A standard EAN-13 barcode visualization commonly used for retail products worldwide. The plot renders a scannable linear barcode encoding a 13-digit number with proper bar widths, guard patterns, and human-readable digits. This visualization is essential for product identification, inventory management, and point-of-sale systems.
""" anyplot.ai
barcode-ean13: EAN-13 Barcode
Library: altair 6.1.0 | Python 3.13.13
Quality: 87/100 | Updated: 2026-05-21
"""
import os
import sys
# Remove this script's directory from sys.path to prevent self-import
# (Python adds the script dir to sys.path[0], which would shadow the altair package)
_d = os.path.dirname(os.path.abspath(__file__))
sys.path = [p for p in sys.path if os.path.abspath(p or ".") != _d]
del _d
import altair as alt
import pandas as pd
from PIL import Image
# Theme tokens
THEME = os.getenv("ANYPLOT_THEME", "light")
PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
ELEVATED_BG = "#FFFDF6" if THEME == "light" else "#242420"
INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
# EAN-13 encoding patterns (7 modules per digit)
# L-codes (left side, odd parity): space, bar, space, bar
L_CODES = {
"0": [3, 2, 1, 1],
"1": [2, 2, 2, 1],
"2": [2, 1, 2, 2],
"3": [1, 4, 1, 1],
"4": [1, 1, 3, 2],
"5": [1, 2, 3, 1],
"6": [1, 1, 1, 4],
"7": [1, 3, 1, 2],
"8": [1, 2, 1, 3],
"9": [3, 1, 1, 2],
}
# G-codes (left side, even parity): space, bar, space, bar
G_CODES = {
"0": [1, 1, 2, 3],
"1": [1, 2, 2, 2],
"2": [2, 2, 1, 2],
"3": [1, 1, 4, 1],
"4": [2, 3, 1, 1],
"5": [1, 3, 2, 1],
"6": [4, 1, 1, 1],
"7": [2, 1, 3, 1],
"8": [3, 1, 2, 1],
"9": [2, 1, 1, 3],
}
# R-codes (right side): bar, space, bar, space
R_CODES = {
"0": [3, 2, 1, 1],
"1": [2, 2, 2, 1],
"2": [2, 1, 2, 2],
"3": [1, 4, 1, 1],
"4": [1, 1, 3, 2],
"5": [1, 2, 3, 1],
"6": [1, 1, 1, 4],
"7": [1, 3, 1, 2],
"8": [1, 2, 1, 3],
"9": [3, 1, 1, 2],
}
# First digit determines L/G pattern for left 6 digits
FIRST_DIGIT_PATTERNS = {
"0": "LLLLLL",
"1": "LLGLGG",
"2": "LLGGLG",
"3": "LLGGGL",
"4": "LGLLGG",
"5": "LGGLLG",
"6": "LGGGLL",
"7": "LGLGLG",
"8": "LGLGGL",
"9": "LGGLGL",
}
# Data - German product EAN-13 code
code = "4006381333931"
# Inline check digit calculation (no function)
if len(code) == 12:
_total = sum(int(d) * (1 if i % 2 == 0 else 3) for i, d in enumerate(code))
code = code + str((10 - (_total % 10)) % 10)
first_digit = code[0]
left_digits = code[1:7]
right_digits = code[7:13]
# Build barcode bar data
bars_data = []
quiet_zone = 9
x_pos = quiet_zone
# Start guard: 101 (bar, space, bar)
for i, width in enumerate([1, 1, 1]):
if i % 2 == 0:
bars_data.append({"x": x_pos, "x2": x_pos + width, "y": 0, "y2": 1.1})
x_pos += width
# Left 6 digits using L or G codes per first-digit pattern
encoding_pattern = FIRST_DIGIT_PATTERNS[first_digit]
is_bar = False
for i, digit in enumerate(left_digits):
widths = L_CODES[digit] if encoding_pattern[i] == "L" else G_CODES[digit]
for width in widths:
if is_bar:
bars_data.append({"x": x_pos, "x2": x_pos + width, "y": 0, "y2": 1.0})
x_pos += width
is_bar = not is_bar
# Center guard: 01010 (space, bar, space, bar, space)
for i, width in enumerate([1, 1, 1, 1, 1]):
if i % 2 == 1:
bars_data.append({"x": x_pos, "x2": x_pos + width, "y": 0, "y2": 1.1})
x_pos += width
# Right 6 digits using R codes
is_bar = True
for digit in right_digits:
for width in R_CODES[digit]:
if is_bar:
bars_data.append({"x": x_pos, "x2": x_pos + width, "y": 0, "y2": 1.0})
x_pos += width
is_bar = not is_bar
# End guard: 101 (bar, space, bar)
for i, width in enumerate([1, 1, 1]):
if i % 2 == 0:
bars_data.append({"x": x_pos, "x2": x_pos + width, "y": 0, "y2": 1.1})
x_pos += width
total_width = x_pos + quiet_zone
df_bars = pd.DataFrame(bars_data)
# Human-readable digit labels positioned below barcode
text_data = [
{"x": quiet_zone - 3, "y": -0.12, "text": first_digit},
{"x": quiet_zone + 3 + 21, "y": -0.12, "text": left_digits},
{"x": quiet_zone + 3 + 42 + 5 + 21, "y": -0.12, "text": right_digits},
]
df_text = pd.DataFrame(text_data)
# Structural zone annotations above barcode (EAN-13 anatomy)
# Left group (x=12–54): country prefix + manufacturer; Right group (x=59–101): product + check
zone_data = [
{"x": 33, "y": 1.20, "text": f"Country · Mfr ({left_digits})"},
{"x": 80, "y": 1.20, "text": f"Product · Check ({right_digits})"},
]
df_zones = pd.DataFrame(zone_data)
# Barcode bars chart
bars_chart = (
alt.Chart(df_bars)
.mark_rect(color=INK)
.encode(
x=alt.X("x:Q", scale=alt.Scale(domain=[0, total_width]), axis=None),
x2="x2:Q",
y=alt.Y("y:Q", scale=alt.Scale(domain=[-0.25, 1.38]), axis=None),
y2="y2:Q",
)
)
# Digit labels below barcode
text_chart = (
alt.Chart(df_text)
.mark_text(fontSize=18, font="monospace", fontWeight="bold", color=INK)
.encode(x="x:Q", y="y:Q", text="text:N")
)
# Zone annotation labels above barcode
zone_chart = (
alt.Chart(df_zones).mark_text(fontSize=12, font="monospace", color=INK_SOFT).encode(x="x:Q", y="y:Q", text="text:N")
)
# Combined chart with canonical landscape canvas
TITLE = "barcode-ean13 · python · altair · anyplot.ai"
chart = (
(bars_chart + text_chart + zone_chart)
.properties(
width=620,
height=320,
background=PAGE_BG,
title=alt.Title(TITLE, fontSize=16, anchor="middle", offset=20, color=INK),
)
.configure_view(fill=PAGE_BG, strokeWidth=0)
.configure_title(color=INK)
)
# Save PNG with padding to exact 3200×1800
chart.save(f"plot-{THEME}.png", scale_factor=4.0)
TW, TH = 3200, 1800
_img = Image.open(f"plot-{THEME}.png").convert("RGB")
_w, _h = _img.size
if _w > TW or _h > TH:
raise SystemExit(
f"altair vl-convert produced {_w}×{_h}, exceeds target {TW}×{TH}. "
f"Shrink chart .properties(width=, height=) values and re-render."
)
if _w < TW or _h < TH:
_canvas = Image.new("RGB", (TW, TH), PAGE_BG)
_canvas.paste(_img, ((TW - _w) // 2, (TH - _h) // 2))
_canvas.save(f"plot-{THEME}.png")
chart.save(f"plot-{THEME}.html")
Part of EAN-13 Barcode on anyplot.ai.