Fast receipt entry into gnuCash

AC gnucash at acarver.net
Tue Jun 23 14:05:46 EDT 2015


On 2015-06-22 23:40, Liz wrote:
> On Mon, 22 Jun 2015 15:52:58 -0700
> AC <gnucash at acarver.net> wrote:
> 
>> Smartphones or tablets with a camera (or for that matter a desktop or
>> laptop with a camera) and the right software can read QR codes and
>> perform some action.  Currently most software redirects to a website
>> as the QR code likely contains a URL.  However, making software that
>> takes in the data and writes to a file of some standard format
>> wouldn't be much of a change.
> 
> 
> A QR code is a 2-dimensional bar code matrix.
> A bar code is actually based on the principle of Morse Code, using
> thick bars and thin bars and spaces.
> 
> I'm just mentioning this, because there is no magic involved in
> deciphering the codes.

No, a QR code is not a simple 2D bar code.  There is a significant
amount of processing power required to decode a QR or similar 2D barcode
(DataMatrix, Aztec, etc.) starting with using the "bullseyes" to align
and register the code.  But the bullseyes are not part of the data so
you must reconstruct the data around those features.  There's pattern
recognition for each of the regions of the QR code.

Regular 1D barcodes are also not based on Morse Code, it is not simple
on-off.  The data is encoded in the width and spacing of the bars
including the white space for some formats (Interleaved 2 of 5 uses both
white and black space while Code 3 of 9 actually has a mirrored image code).

The only 2D barcode format that is a simple barcode in two dimensions is
PDF 417 which utilizes stacked rows of 1D barcodes.

I've written code to generate QR and DataMatrix barcodes.  They are by
far not simple at all.


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