A Code 128 barcode visualization that encodes alphanumeric data into a high-density linear barcode pattern. Code 128 is a widely-used 1D barcode format that supports the full 128 ASCII character set, with three code subsets (A, B, C) that can be switched dynamically for optimal encoding efficiency. This visualization generates scannable barcodes commonly found on shipping labels, industrial parts, and healthcare specimens.
""" anyplot.ai
barcode-code128: Code 128 Barcode
Library: seaborn 0.13.2 | Python 3.13.13
Quality: 84/100 | Updated: 2026-05-21
"""
import os
import matplotlib.pyplot as plt
import numpy as np
import seaborn as sns
# 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"
INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
sns.set_theme(
style="white",
rc={"figure.facecolor": PAGE_BG, "axes.facecolor": PAGE_BG, "axes.edgecolor": INK_SOFT, "text.color": INK},
)
# Code 128 encoding tables (subset B — full printable ASCII)
CODE128_B_PATTERNS = {
" ": "11011001100",
"!": "11001101100",
'"': "11001100110",
"#": "10010011000",
"$": "10010001100",
"%": "10001001100",
"&": "10011001000",
"'": "10011000100",
"(": "10001100100",
")": "11001001000",
"*": "11001000100",
"+": "11000100100",
",": "10110011100",
"-": "10011011100",
".": "10011001110",
"/": "10111001100",
"0": "10011101100",
"1": "10011100110",
"2": "11001110010",
"3": "11001011100",
"4": "11001001110",
"5": "11011100100",
"6": "11001110100",
"7": "11101101110",
"8": "11101001100",
"9": "11100101100",
":": "11100100110",
";": "11101100100",
"<": "11100110100",
"=": "11100110010",
">": "11011011000",
"?": "11011000110",
"@": "11000110110",
"A": "10100011000",
"B": "10001011000",
"C": "10001000110",
"D": "10110001000",
"E": "10001101000",
"F": "10001100010",
"G": "11010001000",
"H": "11000101000",
"I": "11000100010",
"J": "10110111000",
"K": "10110001110",
"L": "10001101110",
"M": "10111011000",
"N": "10111000110",
"O": "10001110110",
"P": "11101110110",
"Q": "11010001110",
"R": "11000101110",
"S": "11011101000",
"T": "11011100010",
"U": "11011101110",
"V": "11101011000",
"W": "11101000110",
"X": "11100010110",
"Y": "11101101000",
"Z": "11101100010",
"[": "11100011010",
"\\": "11101111010",
"]": "11001000010",
"^": "11110001010",
"_": "10100110000",
"`": "10100001100",
"a": "10010110000",
"b": "10010000110",
"c": "10000101100",
"d": "10000100110",
"e": "10110010000",
"f": "10110000100",
"g": "10011010000",
"h": "10011000010",
"i": "10000110100",
"j": "10000110010",
"k": "11000010010",
"l": "11001010000",
"m": "11110111010",
"n": "11000010100",
"o": "10001111010",
"p": "10100111100",
"q": "10010111100",
"r": "10010011110",
"s": "10111100100",
"t": "10011110100",
"u": "10011110010",
"v": "11110100100",
"w": "11110010100",
"x": "11110010010",
"y": "11011011110",
"z": "11011110110",
"{": "11110110110",
"|": "10101111000",
"}": "10100011110",
"~": "10001011110",
}
CODE128_VALUES = {
" ": 0,
"!": 1,
'"': 2,
"#": 3,
"$": 4,
"%": 5,
"&": 6,
"'": 7,
"(": 8,
")": 9,
"*": 10,
"+": 11,
",": 12,
"-": 13,
".": 14,
"/": 15,
"0": 16,
"1": 17,
"2": 18,
"3": 19,
"4": 20,
"5": 21,
"6": 22,
"7": 23,
"8": 24,
"9": 25,
":": 26,
";": 27,
"<": 28,
"=": 29,
">": 30,
"?": 31,
"@": 32,
"A": 33,
"B": 34,
"C": 35,
"D": 36,
"E": 37,
"F": 38,
"G": 39,
"H": 40,
"I": 41,
"J": 42,
"K": 43,
"L": 44,
"M": 45,
"N": 46,
"O": 47,
"P": 48,
"Q": 49,
"R": 50,
"S": 51,
"T": 52,
"U": 53,
"V": 54,
"W": 55,
"X": 56,
"Y": 57,
"Z": 58,
"[": 59,
"\\": 60,
"]": 61,
"^": 62,
"_": 63,
"`": 64,
"a": 65,
"b": 66,
"c": 67,
"d": 68,
"e": 69,
"f": 70,
"g": 71,
"h": 72,
"i": 73,
"j": 74,
"k": 75,
"l": 76,
"m": 77,
"n": 78,
"o": 79,
"p": 80,
"q": 81,
"r": 82,
"s": 83,
"t": 84,
"u": 85,
"v": 86,
"w": 87,
"x": 88,
"y": 89,
"z": 90,
"{": 91,
"|": 92,
"}": 93,
"~": 94,
}
# Patterns for check digit values 95–105 (no ASCII mapping)
CHECK_PATTERNS = [
"11110101000",
"11110100010",
"10111011110",
"10111101110",
"10111110110",
"11101011110",
"11110101110",
"11010000100",
"11010010000",
"11010011100",
"11000111010",
]
START_B = "11010010000"
STOP = "1100011101011"
QUIET = "0" * 10
# Data
content = "SHIP-2024-ABC123"
# Encode using Code 128 subset B with modulo-103 check digit
barcode_binary = START_B
checksum = 104
for i, char in enumerate(content):
barcode_binary += CODE128_B_PATTERNS[char]
checksum += CODE128_VALUES[char] * (i + 1)
check_value = checksum % 103
if check_value < 95:
for char, val in CODE128_VALUES.items():
if val == check_value:
barcode_binary += CODE128_B_PATTERNS[char]
break
else:
barcode_binary += CHECK_PATTERNS[check_value - 95]
barcode_binary += STOP
barcode_with_quiet = QUIET + barcode_binary + QUIET
# Zone boundary positions (column indices)
n_cols = len(barcode_with_quiet)
q = len(QUIET) # 10
s = len(START_B) # 11
d = len(content) * 11 # 176
ck = 11 # check digit symbol
st = len(STOP) # 13
zone_defs = [
(0, q, INK_SOFT, 0.20, ""),
(q, q + s, "#009E73", 0.85, "Start\n128B"),
(q + s, q + s + d, "#4467A3", 0.80, f"Data region · {len(content)} chars"),
(q + s + d, q + s + d + ck, "#C475FD", 0.85, "Check\nmod 103"),
(q + s + d + ck, q + s + d + ck + st, "#BD8233", 0.85, "Stop"),
(n_cols - q, n_cols, INK_SOFT, 0.20, ""),
]
# Build 2D barcode matrix
barcode_array = np.array([[int(bit) for bit in barcode_with_quiet]])
barcode_data = np.repeat(barcode_array, 40, axis=0)
# Seaborn-native two-color blend palette as colormap
cmap = sns.blend_palette([PAGE_BG, INK], n_colors=256, as_cmap=True)
# Layout: barcode panel + zone annotation strip
fig, (ax, ax_ann) = plt.subplots(
2, 1, figsize=(8, 4.5), dpi=400, facecolor=PAGE_BG, gridspec_kw={"height_ratios": [6, 1], "hspace": 0.03}
)
# Barcode panel
sns.heatmap(barcode_data, cmap=cmap, cbar=False, xticklabels=False, yticklabels=False, linewidths=0, ax=ax)
sns.despine(ax=ax, left=True, bottom=True, top=True, right=True)
ax.set_title("barcode-code128 · python · seaborn · anyplot.ai", fontsize=12, fontweight="medium", color=INK, pad=10)
# Zone annotation strip — structural callouts for each barcode section
ax_ann.set_facecolor(ELEVATED_BG)
ax_ann.set_xlim(0, n_cols)
ax_ann.set_ylim(0, 1)
for x0, x1, color, alpha, label in zone_defs:
width = x1 - x0
ax_ann.add_patch(plt.Rectangle((x0, 0), width, 1, color=color, alpha=alpha))
if label and width > 12:
ax_ann.text(
(x0 + x1) / 2,
0.5,
label,
ha="center",
va="center",
fontsize=5.5,
color="white",
fontweight="bold",
linespacing=1.3,
)
sns.despine(ax=ax_ann, left=True, bottom=True, top=True, right=True)
ax_ann.set_xticks([])
ax_ann.set_yticks([])
fig.subplots_adjust(top=0.88, bottom=0.11, left=0.02, right=0.98)
fig.text(
0.5, 0.04, content, ha="center", va="center", fontsize=10, fontfamily="monospace", fontweight="bold", color=INK
)
# Save
plt.savefig(f"plot-{THEME}.png", dpi=400, facecolor=PAGE_BG)
Part of Code 128 Barcode on anyplot.ai.