Bar code generation & readin

Sarah Reichelt sarah.reichelt at gmail.com
Tue Feb 27 06:54:26 EST 2007


On 2/27/07, Peter Alcibiades <palcibiades-first at yahoo.co.uk> wrote:
> Wonder whether someone with experience of bar codes could help with this -
> Sarah??
>
> My bar code reading app now finally seems to work, and the reader is on a Y
> connection with the keyboard (so called Wedge).  All the commercially printed
> codes I've tried work fine, even the most tiny ones, or ones partly obscured
> by a price sticker.  So its a fine reader (Gryphon).  There is just one last
> glitch.
>
> Reading codes we generate doesn't work.  I am using kbarcode, saving them as
> pngs, and then printing on a laser printer on ordinary paper. The great merit
> of kbarcode is of course, it is free and will also do label printing....
>
> I've used code 39 as well as others, makes no odds.  The size of the png also
> makes no odds.  .
>
> Is there some special magic to generating and printing readable bar codes?
>
> Peter
> ____________

Well yes, there IS special magic to generating barcodes :-)
although not to printing as far as I know.

You can't just convert text to a barcode font, it has to have the
special header & footer to identify it's code to the scanner. I
haven't worked with Code39, but for Code128, I made a barcode
generator <http://www.troz.net/Rev/misc/Barcodes.rev.gz> that takes
your text and fills in the special stuff at either end, does any other
processing needed (I think spaces require encoding), then uses a
barcode font to display the final code.

I am not familiar with kbarcode, but I assume it should be doing this also.

Is your reader configured to read Code39? Are you sure the code is
really being generated? If you like to send me the text and the png
off-list, I'd be happy to test with a few different scanners and see
what I can find.

Cheers,
Sarah



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