[#117] Support zbar library that does not provide orientation

README.rst

@@ -210,6 +210,17 @@ symbol types
  >>> decode(Image.open('pyzbar/tests/qrcode.png'), symbols=[ZBarSymbol.CODE128])
  []
 
+ZBar versions
+-------------
+
+Development of the `original zbar <http:https://zbar.sourceforge.net/>`__ stopped in 2012.
+Development was started again in 2019 under a `new project <https://github.com/mchehab/zbar/>`__
+that has added some new features, including support for decoding
+barcode orientation. At the time of writing the project does not produce Windows DLLs.
+If you see `orientation=None` then your system has an older release of zbar.
+The ``zbar`` ``DLL``\ s that are included with the Windows Python wheels are
+an old build that does not support orientation.
+
 Quality field
 -------------
 From

pyzbar/pyzbar.py

@@ -17,10 +17,12 @@
 )
 
 __all__ = [
- 'decode', 'Point', 'Rect', 'Decoded', 'ZBarSymbol', 'EXTERNAL_DEPENDENCIES'
+ 'decode', 'Point', 'Rect', 'Decoded', 'ZBarSymbol', 'EXTERNAL_DEPENDENCIES', 'ORIENTATION_AVAILABLE'
 ]
 
 
+ORIENTATION_AVAILABLE = zbar_symbol_get_orientation is not None
+
 Decoded = namedtuple('Decoded', 'data type rect polygon quality orientation')
 
 # ZBar's magic 'fourcc' numbers that represent image formats
@@ -120,7 +122,12 @@ def _decode_symbols(symbols):
  )
  for index in _RANGEFN(zbar_symbol_get_loc_size(symbol))
  )
- orientation = ZBarOrientation(zbar_symbol_get_orientation(symbol)).name
+
+ if zbar_symbol_get_orientation:
+ orientation = ZBarOrientation(zbar_symbol_get_orientation(symbol)).name
+ else:
+ orientation = None
+
  yield Decoded(
  data=data,
  type=symbol_type,

pyzbar/tests/test_pyzbar.py

@@ -25,7 +25,7 @@
 
 from pyzbar import wrapper
 from pyzbar.pyzbar import (
- decode, Decoded, Rect, ZBarSymbol, EXTERNAL_DEPENDENCIES
+ decode, Decoded, Rect, ZBarSymbol, EXTERNAL_DEPENDENCIES, ORIENTATION_AVAILABLE
 )
 from pyzbar.pyzbar_error import PyZbarError
 
@@ -40,15 +40,15 @@ class TestDecode(unittest.TestCase):
  type='CODE128',
  rect=Rect(left=37, top=550, width=324, height=76),
  polygon=[(37, 551), (37, 625), (361, 626), (361, 550)],
- orientation='UP',
+ orientation='UP' if ORIENTATION_AVAILABLE else None,
  quality=77,
  ),
  Decoded(
  data=b'Rana temporaria',
  type='CODE128',
  rect=Rect(left=4, top=0, width=390, height=76),
  polygon=[(4, 1), (4, 75), (394, 76), (394, 0)],
- orientation='UP',
+ orientation='UP' if ORIENTATION_AVAILABLE else None,
  quality=77,
  ),
  ]
@@ -59,7 +59,7 @@ class TestDecode(unittest.TestCase):
  type='CODE128',
  rect=Rect(left=4, top=0, width=390, height=75),
  polygon=[(4, 1), (4, 75), (394, 74), (394, 0)],
- orientation="UP",
+ orientation="UP" if ORIENTATION_AVAILABLE else None,
  quality=76,
  ),
  ]
@@ -70,7 +70,7 @@ class TestDecode(unittest.TestCase):
  type='QRCODE',
  rect=Rect(left=27, top=27, width=145, height=145),
  polygon=[(27, 27), (27, 172), (172, 172), (172, 27)],
- orientation='UP',
+ orientation='UP' if ORIENTATION_AVAILABLE else None,
  quality=1,
  ),
  ]
@@ -82,15 +82,15 @@ class TestDecode(unittest.TestCase):
  type='QRCODE',
  rect=Rect(left=173, top=10, width=205, height=205),
  polygon=[(173, 113), (276, 215), (378, 113), (276, 10)],
- orientation='UP',
+ orientation='UP' if ORIENTATION_AVAILABLE else None,
  quality=1,
  ),
  Decoded(
  data=b'Thalassiodracon',
  type='QRCODE',
  rect=Rect(left=32, top=208, width=158, height=158),
  polygon=[(32, 352), (177, 366), (190, 222), (46, 208)],
- orientation='RIGHT',
+ orientation='RIGHT' if ORIENTATION_AVAILABLE else None,
  quality=1,
  ),
  ]

pyzbar/wrapper.py

@@ -270,11 +270,17 @@ def zbar_function(fname, restype, *args):
  c_uint
 )
 
-zbar_symbol_get_orientation = zbar_function(
- 'zbar_symbol_get_orientation',
- c_uint,
- POINTER(zbar_symbol)
-)
+
+try:
+ zbar_symbol_get_orientation = zbar_function(
+ 'zbar_symbol_get_orientation',
+ c_uint,
+ POINTER(zbar_symbol)
+ )
+except AttributeError:
+ # This function not present in the original pre-20
+ zbar_symbol_get_orientation = None
+
 
 zbar_symbol_next = zbar_function(
  'zbar_symbol_next',