I am building a code 128C barcode with BWIPP, but ran across a little
problem when using a human readable with a font size larger than the
default one.  The human readable for this barcode seems to be shown in
digit pairs (as per the 128c encoding) but these pairs of digits
overlap one another when I raise the font size, using the following
code:

200 200 moveto (^1050123456789) (includetext textsize=14) code128
barcode

What am I doing wrong?  I want my human readable to be of a size
greater than the default one, but when I do that It will look wrong at
printout.

Thanks,
Jean-François.

You are doing nothing wrong and the effect that you are observing is
intended. However, you can plot the text so that it does not overlap
using code similar to than below:

Hope this helps,

Tez

----

gsave
200 200 translate

% encode the symbol as normal but without displaying text
0 0 moveto (^1050123456789) () code128

% plot barcode but keep copy of data structure
dup barcode

% calculate barcode width by summing the bar and space widths
(sbs) get 0 exch {add} forall

% calculate text width
/Helvetica findfont 14 scalefont setfont
(5483-7277-4828) stringwidth pop

% plot the text at coords ( (barcode width - text width) / 2 , -10 )
sub 2 div -10 moveto (0123456789) show

grestore

I intend to write an auto-encoder for code 128 quite soon and this
will allow you to enter an arbitrary ASCII string for encodation and
to force the alphabet. Until then, I do not have code that does quite
what you want.

However you may find the following code from Stefan Stefanov quite
useful and a basis for developing code to satisfy your requirements:

http://postscriptbarcode.googlecode.com/svn/scripts/Helpers/code128_a...

Hope this helps,

Tez