[barcode] Fwd: Different strings give same barcode

[Matthew Price]

Resending, not sure what happened to the original.

---------- Forwarded message ----------
From: Matthew Price <mandtprice@gmail.com>
Date: May 17, 2005 12:03 PM
Subject: Different strings give same barcode
To: barcode@lists.linux.it


Howdy;

I am new to the list and not even that far with barcoding.  I have an
inhouse application that prints a list of tasks with a barcode to the
left that the data-entry clerks to use to bring up the task later to
note any changes made by the technician.  I am using barcode(1) to
make an EPS which is piped to convert(1) to make a PNG that is cached
in a big directory until job sheets need to be printed.

Everything seemed to be going okay until a clerk noticed that some of
the barcodes would scan into the wrong task number.  I verified by
hand that it is barcode(1) that is producing the incorrect output, at
least as I am running it.

I don't know what I'm doing.  I just read the docs and tried to
replace what I have with the example info.  Below is an example with
output as it appears on my system.  There are other numbers that also
dupe.  I want upc-e, without text, with checksum for a six digit
string output as EPS.  The example is for "058764" and "058706" but
there are others in my application that do the same thing.  I used
md5sum on my cache directory to find the dupes, but that doesn't help
figure out what I'm doing wrong.

Any help at all would be appreciated.

Please try this and tell me if I am crazy:

$  barcode -En  -e upc-e -b 058764
%!PS-Adobe-2.0 EPSF-1.2
%%Creator: libbarcode
%%BoundingBox: 0 0 80 100
%%EndComments
% Printing barcode for "058764", scaled  1.00, encoded using "UPC-E"
% The space/bar succession is represented by the following widths (space first):
% 9111112312313121131211142311111111
[
%  height  xpos   ypos  width       height  xpos   ypos  width
   [80.00  19.50  10.00  0.85]      [80.00  21.50  10.00  0.85]
   [80.00  23.50  10.00  0.85]      [80.00  27.50  10.00  2.85]
   [80.00  31.00  10.00  1.85]      [80.00  35.50  10.00  0.85]
   [80.00  39.50  10.00  0.85]      [80.00  42.50  10.00  0.85]
   [80.00  45.50  10.00  2.85]      [80.00  49.00  10.00  1.85]
   [80.00  51.50  10.00  0.85]      [80.00  55.00  10.00  3.85]
   [80.00  60.50  10.00  2.85]      [80.00  63.50  10.00  0.85]
   [80.00  65.50  10.00  0.85]      [80.00  67.50  10.00  0.85]
   [80.00  69.50  10.00  0.85]
]       { {} forall setlinewidth moveto 0 exch rlineto stroke} bind forall
% End barcode for "058764"


$ barcode -En  -e upc-e -b 058706
%!PS-Adobe-2.0 EPSF-1.2
%%Creator: libbarcode
%%BoundingBox: 0 0 80 100
%%EndComments
% Printing barcode for "058706", scaled  1.00, encoded using "UPC-E"
% The space/bar succession is represented by the following widths (space first):
% 9111112312313121131211142311111111
[
%  height  xpos   ypos  width       height  xpos   ypos  width
   [80.00  19.50  10.00  0.85]      [80.00  21.50  10.00  0.85]
   [80.00  23.50  10.00  0.85]      [80.00  27.50  10.00  2.85]
   [80.00  31.00  10.00  1.85]      [80.00  35.50  10.00  0.85]
   [80.00  39.50  10.00  0.85]      [80.00  42.50  10.00  0.85]
   [80.00  45.50  10.00  2.85]      [80.00  49.00  10.00  1.85]
   [80.00  51.50  10.00  0.85]      [80.00  55.00  10.00  3.85]
   [80.00  60.50  10.00  2.85]      [80.00  63.50  10.00  0.85]
   [80.00  65.50  10.00  0.85]      [80.00  67.50  10.00  0.85]
   [80.00  69.50  10.00  0.85]
]       { {} forall setlinewidth moveto 0 exch rlineto stroke} bind forall
% End barcode for "058706"