Facilitates sub-classing and user customization by using self

  This allows changing the default_writer/default_writer_options for some
sub-classes of Barcode without affecting all of them.

Author: Fernando Governatore

barcode/base.py

@@ -93,7 +93,7 @@ def render(self, writer_options=None, text=None):
 
         :returns: Output of the writers render method.
         """
-        options = Barcode.default_writer_options.copy()
+        options = self.default_writer_options.copy()
         options.update(writer_options or {})
         if options["write_text"] or text is not None:
             if text is not None:

barcode/codex.py

@@ -45,7 +45,7 @@ def __init__(self, code: str, writer=None, add_checksum: bool = True):
         self.code = code.upper()
         if add_checksum:
             self.code += self.calculate_checksum()
-        self.writer = writer or Barcode.default_writer()
+        self.writer = writer or self.default_writer()
         check_code(self.code, self.name, code39.REF)
 
     def __str__(self):
@@ -133,7 +133,7 @@ class Code128(Barcode):
 
     def __init__(self, code, writer=None):
         self.code = code
-        self.writer = writer or Barcode.default_writer()
+        self.writer = writer or self.default_writer()
         self._charset = "B"
         self._buffer = ""
         check_code(self.code, self.name, code128.ALL)

barcode/ean.py

@@ -72,7 +72,7 @@ def __init__(self, ean, writer=None, no_checksum=False, guardbar=False):
         else:
             self.EDGE = _ean.EDGE
             self.MIDDLE = _ean.MIDDLE
-        self.writer = writer or Barcode.default_writer()
+        self.writer = writer or self.default_writer()
 
     def __str__(self):
         return self.ean

barcode/itf.py

@@ -36,7 +36,7 @@ def __init__(self, code, writer=None, narrow=2, wide=5):
         if len(code) % 2 != 0:
             code = "0" + code
         self.code = code
-        self.writer = writer or Barcode.default_writer()
+        self.writer = writer or self.default_writer()
         self.narrow = narrow
         self.wide = wide
 

barcode/upc.py

@@ -41,7 +41,7 @@ def __init__(self, upc, writer=None, make_ean=False):
             )
         self.upc = upc
         self.upc = "{}{}".format(upc, self.calculate_checksum())
-        self.writer = writer or Barcode.default_writer()
+        self.writer = writer or self.default_writer()
 
     def __str__(self):
         if self.ean: