Re: Asterisks in barcode human readable text

On 04/13/2015 01:35 PM, Tim Roberts wrote:
> Adrian Klaver wrote:
>> On 04/13/2015 10:20 AM, Andy Robinson wrote:
>>> The problem here is that nobody at ReportLab is a bar code specialists
>>> - quite a lot of this code was contributed or copied from other
>>> libraries years ago - and we don't know whether it is actually correct
>>> or not to allow these characters in this position.  If you have time
>>> to check the specifications, and/or there is evidence that other
>>> libraries do this, we could modify humanText to make life easier.
>> Well from the sidelines and having debugged barcode issues I would say
>> all characters specified in the code should be shown in human readable
>> output.
>
> This is not a slam-dunk obvious decision.  The ISO and ANSI standards
> for Code39 all cost money, so I don't know what the actual
> specifications require.
>
> Technically, the * character is NOT included in the code.  It is the
> Start/Stop symbol.  If you want to include "*" in a Code39 string, you
> have to encode it as /J.

The reason I bring this up is that I ran into this issue with Code39 
barcodes in another context. Basically program A was not including the 
stop characters and program B that needed them was choking. Took some 
digging to figure this out. That is why I believe including more 
information is better then not including it. If someone wants to not 
show them in the human readable format they have the option of 
specifying stop=0.

>
> On the other hand, virtually all the examples I can find on the web do
> print the start/stop symbol as * when rendering the human-readable
> text.  That seems like the most common interpretation.
>


-- 
Adrian Klaver
[email protected]