# Pie chart

> Dashboard component reference for the Pie chart, how a whole divides across live points, with every editor property.

The **Pie chart** shows how a whole divides: one slice per address, read at this moment,
as a pie, a doughnut or a half doughnut. Like the [Bar chart](component-bar-chart) it is
a categorical chart — no time axis, no window, no cadence, no retention. The two share
their content, points and format sections; only the drawing below differs.

A point that is not reading is left out of the comparison instead of being drawn at zero,
and the chart says so under the drawing. A screen that has only just opened says nothing
yet.

## Content and points {#content-and-points}

| Property | What it does | Values | Default |
|---|---|---|---|
| Chart title | Optional heading drawn inside the plot. This is the chart's own heading, not the component's corner title (that one lives in the shared Appearance section). | text | empty |
| Points | The categories compared, one card per slice, in the order declared. **Add point** appends one. | list | empty |
| — Address | Rooted Logic address the slice reads. The field suggests from the live point list, filtered to numeric points, and shows the point's current reading once named. | address | empty |
| — Name | What the labels and the legend call the slice. | text | blank falls back to the address |
| — Color | The slice's ink as `#RRGGBB`. | hex color | blank takes the palette's turn |
| Order | The order the slices are drawn in. | as declared · smallest first · largest first | as declared |

## Format {#format}

| Property | What it does | Values | Default |
|---|---|---|---|
| Unit | Optional engineering unit written after each reading. | text | empty |
| Decimals | Fixed decimal places for the readings. | 0 to 15 | blank uses the station's preference |
| Reads as | How each reading is written out — in the labels and the tooltips alike. | Number · Percentage · Duration | Number |
| The value counts | What one unit of the value means while the format is a duration. | Seconds · Milliseconds · Minutes | Seconds |

## Slices {#slices}

| Property | What it does | Values | Default |
|---|---|---|---|
| Shape | The body the slices are taken out of. All three answer the same question and differ in what the middle is for: a full disc gives every slice the most area, a ring frees the centre, and half a ring fits the wide, short cell a row of cards leaves. | Pie · Doughnut · Half doughnut | Pie |
| Labels | What is written beside each slice. The name is always part of a drawn label — a number floating beside an unnamed wedge says nothing — and the choice is what accompanies it. Choosing nothing leaves the legend to name the slices, which is what a small cell wants. | Name only · Name and reading · Name and share · Name, reading and share · Nothing | Name and share |
| Labels sit | Where the writing sits. Outside costs ring diameter and leader lines but never runs out of room; inside spends none of the cell on the labels and needs a slice wide enough to hold one. Only asked while labels are drawn at all. | outside the ring · inside the slice | outside the ring |
| Legend | Where the legend sits. | over the plot · under the plot · none | over the plot |

## Scale bands {#scale-bands}

The **Scale** section declares stretches of the value range through the shared band
editor. On a pie the bands are a palette: they tint each slice by where its reading
falls, and nothing more — slices of one whole have no single stretch the drawing is *in*,
so no wording field and no reference are offered. A reading past the last bound keeps the
slice's authored ink.

## Toolbox {#toolbox}

| Tool | What it does | In the default set |
|---|---|---|
| Save as PNG | Downloads the drawing as a PNG. | yes |
| Copy as PNG | Puts the drawing on the clipboard as a PNG. | yes |
| Full screen | Fills the window with this chart. | yes |