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: plotnine 0.15.4 | Python 3.13.13
Quality: 86/100 | Created: 2026-05-21
"""
import os
import sys
# Prevent this script from shadowing the installed 'plotnine' package
_here = os.path.dirname(os.path.abspath(__file__))
sys.path = [p for p in sys.path if not (p and os.path.abspath(p) == _here)]
os.chdir(_here)
import pandas as pd
from plotnine import (
aes,
annotate,
element_rect,
element_text,
geom_rect,
ggplot,
labs,
scale_x_continuous,
scale_y_continuous,
theme,
theme_void,
)
THEME = os.getenv("ANYPLOT_THEME", "light")
PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
ACCENT = "#009E73" # Okabe-Ito green for label header accent
# Code 128 Subset B patterns (binary: 1=bar, 0=space), 11 modules each, symbols 0-102
CODE128 = [
"11011001100",
"11001101100",
"11001100110",
"10010011000",
"10010001100",
"10001001100",
"10011001000",
"10011000100",
"10001100100",
"11001001000",
"11001000100",
"11000100100",
"10110011100",
"10011011100",
"10011001110",
"10111001100",
"10011101100",
"10011100110",
"11001110010",
"11001011100",
"11001001110",
"11011100100",
"11001110100",
"11101101110",
"11101001100",
"11100101100",
"11100100110",
"11101100100",
"11100110100",
"11100110010",
"11011011000",
"11011000110",
"11000110110",
"10100011000",
"10001011000",
"10001000110",
"10110001000",
"10001101000",
"10001100010",
"11010001000",
"11000101000",
"11000100010",
"10110111000",
"10110001110",
"10001101110",
"10111011000",
"10111000110",
"10001110110",
"11101110110",
"11010001110",
"11000101110",
"11011101000",
"11011100010",
"11011101110",
"11101011000",
"11101000110",
"11100010110",
"11101101000",
"11101100010",
"11100011010",
"11101111010",
"11001000010",
"11110001010",
"10100110000",
"10100001100",
"10010110000",
"10010000110",
"10000101100",
"10000100110",
"10110010000",
"10110000100",
"10011010000",
"10011000010",
"10000110100",
"10000110010",
"11000010010",
"11001010000",
"11110111010",
"11000010100",
"10001111010",
"10100111100",
"10010111100",
"10010011110",
"10111100100",
"10011110100",
"10011110010",
"11110100100",
"11110010100",
"11110010010",
"11011011110",
"11011110110",
"11110110110",
"10101111000",
"10100011110",
"10001011110",
"10111101000",
"10111100010",
"11110101000",
"11110100010",
"10111011110",
"10111101110",
"11101011110",
"11110101110",
]
START_B = "11010010000"
STOP = "1100011101011"
# Encode specimen label using Code 128 Subset B (ASCII 32-127, symbol = ASCII - 32)
text = "SPECIMEN-2024-B047"
symbol_vals = [ord(c) - 32 for c in text]
check = 104 # Start B value
for i, v in enumerate(symbol_vals):
check += (i + 1) * v
check %= 103
binary = START_B + "".join(CODE128[v] for v in symbol_vals) + CODE128[check] + STOP
# Convert binary string to bar segments (group consecutive 1-runs)
QUIET = 10
BAR_Y1, BAR_Y2 = 0.31, 0.79
bar_rows = []
i = 0
x = QUIET
while i < len(binary):
bit = binary[i]
j = i + 1
while j < len(binary) and binary[j] == bit:
j += 1
run = j - i
if bit == "1":
bar_rows.append({"xmin": float(x), "xmax": float(x + run), "ymin": BAR_Y1, "ymax": BAR_Y2})
x += run
i = j
total_w = float(x + QUIET)
df_bars = pd.DataFrame(bar_rows)
LABEL_X1 = 2.0
LABEL_X2 = total_w - 2.0
LABEL_MID = total_w / 2
# White label card (barcode always black-on-white for scan reliability)
df_label = pd.DataFrame({"xmin": [LABEL_X1], "xmax": [LABEL_X2], "ymin": [0.05], "ymax": [0.95]})
# Accent header strip for visual hierarchy
df_header = pd.DataFrame({"xmin": [LABEL_X1], "xmax": [LABEL_X2], "ymin": [0.81], "ymax": [0.95]})
plot = (
ggplot()
+ geom_rect(
data=df_label, mapping=aes(xmin="xmin", xmax="xmax", ymin="ymin", ymax="ymax"), fill="#FFFFFF", colour="none"
)
+ geom_rect(
data=df_header, mapping=aes(xmin="xmin", xmax="xmax", ymin="ymin", ymax="ymax"), fill=ACCENT, colour="none"
)
+ annotate("text", x=LABEL_MID, y=0.875, label="CODE 128 · SUBSET B", colour="#FFFFFF", size=7, family="monospace")
+ annotate("segment", x=LABEL_X1, xend=LABEL_X2, y=0.81, yend=0.81, colour=INK_SOFT, size=0.4)
+ geom_rect(
data=df_bars, mapping=aes(xmin="xmin", xmax="xmax", ymin="ymin", ymax="ymax"), fill="#1A1A17", colour="none"
)
+ annotate("text", x=LABEL_MID, y=0.20, label=text, colour="#1A1A17", size=9, family="monospace")
+ annotate(
"text",
x=LABEL_MID,
y=0.10,
label="Code 128B · 18 characters · Mod-103 check digit",
colour=INK_SOFT,
size=6,
family="monospace",
)
+ scale_x_continuous(limits=(0, total_w), expand=(0, 0))
+ scale_y_continuous(limits=(0, 1), expand=(0, 0))
+ labs(title="Specimen Label · barcode-code128 · python · plotnine · anyplot.ai")
+ theme_void()
+ theme(
figure_size=(8, 4.5),
plot_background=element_rect(fill=PAGE_BG, colour=PAGE_BG),
plot_title=element_text(colour=INK, size=12, hjust=0.5),
)
)
plot.save(f"plot-{THEME}.png", dpi=400, width=8, height=4.5, units="in")
Part of Code 128 Barcode on anyplot.ai.