% Code128 -- generate barcodes
% Jessica L. Parsons <orc@pell.portland.or.us>
% Tue Jan 15 14:56:13 PST 2008

#![Code 128](code128.png =264x70)



##Synopsis
`code128` _barwidth_ _string_ `[>` _output-file_`]`

##Description

**Code128** generates barcode images in JPG (or GIF, if you don't
have a copy of `libjpeg` on your system) using
[Boutell.com](http://www.boutell.com)'s
[GD](http://www.boutell.com/gd/) graphics library.  It takes
two arguments -- the width of the smallest bar in the output (typically
1; the title image on this page uses 2) in pixels, and the string you wish
to generate a barcode of.   It encodes that string using the **Code 128**
barcode format, and dumps the resulting image to standard out.


There are approximately a million versions of **GD** out there, but if
your version supports [PNG](https://www.w3.org/TR/PNG/) images, it will
produce a png, otherwise if it supports  [JPEG](http://www.ijg.org/)s,
it will produce a jpeg, otherwise otherwise it will produce a
[GIF](https://medium.com/matt-bors/world-war-g-8b90a02a4432).

##Bugs

 1. **Code 128** format barcodes can get to be fairly long.
    A code 128 barcode is 11 _`barwidth`_ long per character,
    plus 55 barwidth for the message envelope.

##Source Code

**Code128** uses my [configuration](/~orc/Code/configure)
system to configure itself for building on various platforms.  To
build the code, untar the archive, run `configure.sh`, then run
a `make`.

=[version 0.5](code128-0.5.tar.bz2)=
    A fairly major rework on the internals of this code;  first, I
    implemented CODEC (compresses number strings by up to ~50%),
    and secondly I took out all of the places where I was table
    scanning the code128[] array and replaced it with lookups into
    a 3 automatically generated maps (generated by the new program
    `mkcodes`, which is used to make the file `table.c` which contains
    `codeAmap[]`, `codeBmap[]`, and `controlmap[]` (codeC doesn't use
    lookups;  the 100 CODEC points are 0..99 so no lookup is needed.))

=[version 0.4](code128-0.4.tar.bz2)=
    It turns out that when I originally wrote this code I'd completely
    misread the checksum generation algorithm, so instead of code128
    barcodes I was generating orc128 barcodes.  So, as part of a small
    software death march to updating the configuration to work with a
    more uptodate version of libgd (which was a pain because libgd has
    gone not only to GNU autoconfigure, but has -- at least on Unix --
    abandoned make for cmake, so I couldn't even salvage a GNU Makefile.in
    but had to create one from scratch instead) I reworked the checksum
    computation so that it actually works.

    Other features in 0.4 include changing the [copyright](COPYRIGHT.html)
    to a 3-clause BSD-style one and changing the output format of the
    barcode image to (depending on libgd support) PNG, then Jpeg, and
    finally (the finally free-to-use) GIF format.

=[version 0.2](code128-0.2.tar.gz)=
    The first release. It's version 0.2 because version 0.1 didn't include
    the [copyright notice](COPYRIGHT.html).