Description:

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, described below.

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. Version 1.20 or higher of GD generates a PNG file, due to
issues with the GIF patent. If you want to create a GIF, you must use
version 1.19 or earlier of GD. However, most browsers have no trouble
with PNG files.

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.

To use the the GD module, you will need to install it along with this
module. You can obtain it from the CPAN (Comprehensive Perl Archive
Network) repository of your choice under the directory
"authors/id/LDS". Visit http://www.cpan.org/ for more information
about CPAN. The GD home page is:
http://stein.cshl.org/WWW/software/GD/GD.html