Merge pull request #100 from Governa/feature/longer_guard_bar

Adds support for longer guard bar to EAN13 and EAN8

Fixes #11

Author: Hugo Barrera

barcode/__init__.py

@@ -13,8 +13,10 @@
 from barcode.codex import Gs1_128
 from barcode.codex import PZN
 from barcode.ean import EAN13
+from barcode.ean import EAN13_GUARD
 from barcode.ean import EAN14
 from barcode.ean import EAN8
+from barcode.ean import EAN8_GUARD
 from barcode.ean import JAN
 from barcode.errors import BarcodeNotFoundError
 from barcode.isxn import ISBN10
@@ -26,7 +28,9 @@
 
 __BARCODE_MAP = {
     "ean8": EAN8,
+    "ean8-guard": EAN8_GUARD,
     "ean13": EAN13,
+    "ean13-guard": EAN13_GUARD,
     "ean": EAN13,
     "gtin": EAN14,
     "ean14": EAN14,

barcode/ean.py

@@ -43,7 +43,7 @@ class EuropeanArticleNumber13(Barcode):
 
     digits = 12
 
-    def __init__(self, ean, writer=None, no_checksum=False):
+    def __init__(self, ean, writer=None, no_checksum=False, guardbar=False):
         ean = ean[: self.digits]
         if not ean.isdigit():
             raise IllegalCharacterError("EAN code can only contain numbers.")
@@ -64,12 +64,22 @@ def __init__(self, ean, writer=None, no_checksum=False):
             )
         else:
             self.ean = "{}{}".format(ean, self.calculate_checksum())
+
+        self.guardbar = guardbar
+        if guardbar:
+            self.EDGE = _ean.EDGE.replace("1", "G")
+            self.MIDDLE = _ean.MIDDLE.replace("1", "G")
+        else:
+            self.EDGE = _ean.EDGE
+            self.MIDDLE = _ean.MIDDLE
         self.writer = writer or Barcode.default_writer()
 
     def __str__(self):
         return self.ean
 
     def get_fullcode(self):
+        if self.guardbar:
+            return self.ean[0] + " " + self.ean[1:7] + " " + self.ean[7:] + " >"
         return self.ean
 
     def calculate_checksum(self):
@@ -92,14 +102,14 @@ def build(self):
         :returns: The pattern as string
         :rtype: String
         """
-        code = _ean.EDGE[:]
+        code = self.EDGE[:]
         pattern = _ean.LEFT_PATTERN[int(self.ean[0])]
         for i, number in enumerate(self.ean[1:7]):
             code += _ean.CODES[pattern[i]][int(number)]
-        code += _ean.MIDDLE
+        code += self.MIDDLE
         for number in self.ean[7:]:
             code += _ean.CODES["C"][int(number)]
-        code += _ean.EDGE
+        code += self.EDGE
         return [code]
 
     def to_ascii(self):
@@ -109,7 +119,7 @@ def to_ascii(self):
         """
         code = self.build()
         for i, line in enumerate(code):
-            code[i] = line.replace("1", "|").replace("0", " ")
+            code[i] = line.replace("G", "|").replace("1", "|").replace("0", " ")
         return "\n".join(code)
 
     def render(self, writer_options=None, text=None):
@@ -118,6 +128,14 @@ def render(self, writer_options=None, text=None):
         return Barcode.render(self, options, text)
 
 
+class EuropeanArticleNumber13WithGuard(EuropeanArticleNumber13):
+
+    name = "EAN-13 with guards"
+
+    def __init__(self, *args, guardbar=True, **kwargs):
+        return super().__init__(*args, guardbar=guardbar, **kwargs)
+
+
 class JapanArticleNumber(EuropeanArticleNumber13):
     """Initializes JAN barcode.
 
@@ -154,24 +172,37 @@ class EuropeanArticleNumber8(EuropeanArticleNumber13):
 
     digits = 7
 
-    def __init__(self, ean, writer=None):
-        EuropeanArticleNumber13.__init__(self, ean, writer)
+    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`.
 
         :returns: The pattern as string
         :rtype: String
         """
-        code = _ean.EDGE[:]
+        code = self.EDGE[:]
         for number in self.ean[:4]:
             code += _ean.CODES["A"][int(number)]
-        code += _ean.MIDDLE
+        code += self.MIDDLE
         for number in self.ean[4:]:
             code += _ean.CODES["C"][int(number)]
-        code += _ean.EDGE
+        code += self.EDGE
         return [code]
 
+    def get_fullcode(self):
+        if self.guardbar:
+            return "< " + self.ean[:4] + " " + self.ean[4:] + " >"
+        return self.ean
+
+
+class EuropeanArticleNumber8WithGuard(EuropeanArticleNumber8):
+
+    name = "EAN-8 with guards"
+
+    def __init__(self, *args, guardbar=True, **kwargs):
+        return super().__init__(*args, guardbar=guardbar, **kwargs)
+
 
 class EuropeanArticleNumber14(EuropeanArticleNumber13):
     """Represents an EAN-14 barcode. See EAN13's __init__ for details.
@@ -204,5 +235,7 @@ def sum_(x, y):
 # Shortcuts
 EAN14 = EuropeanArticleNumber14
 EAN13 = EuropeanArticleNumber13
+EAN13_GUARD = EuropeanArticleNumber13WithGuard
 EAN8 = EuropeanArticleNumber8
+EAN8_GUARD = EuropeanArticleNumber8WithGuard
 JAN = JapanArticleNumber

barcode/writer.py

@@ -175,6 +175,7 @@ def render(self, code):
         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
@@ -189,23 +190,51 @@ def render(self, code):
                     c += 1
                 else:
                     if line[i] == "1":
-                        mlist.append(c)
+                        mlist.append((c, 1))
+                    elif line[i] == "G":
+                        mlist.append((c, 1.1))
                     else:
-                        mlist.append(-c)
+                        mlist.append((-c, 1.1))
                     c = 1
             # Left quiet zone is x startposition
             xpos = self.quiet_zone
             bxs = xpos  # x start of barcode
+            text = {
+                "start": [],       # The x start of a guard
+                "end": [],         # The x end of a guard
+                "xpos": [],        # The x position where to write a text block
+                "was_guard": False # Flag that indicates if the previous mod
+                                   # was part of an guard block
+            }
             for mod in mlist:
+                height_factor = mod[1]
+                mod = mod[0]
+
                 if mod < 1:
                     color = self.background
                 else:
                     color = self.foreground
+
+                    if text["was_guard"] and height_factor == 1:
+                        # The current guard ended, store its x position
+                        text["end"].append(xpos)
+                        text["was_guard"] = False
+                    elif not text["was_guard"] and height_factor != 1:
+                        # A guard started, store its x position
+                        text["start"].append(xpos)
+                        text["was_guard"] = True
+
+                self.module_height = base_height * height_factor
                 # remove painting for background colored tiles?
                 self._callbacks["paint_module"](
                     xpos, ypos, self.module_width * abs(mod), color
                 )
                 xpos += self.module_width * abs(mod)
+            else:
+                if height_factor != 1:
+                    text["end"].append(xpos)
+                self.module_height = base_height
+
             bxe = xpos
             # Add right quiet zone to every line, except last line,
             # quiet zone already provided with background,
@@ -215,14 +244,41 @@ def render(self, code):
                     xpos, ypos, self.quiet_zone, self.background
                 )
             ypos += self.module_height
+
         if self.text and self._callbacks["paint_text"] is not None:
-            ypos += self.text_distance
-            if self.center_text:
-                # better center position for text
-                xpos = bxs + ((bxe - bxs) / 2.0)
+            if not text["start"]:
+                # If we don't have any start value, print the entire ean
+                ypos += self.text_distance
+                if self.center_text:
+                    # better center position for text
+                    xpos = bxs + ((bxe - bxs) / 2.0)
+                else:
+                    xpos = bxs
+                self._callbacks["paint_text"](xpos, ypos)
             else:
-                xpos = bxs
-            self._callbacks["paint_text"](xpos, ypos)
+                # Else, divide the ean into blocks and print each block
+                # in the expected position.
+                text["xpos"] = [bxs - 4 * self.module_width]
+
+                # Calculates the position of the text by getting the difference
+                # between a guard end and the next start
+                text["start"].pop(0)
+                for (s, e) in zip(text["start"], text["end"]):
+                    text["xpos"].append(e + (s - e) / 2)
+
+                # The last text block is always put after the last guard end
+                text["xpos"].append(text["end"][-1] + 4 * self.module_width)
+
+                # Split the ean into its blocks
+                self.text = self.text.split(" ")
+
+                ypos += pt2mm(self.font_size)
+
+                blocks = self.text
+                for (text, xpos) in zip(blocks, text["xpos"]):
+                    self.text = text
+                    self._callbacks["paint_text"](xpos, ypos)
+
         return self._callbacks["finish"]()
 
 

tests/test_builds.py

@@ -6,3 +6,10 @@ def test_ean8_builds():
     ean = get_barcode("ean8", "40267708")
     bc = ean.build()
     assert ref == bc[0]
+
+def test_ean8_builds_with_longer_bars():
+    ref = "G0G01000110001101001001101011110G0G01000100100010011100101001000G0G"
+    ean = get_barcode("ean8", "40267708", options={"guardbar": True})
+    bc = ean.build()
+    assert ref == bc[0]
+

tests/test_manually.py

@@ -32,7 +32,9 @@
 
 TESTCODES = (
     ("ean8", "40267708"),
+    ("ean8-guard", "40267708"),
     ("ean13", "5901234123457"),
+    ("ean13-guard", "5901234123457"),
     ("ean14", "12345678911230"),
     ("upca", "36000291453"),
     ("jan", "4901234567894"),

tests/test_writers.py

@@ -36,3 +36,11 @@ def test_saving_svg_to_byteio():
 
     with open(f"{TESTPATH}/somefile.svg", "wb") as f:
         EAN13("100000011111", writer=SVGWriter()).write(f)
+
+def test_saving_svg_to_byteio_with_guardbar():
+    rv = BytesIO()
+    EAN13(str(100000902922), writer=SVGWriter(), guardbar=True).write(rv)
+
+    with open(f"{TESTPATH}/somefile_guardbar.svg", "wb") as f:
+        EAN13("100000011111", writer=SVGWriter(), guardbar=True).write(f)
+