Sunburst Chart

A sunburst chart displays hierarchical data as concentric rings. Each ring represents one depth level; arc widths within a ring are proportional to node values. Uses the same TreemapNode data model as the TreemapPlot.

Import path: kuva::plot::sunburst::SunburstPlot, kuva::plot::sunburst::SunburstColorMode, kuva::plot::treemap::TreemapNode, kuva::plot::ColorMap

Basic usage

#![allow(unused)]
fn main() {
use kuva::plot::sunburst::SunburstPlot;
use kuva::plot::treemap::TreemapNode;
use kuva::backend::svg::SvgBackend;
use kuva::render::render::render_multiple;
use kuva::render::layout::Layout;
use kuva::render::plots::Plot;

let plot = SunburstPlot::new()
    .with_node(TreemapNode::new("Root", vec![
        TreemapNode::leaf("A", 30.0),
        TreemapNode::leaf("B", 45.0),
        TreemapNode::leaf("C", 25.0),
    ]));

let plots = vec![Plot::Sunburst(plot)];
let layout = Layout::auto_from_plots(&plots).with_title("Sunburst");
let svg = SvgBackend.render_scene(&render_multiple(plots, layout));
std::fs::write("sunburst.svg", svg).unwrap();
}

Hierarchical data (multiple levels)

Use TreemapNode::new(label, children) for inner nodes. Values auto-sum from children when value = 0.0.

#![allow(unused)]
fn main() {
use kuva::plot::sunburst::SunburstPlot;
use kuva::plot::treemap::TreemapNode;
use kuva::render::{plots::Plot, layout::Layout, render::render_multiple};
use kuva::backend::svg::SvgBackend;
let plot = SunburstPlot::new()
    .with_node(TreemapNode::new("Animals", vec![
        TreemapNode::new("Mammals", vec![
            TreemapNode::leaf("Dog",  40.0),
            TreemapNode::leaf("Cat",  35.0),
            TreemapNode::leaf("Bear", 25.0),
        ]),
        TreemapNode::new("Birds", vec![
            TreemapNode::leaf("Eagle",  60.0),
            TreemapNode::leaf("Parrot", 40.0),
        ]),
    ]));
}

Multiple roots (forest)

Multiple root nodes share the innermost ring, each receiving a distinct category color.

#![allow(unused)]
fn main() {
use kuva::plot::sunburst::SunburstPlot;
use kuva::plot::treemap::TreemapNode;
let plot = SunburstPlot::new()
    .with_children("Frontend", vec![
        TreemapNode::leaf("React", 50.0),
        TreemapNode::leaf("Vue",   30.0),
        TreemapNode::leaf("Svelte", 20.0),
    ])
    .with_children("Backend", vec![
        TreemapNode::leaf("Rust",   40.0),
        TreemapNode::leaf("Go",     35.0),
        TreemapNode::leaf("Python", 25.0),
    ]);
}

Donut style

Set .with_inner_radius(frac) where frac is the fractional inner hole size (0.0 = solid disc, 0.3 = 30% hole).

#![allow(unused)]
fn main() {
use kuva::plot::sunburst::SunburstPlot;
use kuva::plot::treemap::TreemapNode;
let plot = SunburstPlot::new()
    .with_node(TreemapNode::new("Root", vec![
        TreemapNode::leaf("A", 40.0),
        TreemapNode::leaf("B", 35.0),
        TreemapNode::leaf("C", 25.0),
    ]))
    .with_inner_radius(0.35);   // 35% inner hole
}

Color modes

By parent (default)

Each root node gets a distinct category10 color; descendants inherit it.

#![allow(unused)]
fn main() {
use kuva::plot::sunburst::{SunburstPlot, SunburstColorMode};
use kuva::plot::treemap::TreemapNode;
let plot = SunburstPlot::new()
    .with_children("Group A", vec![
        TreemapNode::leaf("X", 40.0),
        TreemapNode::leaf("Y", 60.0),
    ])
    .with_color_mode(SunburstColorMode::ByParent);
}

By value

Color arcs by a continuous colormap. Parent arcs appear as neutral #e0e0e0.

#![allow(unused)]
fn main() {
use kuva::plot::sunburst::{SunburstPlot, SunburstColorMode};
use kuva::plot::treemap::TreemapNode;
use kuva::plot::ColorMap;
let plot = SunburstPlot::new()
    .with_node(TreemapNode::new("Root", vec![
        TreemapNode::leaf("A", 30.0),
        TreemapNode::leaf("B", 45.0),
        TreemapNode::leaf("C", 25.0),
    ]))
    .with_color_mode(SunburstColorMode::ByValue(ColorMap::Viridis))
    .with_colorbar(true)
    .with_colorbar_label("Score");
}

Explicit

Use TreemapNode::leaf_colored(label, value, css_color) for per-node CSS colors.

#![allow(unused)]
fn main() {
use kuva::plot::sunburst::{SunburstPlot, SunburstColorMode};
use kuva::plot::treemap::TreemapNode;
let plot = SunburstPlot::new()
    .with_node(TreemapNode::new("Root", vec![
        TreemapNode::leaf_colored("Red slice",  40.0, "#e74c3c"),
        TreemapNode::leaf_colored("Blue slice", 35.0, "#3498db"),
        TreemapNode::leaf_colored("Green slice",25.0, "#2ecc71"),
    ]))
    .with_color_mode(SunburstColorMode::Explicit);
}

Second-dimension coloring (color_values)

For GO enrichment-style charts: size = gene count, color = p-value (independent of arc size).

#![allow(unused)]
fn main() {
use kuva::plot::sunburst::{SunburstPlot, SunburstColorMode};
use kuva::plot::treemap::TreemapNode;
use kuva::plot::ColorMap;
let terms = vec![
    ("GO:0006955 immune response",      120_usize, 1e-10_f64),
    ("GO:0007049 cell cycle",            85,        2e-7),
    ("GO:0016310 phosphorylation",       60,        5e-5),
];

let mut plot = SunburstPlot::new();
let mut pvalues = Vec::new();
for (label, count, pval) in &terms {
    plot = plot.with_node(TreemapNode::leaf(label.to_string(), *count as f64));
    pvalues.push(-pval.log10());   // –log₁₀(p) so high = significant
}
let plot = plot
    .with_color_values(pvalues)
    .with_color_mode(SunburstColorMode::ByValue(ColorMap::Viridis))
    .with_colorbar(true)
    .with_colorbar_label("−log₁₀(p)");
}

Start angle and depth limit

#![allow(unused)]
fn main() {
use kuva::plot::sunburst::SunburstPlot;
use kuva::plot::treemap::TreemapNode;
let plot = SunburstPlot::new()
    .with_node(TreemapNode::new("Root", vec![
        TreemapNode::leaf("A", 30.0),
        TreemapNode::leaf("B", 70.0),
    ]))
    .with_start_angle(90.0)   // start from east instead of north
    .with_max_depth(2)        // limit to 2 rings
    .with_ring_gap(2.0);      // wider gap between rings
}

Builder reference