initial commit

python/ean.py

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+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""
+This module can generate EAN-8 and EAN-13 barcodes
+
+(C) 2022 Louis Heredero  louis.heredero@edu.vs.ch
+"""
+
+import pygame
+
+A = [
+    0b0001101,
+    0b0011001,
+    0b0010011,
+    0b0111101,
+    0b0100011,
+    0b0110001,
+    0b0101111,
+    0b0111011,
+    0b0110111,
+    0b0001011
+]
+
+# XOR 0b1111111
+C = list(map(lambda a: a^127, A))
+
+# Reverse bit order
+B = list(map(lambda c: int(f"{c:07b}"[::-1], 2), C))
+
+ean13_patterns = [
+    "AAAAAA",
+    "AABABB",
+    "AABBAB",
+    "AABBBA",
+    "ABAABB",
+    "ABBAAB",
+    "ABBBAA",
+    "ABABAB",
+    "ABABBA",
+    "ABBABA"
+]
+
+def bin_list(n):
+    return list(map(int, f"{n:07b}"))
+
+def luhn(digits):
+    checksum = sum([
+        digits[-i-1]*(3-i%2*2)
+        for i in range(len(digits))
+    ])
+    ctrl_key = 10 - checksum%10
+    if ctrl_key == 10:
+        ctrl_key = 0
+
+    return ctrl_key
+
+def ean8(digits):
+    digits.append(luhn(digits))
+    elmts = []
+
+    elmts += [1,0,1] #delimiter
+    for digit in digits[:4]:
+        elmts += bin_list(A[digit])
+
+    elmts += [0,1,0,1,0] #middle delimiter
+    for digit in digits[4:]:
+        elmts += bin_list(C[digit])
+
+    elmts += [1,0,1] #delimiter
+    return elmts
+
+def ean13(digits):
+    pattern = ean13_patterns[digits[0]]
+    digits.append(luhn(digits))
+    elmts = []
+
+    elmts += [1,0,1] #delimiter
+    for d in range(1,7):
+        _ = A if pattern[d-1] == "A" else B
+        digit = digits[d]
+        elmts += bin_list(_[digit])
+
+    elmts += [0,1,0,1,0] #middle delimiter
+    for digit in digits[7:]:
+        elmts += bin_list(C[digit])
+
+    elmts += [1,0,1] #delimiter
+    return elmts
+
+def draw_barcode(barcode, win):
+    width = win.get_width()*0.8
+    height = win.get_height()*0.5
+    bar_w = width/len(barcode)
+    rnd_bar_w = round(bar_w)
+
+    win.fill((255,255,255))
+    x = win.get_width()*0.1
+    y = win.get_height()*0.25
+
+    for c in barcode:
+        if c:
+            pygame.draw.rect(win, (0,0,0), [x, y, rnd_bar_w, height])
+
+        x += bar_w
+
+if __name__ == "__main__":
+    import base
+    
+    b = base.Base(800, 500, "EAN-8 / EAN-13 barcode generator")
+    
+    #barcode = ean8([8,4,2,7,3,7,2])
+    barcode = ean13([9,7,8,2,9,4,0,6,2,1,0,5])
+    
+    draw_barcode(barcode, b.w)
+    
+    b.main()