Pie

A circular part-to-whole chart. Use it for a small number of categories where the whole matters. The screenshot is captured from the native Fission chart gallery.

What the chart is for

Pie belongs to the Radial and polar family. Its job is to make this data shape readable: Label/value pairs. In a production interface, choose this chart when the visual form makes the user's question faster to answer than a table or a simpler chart would.

Avoid it for many categories or when small differences need precise comparison; a bar chart is usually clearer for ranking.

Data model

Label/value pairs. Keep the data close to the type that describes it. Fission Charts is typed Rust, so a line uses LineSeries, a calendar heatmap uses CalendarHeatmapSeries, and chart components such as zoom, marks, and graphics are explicit fields on Chart rather than hidden string configuration.

Rust API

Field	Type	Notes
title	&str	Names the chart for the screen, accessibility tree, and test output.
series	PieSeries	Holds label/value pairs plus donut and rose settings.
width / height	f32	Optional fixed size; omit them when the chart should flex inside Fission layout.

Example

use fission_charts::{Chart, PieSeries};

let chart = Chart::new()
    .title("Share")
    .series(vec![PieSeries::new("Share")
        .data(vec![("Search", 1048.0), ("Direct", 735.0), ("Email", 580.0), ("Ads", 484.0)])
        .into()]);

Interaction and animation

Charts can emit typed ChartInteractionEvent values when interaction is enabled. Handle those events in a reducer when the app needs hover, press, release, scroll, selection, or brush behavior. ChartAnimation stores duration, delay, stagger, easing, and reduced-motion behavior as deterministic chart data, so animation timing can be tested instead of being hidden in ad-hoc timers.

Testing guidance

For this chart, test the data mapping first, then test lowering, then capture a live screenshot when visual output changes. The screenshot for this page is refreshed with npm run charts:generate from the website package.

Tags: pie, part-to-whole.

Radial and polar family overview