# Pie (/docs/charts/pie)

> Nonnegative parts of one positive total, with keyed angular motion and direct transitions.

```ts
import { pie } from 'visdelta/pie';
```

`pie()` shows nonnegative parts of one positive total. Every row is one keyed
slice.

<LiveExample id="pie-donut" />

## Methods [#methods]

| Method                                    | Meaning                                              |
| ----------------------------------------- | ---------------------------------------------------- |
| `.value(field, options?)`                 | Bind the slice magnitude (`encoding.angle`)          |
| `.label(field)`                           | Bind the slice label (`encoding.label`)              |
| `.labels('inside' \| 'outside' \| 'none')` | Place labels; `outside` is the default              |
| `.innerRadius(fraction)`                  | Create a donut; the fraction must be in `[0, 1)`     |

Input order determines clockwise slice order, starting at the top. `.sort()`
changes that order explicitly. `.where()`, `.highlight()`, colour and tooltips
are supported.

Outside labels have leader lines and vertical spacing. Names that exceed the
available gutter are shortened, and the full values stay in the tooltip.

## Validation [#validation]

Pie validates its input instead of guessing:

- Repeated categories are rejected; aggregate them before building the chart.
- Negative, missing and non-finite values, and a non-positive total, are
  rejected.
- Zero-valued components have no visible sector.
- Cartesian position channels, axes and `focus()` are rejected.

## Transition behaviour [#transition-behaviour]

Pie uses the direct runtime transition with recorded angular and radial motion
and keyed enter and exit. Slices move as wedges rather than as interpolated SVG
path strings.

It has no declaration-operation planner, automatic intermediate states, focus
camera or cross-chart geometry bridge. A Pie state cannot transition into
another chart type.