A swarm plot (beeswarm plot) displays individual data points for categorical comparisons, with points spread horizontally to avoid overlap. This reveals the full distribution shape and density while preserving exact values - combining the benefits of strip plots (individual points) and violin plots (density visualization). Ideal when you need to see every observation rather than just summary statistics.
# anyplot.ai
# swarm-basic: Basic Swarm Plot
# Library: makie 0.21.9 | Julia 1.11.9
# Quality: 91/100 | Created: 2026-07-26
using CairoMakie
using Colors
using Random
using Statistics
Random.seed!(42)
# --- Theme tokens (see prompts/default-style-guide.md "Theme-adaptive Chrome") ----
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"
# Imprint categorical palette — first 4 positions used, one per department
const IMPRINT_PALETTE = [
colorant"#009E73", # 1 — brand green (always first series)
colorant"#C475FD", # 2 — lavender
colorant"#4467A3", # 3 — blue
colorant"#BD8233", # 4 — ochre
]
# --- Data ---------------------------------------------------------------------
# Employee performance scores by department
departments = ["Engineering", "Sales", "Support", "Marketing"]
group_sizes = [45, 52, 38, 47]
group_means = [78.0, 71.0, 82.0, 75.0]
group_stds = [7.0, 11.0, 5.5, 9.0]
# Swarm layout: greedy nearest-free-slot placement so points spread
# horizontally (category axis) without overlapping, while keeping the
# true value on the vertical axis. Rectangular collision check (separate
# x/y thresholds) since the two axes carry different units.
min_dist_y = 1.1 # vertical threshold below which points compete for space (score points)
step_x = 0.055 # horizontal offset increment (category-axis units)
swarm_x = Float64[]
swarm_y = Float64[]
swarm_color = eltype(IMPRINT_PALETTE)[]
group_medians = Float64[]
max_offset = 0.0
for (group_index, (department, n, group_mean, group_std)) in
enumerate(zip(departments, group_sizes, group_means, group_stds))
scores = clamp.(randn(n) .* group_std .+ group_mean, 0.0, 100.0)
order = sortperm(scores)
placed_offsets = Float64[]
placed_scores = Float64[]
offsets = zeros(n)
for i in order
score = scores[i]
level = 0
chosen_offset = 0.0
while true
candidates = level == 0 ? (0.0,) : (level * step_x, -level * step_x)
free_slot = 0.0
found = false
for candidate in candidates
conflict = false
for j in eachindex(placed_scores)
if abs(placed_scores[j] - score) < min_dist_y &&
abs(placed_offsets[j] - candidate) < step_x
conflict = true
break
end
end
if !conflict
free_slot = candidate
found = true
break
end
end
if found
chosen_offset = free_slot
break
end
level += 1
end
offsets[i] = chosen_offset
push!(placed_offsets, chosen_offset)
push!(placed_scores, score)
end
append!(swarm_x, group_index .+ offsets)
append!(swarm_y, scores)
append!(swarm_color, fill(IMPRINT_PALETTE[group_index], n))
push!(group_medians, median(scores))
global max_offset = max(max_offset, maximum(abs, offsets))
end
# Headline comparison for the subtitle + callout: the department with the
# highest median score drives the data story beyond the per-group medians.
best_idx = argmax(group_medians)
subtitle_text = "$(departments[best_idx]) leads with the highest median score " *
"($(round(Int, group_medians[best_idx])))"
# --- Plot -----------------------------------------------------------------------
fig = Figure(
resolution = (1600, 900),
fontsize = 14,
backgroundcolor = PAGE_BG,
)
ax = Axis(
fig[1, 1];
title = "swarm-basic · julia · makie · anyplot.ai",
titlesize = 20,
titlecolor = INK,
subtitle = subtitle_text,
subtitlesize = 14,
subtitlecolor = INK_SOFT,
xlabel = "Department",
ylabel = "Performance Score (0–100)",
xlabelsize = 16,
ylabelsize = 16,
xlabelcolor = INK,
ylabelcolor = INK,
xticklabelsize = 13,
yticklabelsize = 13,
xticklabelcolor = INK_SOFT,
yticklabelcolor = INK_SOFT,
xtickcolor = INK_SOFT,
ytickcolor = INK_SOFT,
backgroundcolor = PAGE_BG,
topspinevisible = false,
rightspinevisible = false,
leftspinecolor = INK_SOFT,
bottomspinecolor = INK_SOFT,
xgridvisible = false,
ygridcolor = RGBAf(INK.r, INK.g, INK.b, 0.15),
yminorgridvisible = false,
xticks = (1:length(departments), departments),
)
scatter!(ax, swarm_x, swarm_y;
color = swarm_color, markersize = 11,
strokewidth = 0.75, strokecolor = INK)
# Median marker per department; the top performer gets a bolder line so the
# subtitle's callout has a visible anchor on the chart.
for (group_index, group_median) in enumerate(group_medians)
lines!(ax, [group_index - 0.32, group_index + 0.32], [group_median, group_median];
color = INK, linewidth = group_index == best_idx ? 3.5 : 2.5)
end
# Symmetric padding derived from the widest swarm actually placed, so the
# canvas margins stay balanced regardless of how far any one department spreads.
pad = max_offset + 0.12
xlims!(ax, 1 - pad, length(departments) + pad)
# --- Save -------------------------------------------------------------------
save("plot-$(THEME).png", fig; px_per_unit = 2)
Part of Basic Swarm Plot on anyplot.ai.