ehpale / elaphe

Elaphe

Elaphe is a python binding of Barcode Writer In Pure PostScript (http://www.terryburton.co.uk/barcodewriter/). It generates barcode symbol as PostScript code fragment using BWIPP. The generated code is then embedded in encapsulated PostScript image which can be handled by PIL.

Prerequisites

• Python 2.7 or later (functional decorators, ternary operator, and generator expressions are used).

  Note

  Except setup.py test, code may still work on 2.5-2.6.

• If you want to render barcode into bitmap image, EpsImagePlugin of Python Imaging Library (http://www.pythonware.com/products/pil) or Pillow is required. Note that EpsImagePlugin requires Ghostscript is correctly installed.

Simple Usage

The following example:

>>> from elaphe import barcode
>>> barcode('qrcode',
...         'Hello Barcode Writer In Pure PostScript.',
...         options=dict(version=9, eclevel='M'),
...         margin=10, data_mode='8bits'))   # Generates PIL.EpsImageFile instance
<PIL.EpsImagePlugin.EpsImageFile ... at ...>
>>> _.show() # Show rendered bitmap

will invoke some viewer which shows a QRcode symbol with 10px margin.

Remember, barcode() returns PIL image object.

elaphe's Issues

Allow byte and int encoding for DataMatrix

The encoder for DataMatrix code generation accepts only strings as input.
It would be nice if byte and int would be acceptable as well.

Provide wheels

Thanks for providing this useful project, would it be possible to provide wheels on PyPI for releases? They speed up install times for consumers as they remove the need to run code locally as part of the install.

QR code: "ValueError: No appropriate mode"

Please add the following patch, which fixes a typo in eclevel to ecval conversion:

--- elaphe/qrcode.py~   2017-05-03 18:50:22.000000000 +0200
+++ elaphe/qrcode.py    2018-03-12 12:30:58.957870018 +0100
@@ -264,7 +264,7 @@
         n_msgbits = len(mid)+cclen+n_msgbits
 
     # logging.debug('enc=%s fmt=%s eclv=%s ver=%s' % (encoding, format_, eclevel, version))
-    ecval = 'LHQM'.index(eclevel)
+    ecval = 'LMQM'.index(eclevel)
     if version:
         version = str(version)
     for frmt, vers, size, asp2, asp3, nmod, ecws_list, ecb_list in QRCODE_METRIC:

See also:
https://bitbucket.org/whosaysni/elaphe/issues/81/valueerror-no-appropriate-mode-when-using

Does not specify Python version trove classifiers

This project is being highlighted by https://caniusepython3.com/ as not being compatible with Python 3 as it does not have the Python 3 trove classifier.

Broken code128 barcodes

Please see:
https://stackoverflow.com/questions/37800370/python-elaphe-generates-broken-barcodes
The generated code128 barcodes are missing the pixels to the right.

In my case, an 8 digit code is correctly shown by changing the line 83 in code128.py from
return [0, 0, self._count_chars(codestring)*11+2, height*DPI]
to
return [0, 0, self._count_chars(codestring)*13+2, height*DPI]

Code128 generator appends black box

The Code128 generator appends a black box to the right of the generated barcode, causing the code to be read wrongly.

Note the elaphe3 0.2 result below

Compare with the result from http://generator.onbarcode.com

Used with Pillow 5.0.0 library.

pharmacode bbox not calcualted correctly

Hey,

Wanted a pharmacode barcode on labels and landed on this package. But when testing the biggest number possible (131070) I was missing some bars.

 bar = barcode('pharmacode', '131070')
bar.save('elaphe_test_1.jpg')
bar = barcode('pharmacode', '131070', right_margin = 50)
bar.save('elaphe_test_2.jpg')

So looking at the code I first looked at how the widths are defined.

default_options = dict(
            LinearCodeRenderer.default_options,
            height=8*2.835, nwidth=0.5*2.835,
            wwidth=1.5*2.835, swidth=1.0*2.835,
            textyoffset=-7, textsize=10)

These are converted from DPI to DPmm. Was afraid rounding off is a problem. But changing it to intiger values only made the issue worse.

Next looked at the code_box calculation.

def _code_bbox(self, codestring):
            """
            >>> r = Phamacode._Renderer({})
            >>> r._code_bbox('117480')
            [0, 0, 90.72, 22.68]
            """
            return [0, 0, int(math.log(int(codestring), 2))*2*2.835,
                    self.lookup_option('height')]

Here the DPI to DPmm is done again. But when the bar width is changed this is not considered. The main issue is the *2 though. The code here multiplies the number of bars by 2 while they can either be 0.5+1 or 1.5+1 ( +1 for spacer).

Hope this can be fixed.

Render tests fail

Run python setup.py test -s test.render.suite; it's not clear whether these errors are important or not.

Provide support for EAN128 (aka gs1-128)

The barcode.ps file seems to provide support for gs1-128 but I can't get it to work.

Error when generating Code39 barcode containing *

Example:

import io
import elaphe

b = elaphe.barcode('code39', 'ABC*DEF')
b.save(io.BytesIO(), format='png')

Results in:

CalledProcessError: Command '['gs', '-q', '-g144x72', '-r72.000000x72.000000', '-dBATCH', '-dNOPAUSE', '-dSAFER', '-sDEVICE=ppmraw', '-sOutputFile=/tmp/tmp2njjh_ze', '-c', '0 0 translate', '-f', '/tmp/tmp4y2j7fa5', '-c', 'showpage']' returned non-zero exit status 1.

with stderr:

Error: /bwipp.code39badCharacter in null
Additional information: (Code 39 must contain only digits, capital letters, spaces and the symbols -.$/+%)
Current allocation mode is local
GPL Ghostscript 9.50: Unrecoverable error, exit code 1

Yet * is included in elaphe.code39.CODE39_CHARS.

Render tests error on Python 3

Run python setup.py test -s test.render.suite on Python 3, these error around the use of StringIO which no longer exists.

Since these also fail under Python 2 (#8) it's not clear whether this is a quick fix.