Merge pull request #102 from Governa/extensibility

Extensibility

Author: Hugo Barrera

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):
@@ -71,7 +71,7 @@ def build(self):
     def render(self, writer_options=None, text=None):
         options = {"module_width": MIN_SIZE, "quiet_zone": MIN_QUIET_ZONE}
         options.update(writer_options or {})
-        return Barcode.render(self, options, text)
+        return super().render(options, text)
 
 
 class PZN7(Code39):
@@ -98,7 +98,7 @@ def __init__(self, pzn, writer=None):
             )
         self.pzn = pzn
         self.pzn = "{}{}".format(pzn, self.calculate_checksum())
-        Code39.__init__(self, "PZN-{}".format(self.pzn), writer, add_checksum=False)
+        super().__init__("PZN-{}".format(self.pzn), writer, add_checksum=False)
 
     def get_fullcode(self):
         return "PZN-{}".format(self.pzn)
@@ -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)
@@ -248,7 +248,7 @@ def build(self):
     def render(self, writer_options=None, text=None):
         options = {"module_width": MIN_SIZE, "quiet_zone": MIN_QUIET_ZONE}
         options.update(writer_options or {})
-        return Barcode.render(self, options, text)
+        return super().render(options, text)
 
 
 class Gs1_128(Code128):

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
@@ -125,7 +125,7 @@ def to_ascii(self):
     def render(self, writer_options=None, text=None):
         options = {"module_width": SIZES["SC2"]}
         options.update(writer_options or {})
-        return Barcode.render(self, options, text)
+        return super().render(options, text)
 
 
 class EuropeanArticleNumber13WithGuard(EuropeanArticleNumber13):
@@ -150,12 +150,12 @@ class JapanArticleNumber(EuropeanArticleNumber13):
 
     valid_country_codes = list(range(450, 460)) + list(range(490, 500))
 
-    def __init__(self, jan, writer=None):
-        if int(jan[:3]) not in JapanArticleNumber.valid_country_codes:
+    def __init__(self, jan, *args, **kwargs):
+        if int(jan[:3]) not in self.valid_country_codes:
             raise WrongCountryCodeError(
                 "Country code isn't between 450-460 or 490-500."
             )
-        EuropeanArticleNumber13.__init__(self, jan, writer)
+        super().__init__(jan, *args, **kwargs)
 
 
 class EuropeanArticleNumber8(EuropeanArticleNumber13):
@@ -172,9 +172,6 @@ class EuropeanArticleNumber8(EuropeanArticleNumber13):
 
     digits = 7
 
-    def __init__(self, ean, writer=None, guardbar=False):
-        EuropeanArticleNumber13.__init__(self, ean, writer, guardbar=guardbar)
-
     def build(self):
         """Builds the barcode pattern from `self.ean`.
 

barcode/isxn.py

@@ -48,7 +48,7 @@ def __init__(self, isbn, writer=None):
         if isbn[:3] == "979":
             if isbn[3:5] not in ("10", "11"):
                 raise BarcodeError("ISBN must start with 97910 or 97911.")
-        EuropeanArticleNumber13.__init__(self, isbn, writer)
+        super().__init__(isbn, writer)
 
 
 class InternationalStandardBookNumber10(InternationalStandardBookNumber13):
@@ -71,7 +71,7 @@ def __init__(self, isbn, writer=None):
         isbn = isbn[: self.digits]
         self.isbn10 = isbn
         self.isbn10 = "{}{}".format(isbn, self._calculate_checksum())
-        InternationalStandardBookNumber13.__init__(self, "978" + isbn, writer)
+        super().__init__("978" + isbn, writer)
 
     def _calculate_checksum(self):
         tmp = sum(x * int(y) for x, y in enumerate(self.isbn10[:9], start=1)) % 11
@@ -104,7 +104,7 @@ def __init__(self, issn, writer=None):
         issn = issn[: self.digits]
         self.issn = issn
         self.issn = "{}{}".format(issn, self._calculate_checksum())
-        EuropeanArticleNumber13.__init__(self, self.make_ean(), writer)
+        super().__init__(self.make_ean(), writer)
 
     def _calculate_checksum(self):
         tmp = (

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
 
@@ -73,4 +73,4 @@ def render(self, writer_options, text=None):
             "quiet_zone": MIN_QUIET_ZONE,
         }
         options.update(writer_options or {})
-        return Barcode.render(self, options, text)
+        return super().render(options, text)

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:
@@ -108,7 +108,7 @@ def to_ascii(self):
     def render(self, writer_options=None, text=None):
         options = {"module_width": 0.33}
         options.update(writer_options or {})
-        return Barcode.render(self, options, text)
+        return super().render(options, text)
 
 
 UPCA = UniversalProductCodeA

barcode/writer.py

@@ -98,6 +98,7 @@ def __init__(
         self.text_distance = 5
         self.text_line_distance = 1
         self.center_text = True
+        self.guard_height_factor = 1.1
 
     def calculate_size(self, modules_per_line, number_of_lines):
         """Calculates the size of the barcode in pixel.
@@ -163,39 +164,47 @@ def set_options(self, options):
             if hasattr(self, key):
                 setattr(self, key, val)
 
+    def packed(self, line):
+        """
+        Pack line to list give better gfx result, otherwise in can
+        result in aliasing gaps
+        '11010111' -> [2, -1, 1, -1, 3]
+
+        This method will yield a sequence of pairs (width, height_factor).
+
+        :parameters:
+            line: String
+                A string matching the writer spec
+                (only contain 0 or 1 or G).
+        """
+        line += " "
+        c = 1
+        for i in range(0, len(line) - 1):
+            if line[i] == line[i + 1]:
+                c += 1
+            else:
+                if line[i] == "1":
+                    yield (c, 1)
+                elif line[i] == "G":
+                    yield (c, self.guard_height_factor)
+                else:
+                    yield (-c, self.guard_height_factor)
+                c = 1
+
     def render(self, code):
         """Renders the barcode to whatever the inheriting writer provides,
         using the registered callbacks.
 
         :parameters:
             code : List
                 List of strings matching the writer spec
-                (only contain 0 or 1).
+                (only contain 0 or 1 or G).
         """
         if self._callbacks["initialize"] is not None:
             self._callbacks["initialize"](code)
         ypos = 1.0
         base_height = self.module_height
         for cc, line in enumerate(code):
-            """
-            Pack line to list give better gfx result, otherwise in can
-            result in aliasing gaps
-            '11010111' -> [2, -1, 1, -1, 3]
-            """
-            line += " "
-            c = 1
-            mlist = []
-            for i in range(0, len(line) - 1):
-                if line[i] == line[i + 1]:
-                    c += 1
-                else:
-                    if line[i] == "1":
-                        mlist.append((c, 1))
-                    elif line[i] == "G":
-                        mlist.append((c, 1.1))
-                    else:
-                        mlist.append((-c, 1.1))
-                    c = 1
             # Left quiet zone is x startposition
             xpos = self.quiet_zone
             bxs = xpos  # x start of barcode
@@ -206,10 +215,7 @@ def render(self, code):
                 # Flag that indicates if the previous mod was part of an guard block:
                 "was_guard": False,
             }
-            for mod in mlist:
-                height_factor = mod[1]
-                mod = mod[0]
-
+            for mod, height_factor in self.packed(line):
                 if mod < 1:
                     color = self.background
                 else: