Barcode::Code128 generates bar codes using the CODE 128 symbology. It can
generate images in PNG or GIF format using the GD package, or it can generate a
text string representing the barcode that you can render using some other
technology if desired.

The intended use of this module is to create a web page with a bar code on it,
which can then be printed out and faxed or mailed to someone who will scan the
bar code. The application which spurred its creation was an expense report tool,
where the employee submitting the report would print out the web page and staple
the receipts to it, and the Accounts Payable clerk would scan the bar code to
indicate that the receipts were received.

The default settings for this module produce a large image that can safely be
FAXed several times and still scanned easily. If this requirement is not
important you can generate smaller image using optional parameters.

If you wish to generate images with this module you must also have the GD.pm
module (written by Lincoln Stein, and available from CPAN) installed.

If the GD module is not present, you can still use the module, but you will not
be able to use its functions for generating images. You can use the barcode()
method to get a string of "#" and " " (hash and space) characters, and use your
own image-generating routine with that as input.