Pie / Donut API

Slices sized by share of a whole, with a donut mode one prop away (innerRadiusRatio) - see the Pie / Donut demo.

Import

Web Component

import "@michi-vz/wc/pie-chart";
// <michi-vz-pie-chart> is now defined

Vanilla JS

import { mountPieChart } from "@michi-vz/core";

const chart = mountPieChart(el, props);

Props

Prop	Type	Default	Description
dataSet*	PieDataItem[]	—	Array of slices; each value becomes a wedge sized by its share of the total
title	string	—	Optional chart title rendered above the plot
innerRadiusRatio	number	0	0 = full pie (default); (0,1) = donut hole as a fraction of the outer radius.
padAngle	number	0	Gap between slices in radians (default 0).
cornerRadius	number	0	Corner radius on the arcs in px (default 0).
sortByValue	boolean	true	Sort slices by value descending (default true); false keeps data order.
showLabels	boolean	true	Draw the % label inside each slice when it is large enough (default true).
showLegend	boolean	false	Render a swatch+label legend below the chart (default false).
filter	{ limit: number; sortingDir: "asc" | "desc" }	—	Keep only the top-N slices by value.
valueFormatter	(n: number) => string	—	Formats a numeric value for labels and tooltips
tooltipFormatter	(slice: PieSliceContext) => string	—	Returns custom tooltip HTML for a hovered datum (sanitized before it is inserted)
onHighlightItem	(labels: string[]) => void	—	Called when the hovered/highlighted label(s) change

Common props — shared by every chart (14)

Prop	Type	Default	Description
width	number	600	Chart width in pixels
height	number	420	Chart height in pixels
margin	Margin	{ top: 36, right: 8, bottom: 8, left: 8 }	Inner margins (top/right/bottom/left, in px) reserved for axes, titles, and labels
colors	string[]	—	Categorical palette for series/labels without an explicit colour or colorsMapping entry
colorsMapping	Record<string, string>	—	Explicit label -> colour map; takes precedence over the palette and per-item colours
highlightItems	string[]	—	Labels to emphasise; all other marks dim
disabledItems	string[]	—	Labels to hide and exclude from scales/stacks
renderer	"svg" | "canvas"	"svg"	Render as inline SVG (default) or to a canvas (faster for large datasets); getContext() is identical either way
locale	string	—	BCP-47 locale used for number and date formatting
skipColorMappingDispatch	boolean	false	External-CSS mode: unmapped labels resolve to transparent and onColorMappingGenerated is not emitted, so mark colours come from your CSS via the data-label-safe contract
enableTransitions	boolean	true	Animate updates with CSS transitions (default true)
onColorMappingGenerated	(mapping: Record<string, string>) => void	—	Called with the resolved label -> colour map after the chart assigns colours
onChartDataProcessed	(context: ChartContext) => void	—	Called with the renderer-agnostic ChartContext whenever the data is (re)processed
onDataWarning	(warnings: DataWarning[]) => void	—	Called with any non-fatal data warnings (duplicate labels, non-finite values, gaps, ...)

Events

The web component dispatches these bubbling CustomEvents (the engine exposes the same via the on* callbacks in the table above):

Event	Detail	Fires when
michi-vz:highlight	string[]	hover highlight changes
michi-vz:colormapping	Record<string, string>	a color mapping is generated
michi-vz:dataprocessed	ChartContext	data is (re)processed
michi-vz:datawarning	DataWarning[]	input warnings are detected

getContext()

mountPieChart(el, props).getContext() returns a renderer-agnostic PieChartContext: the mode ("pie" or "donut"), innerRadiusRatio, the slices (label / value / share / start & end angle), summary stats (slice count, total, largest slice), a deterministic natural-language summary, and an a11y table. See LLM context.

Source

Props are typed as PieChartProps in @michi-vz/core.