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: makie 0.21.9 | Julia 1.11.9
# Quality: 92/100 | Created: 2026-09-01
using CairoMakie
using Colors
# --- Theme tokens ------------------------------------------------------------
const THEME = get(ENV, "ANYPLOT_THEME", "light")
const PAGE_BG = THEME == "light" ? colorant"#FAF8F1" : colorant"#1A1A17"
const INK = THEME == "light" ? colorant"#1A1A17" : colorant"#F0EFE8"
const INK_SOFT = THEME == "light" ? colorant"#4A4A44" : colorant"#B8B7B0"
const INK_MUTED = THEME == "light" ? colorant"#6B6A63" : colorant"#A8A79F"
# A printed barcode label is black ink on white stock under any lighting —
# it does not follow the page theme the way surrounding chrome does, so
# these two stay fixed instead of branching on THEME.
const LABEL_BG = colorant"#FFFFFF"
const BAR_INK = colorant"#0A0A0A"
const LABEL_INK = colorant"#1A1A17"
# Imprint brand accent — a data-palette color, so it stays fixed across themes.
const ACCENT = colorant"#009E73"
# --- Data: Code 128 Subset B encoding -----------------------------------------
# Laboratory specimen tracking label.
content = "SPEC-88451-QC"
# Subset B covers ASCII 32 (space) through 127 (DEL) as symbol values 0-95,
# i.e. symbol value = character code point - 32. This spans every printable
# character, so subset B alone can encode the full label without switching.
values = [Int(c) - 32 for c in content]
start_value = 104 # Start Code B
checksum = mod(start_value + sum(v * i for (i, v) in enumerate(values)), 103)
codewords = vcat([start_value], values, [checksum], [106]) # 106 = Stop
# Bar/space module-width patterns (ISO/IEC 15417) for symbol values 0-105 —
# 6 widths each, alternating bar/space starting with a bar. Index 106 is the
# unique 13-module Stop pattern (7 widths, also starting with a bar).
const CODE128_WIDTHS = [
[2,1,2,2,2,2], [2,2,2,1,2,2], [2,2,2,2,2,1], [1,2,1,2,2,3], [1,2,1,3,2,2],
[1,3,1,2,2,2], [1,2,2,2,1,3], [1,2,2,3,1,2], [1,3,2,2,1,2], [2,2,1,2,1,3],
[2,2,1,3,1,2], [2,3,1,2,1,2], [1,1,2,2,3,2], [1,2,2,1,3,2], [1,2,2,2,3,1],
[1,1,3,2,2,2], [1,2,3,1,2,2], [1,2,3,2,2,1], [2,2,3,2,1,1], [2,2,1,1,3,2],
[2,2,1,2,3,1], [2,1,3,2,1,2], [2,2,3,1,1,2], [3,1,2,1,3,1], [3,1,1,2,2,2],
[3,2,1,1,2,2], [3,2,1,2,2,1], [3,1,2,2,1,2], [3,2,2,1,1,2], [3,2,2,2,1,1],
[2,1,2,1,2,3], [2,1,2,3,2,1], [2,3,2,1,2,1], [1,1,1,3,2,3], [1,3,1,1,2,3],
[1,3,1,3,2,1], [1,1,2,3,1,3], [1,3,2,1,1,3], [1,3,2,3,1,1], [2,1,1,3,1,3],
[2,3,1,1,1,3], [2,3,1,3,1,1], [1,1,2,1,3,3], [1,1,2,3,3,1], [1,3,2,1,3,1],
[1,1,3,1,2,3], [1,1,3,3,2,1], [1,3,3,1,2,1], [3,1,3,1,2,1], [2,1,1,3,3,1],
[2,3,1,1,3,1], [2,1,3,1,1,3], [2,1,3,3,1,1], [2,1,3,1,3,1], [3,1,1,1,2,3],
[3,1,1,3,2,1], [3,3,1,1,2,1], [3,1,2,1,1,3], [3,1,2,3,1,1], [3,3,2,1,1,1],
[3,1,4,1,1,1], [2,2,1,4,1,1], [4,3,1,1,1,1], [1,1,1,2,2,4], [1,1,1,4,2,2],
[1,2,1,1,2,4], [1,2,1,4,2,1], [1,4,1,1,2,2], [1,4,1,2,2,1], [1,1,2,2,1,4],
[1,1,2,4,1,2], [1,2,2,1,1,4], [1,2,2,4,1,1], [1,4,2,1,1,2], [1,4,2,2,1,1],
[2,4,1,2,1,1], [2,2,1,1,1,4], [4,1,3,1,1,1], [2,4,1,1,1,2], [1,3,4,1,1,1],
[1,1,1,2,4,2], [1,2,1,1,4,2], [1,2,1,2,4,1], [1,1,4,2,1,2], [1,2,4,1,1,2],
[1,2,4,2,1,1], [4,1,1,2,1,2], [4,2,1,1,1,2], [4,2,1,2,1,1], [2,1,2,1,4,1],
[2,1,4,1,2,1], [4,1,2,1,2,1], [1,1,1,1,4,3], [1,1,1,3,4,1], [1,3,1,1,4,1],
[1,1,4,1,1,3], [1,1,4,3,1,1], [4,1,1,1,1,3], [4,1,1,3,1,1], [1,1,3,1,4,1],
[1,1,4,1,3,1], [3,1,1,1,4,1], [4,1,1,1,3,1], [2,1,1,4,1,2], [2,1,1,2,1,4],
[2,1,1,2,3,2],
[2,3,3,1,1,1,2],
]
# --- Geometry ------------------------------------------------------------------
module_width = 6 # design px per module
quiet_modules = 10 # ISO/IEC 15417 minimum quiet zone, each side
bar_widths = [CODE128_WIDTHS[c + 1] for c in codewords] # +1: Julia is 1-indexed
flat_widths = vcat(bar_widths...) .* module_width
is_bar = vcat([isodd.(1:length(w)) for w in bar_widths]...)
barcode_width = sum(flat_widths)
quiet_width = quiet_modules * module_width
half_block = barcode_width / 2 + quiet_width
canvas_center = 800.0
block_left = canvas_center - half_block
bar_x0 = block_left + quiet_width
edges = cumsum(vcat([0.0], flat_widths))
bar_starts = edges[1:end-1][is_bar] .+ bar_x0
bar_lengths = flat_widths[is_bar]
bar_y_bottom = 357.5
bar_height = 260.0
bar_rects = Rect2f.(bar_starts, bar_y_bottom, bar_lengths, bar_height)
card_pad_x = 60.0
card_x = block_left - card_pad_x
card_width = 2 * half_block + 2 * card_pad_x
card_y = 267.5
card_height = 400.0
# --- Plot ------------------------------------------------------------------
fig = Figure(size = (1600, 900), backgroundcolor = PAGE_BG)
ax = Axis(fig[1, 1]; backgroundcolor = PAGE_BG, aspect = DataAspect())
hidedecorations!(ax)
hidespines!(ax)
xlims!(ax, 0, 1600)
ylims!(ax, 0, 900)
poly!(ax, Rect2f(card_x, card_y, card_width, card_height); color = LABEL_BG)
poly!(ax, bar_rects; color = BAR_INK)
text!(ax, canvas_center, 782.5;
text = "barcode-code128 · julia · makie · anyplot.ai",
color = INK, fontsize = 30, align = (:center, :center))
text!(ax, canvas_center, 725.5;
text = "Laboratory specimen label",
color = INK_SOFT, fontsize = 18, align = (:center, :center))
# Brand accent between the subtitle and the card — a small polish touch
# that never touches the black-ink-on-white barcode itself.
poly!(ax, Rect2f(canvas_center - 55, 693.5, 110, 4); color = ACCENT)
text!(ax, canvas_center, 307.5; text = content,
color = LABEL_INK, fontsize = 26, font = :bold, align = (:center, :center))
text!(ax, canvas_center, 117.5;
text = "Code 128, Subset B · Quiet zone $(quiet_modules) modules each side · Check digit $(checksum)",
color = INK_MUTED, fontsize = 15, align = (:center, :center))
# --- Save ------------------------------------------------------------------
save("plot-$(THEME).png", fig; px_per_unit = 2)
Runnable source as JSON, for any HTTP client: https://api.anyplot.ai/specs/barcode-code128/makie/code. Any spec id and library id listed in llms-full.txt fit the same URL shape; every URL below is complete and callable.
{
"spec_id": "barcode-code128",
"language": "julia",
"library": "makie",
"page": "https://anyplot.ai/barcode-code128/julia/makie",
"hub": "https://anyplot.ai/barcode-code128",
"code_json": "https://api.anyplot.ai/specs/barcode-code128/makie/code",
"spec_json": "https://api.anyplot.ai/specs/barcode-code128",
"render_light_png": "https://storage.googleapis.com/anyplot-images/plots/barcode-code128/julia/makie/plot-light.png",
"render_dark_png": "https://storage.googleapis.com/anyplot-images/plots/barcode-code128/julia/makie/plot-dark.png",
"quality_score": 92.0,
"license": "MIT",
"guide": "https://anyplot.ai/llms.txt"
}Part of Code 128 Barcode on anyplot.ai.