned if the string could not be encoded as a Code128 barcode.