A nested donut chart displays hierarchical data as multiple concentric rings, where each ring represents a level of the hierarchy. Inner rings show parent categories while outer rings show their subdivisions. This visualization effectively reveals part-to-whole relationships across multiple levels while maintaining the familiar donut format.
""" anyplot.ai
donut-nested: Nested Donut Chart
Library: pygal 3.1.0 | Python 3.13.13
Quality: 81/100 | Updated: 2026-05-08
"""
import io
import os
import pygal
from PIL import Image
from pygal.style import Style
# Theme tokens (light/dark adaptive)
THEME = os.getenv("ANYPLOT_THEME", "light")
PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
INK_MUTED = "#6B6A63" if THEME == "light" else "#A8A79F"
BRAND = "#009E73" # Okabe-Ito position 1 (first series)
# Data: Market share by region (inner) and product lines within each region (outer)
# Using market share domain per spec's library independence requirement
data = {
"North America": {"Premium": 320, "Standard": 480, "Budget": 200},
"Europe": {"Premium": 280, "Standard": 420, "Budget": 150},
"Asia-Pacific": {"Premium": 450, "Standard": 590, "Budget": 320},
"LATAM": {"Premium": 140, "Standard": 210, "Budget": 90},
}
# Okabe-Ito color families: each region gets a base hue with lighter shades for product lines
# Position 1 (green) for first region, then positions 2-7 for others
oi_base_colors = (
"#009E73", # 1: bluish green
"#C475FD", # 2: vermillion
"#4467A3", # 3: blue
"#BD8233", # 4: reddish purple
)
color_families = {}
for i, region in enumerate(data.keys()):
base = oi_base_colors[i % len(oi_base_colors)]
# Generate lighter shades of the base color for child categories
if THEME == "light":
# Light versions for light theme
shades = [base, base + "CC", base + "99", base + "66"]
else:
# Slightly brighter for dark theme visibility
shades = [base, base + "DD", base + "BB", base + "99"]
color_families[region] = shades
# Prepare data for outer ring (product lines per region)
outer_labels = []
outer_colors = []
for region, products in data.items():
family = color_families[region]
for i, product_name in enumerate(products.keys()):
outer_labels.append(product_name)
outer_colors.append(family[min(i + 1, len(family) - 1)])
# Prepare data for inner ring (region totals)
inner_values = []
inner_labels = []
inner_colors = []
for region, products in data.items():
inner_values.append(sum(products.values()))
inner_labels.append(region)
inner_colors.append(color_families[region][0])
# Canvas size (square format for symmetric donut)
width = 3600
height = 3600
# Style for outer ring (product lines)
outer_style = Style(
background=PAGE_BG,
plot_background=PAGE_BG,
foreground=INK,
foreground_strong=INK,
foreground_subtle=INK_MUTED,
colors=tuple(outer_colors),
title_font_size=32,
label_font_size=20,
legend_font_size=18, # Increased from previous for better readability
value_font_size=16,
value_label_font_size=16,
)
# Style for inner ring (regions)
inner_style = Style(
background=PAGE_BG,
plot_background=PAGE_BG,
foreground=INK,
foreground_strong=INK,
foreground_subtle=INK_MUTED,
colors=tuple(inner_colors),
title_font_size=32,
label_font_size=22,
value_font_size=18,
value_label_font_size=18,
)
# Create outer ring (product lines per region)
# This renders as a transparent SVG that will be composited with the inner ring
outer_ring = pygal.Pie(
width=width,
height=height,
style=outer_style,
inner_radius=0.55,
title="donut-nested · pygal · anyplot.ai",
show_legend=True,
legend_at_bottom=True,
legend_at_bottom_columns=3,
print_values=True,
value_formatter=lambda x: f"${x}M",
margin=80,
)
# Add outer ring data (product lines with parent region labels)
for region, products in data.items():
for product_name, value in products.items():
outer_ring.add(f"{region}: {product_name}", [{"value": value, "label": product_name}])
# Create inner ring (region totals)
# This is a separate pie chart that will be composited on top of the outer ring
inner_ring = pygal.Pie(
width=int(width * 0.50),
height=int(height * 0.50),
style=inner_style,
inner_radius=0.45,
show_legend=False,
print_values=True,
value_formatter=lambda x: f"${x}M",
)
for label, value in zip(inner_labels, inner_values, strict=True):
inner_ring.add(label, [{"value": value, "label": label}])
# Render both rings to PNG bytes
# This is a creative compositing technique to achieve nested donuts in pygal
outer_png = outer_ring.render_to_png()
inner_png = inner_ring.render_to_png()
# Load rendered PNGs as PIL Images with transparency support
outer_img = Image.open(io.BytesIO(outer_png)).convert("RGBA")
inner_img = Image.open(io.BytesIO(inner_png)).convert("RGBA")
# Create background with the appropriate theme color
bg_color = (250, 248, 241, 255) if THEME == "light" else (26, 26, 23, 255)
combined = Image.new("RGBA", (width, height), bg_color)
# Paste outer ring (the full-sized pie chart with inner_radius cutout)
combined.paste(outer_img, (0, 0), outer_img)
# Calculate position to center inner ring inside the outer ring's cutout
inner_x = (width - inner_img.width) // 2
inner_y = (height - inner_img.height) // 2 - 40
# Paste inner ring (centered, composited on top)
combined.paste(inner_img, (inner_x, inner_y), inner_img)
# Convert to RGB and save as PNG with theme suffix
combined_rgb = combined.convert("RGB")
combined_rgb.save(f"plot-{THEME}.png")
# Save HTML version with interactive outer ring
html_style = Style(
background=PAGE_BG,
plot_background=PAGE_BG,
foreground=INK,
foreground_strong=INK,
foreground_subtle=INK_MUTED,
colors=tuple(outer_colors),
title_font_size=32,
label_font_size=20,
legend_font_size=18,
value_font_size=16,
)
html_chart = pygal.Pie(
width=width,
height=height,
style=html_style,
inner_radius=0.4,
title="donut-nested · pygal · anyplot.ai",
show_legend=True,
legend_at_bottom=True,
legend_at_bottom_columns=3,
print_values=True,
value_formatter=lambda x: f"${x}M",
)
for region, products in data.items():
for product_name, value in products.items():
html_chart.add(f"{region}: {product_name}", [{"value": value}])
html_chart.render_to_file(f"plot-{THEME}.html")
Part of Nested Donut Chart on anyplot.ai.