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PiePlot

Builder for creating pie or donut charts. Each slice has its own explicit color. Slice labels can be positioned automatically, forced inside or outside, or suppressed entirely in favor of a legend. Percentage values can be appended to labels with with_percent(). Render with render_pie for most cases, or render_multiple when a legend is attached.

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Constructor

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PiePlot::new()
Self
Create a pie chart with default settings.Defaults:
  • Full pie (inner_radius = 0.0)
  • Auto label positioning
  • No percentages
  • No legend
  • min_label_fraction = 0.05 (5%)

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Data Methods

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with_slice
Self
pub fn with_slice<L, V, C>(self, label: L, value: V, color: C) -> Self
where
    L: Into<String>,
    V: Into<f64>,
    C: Into<String>
Add a slice with a label, value, and fill color. Slices are drawn clockwise in the order they are added, starting from the top (12 o’clock). The value is proportional — only the ratio between values matters, not their absolute magnitude.Example:
let pie = PiePlot::new()
    .with_slice("A", 60.0, "steelblue")
    .with_slice("B", 40.0, "tomato");

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Styling Methods

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with_inner_radius
Self
pub fn with_inner_radius(self, r: f64) -> Self
Set the inner radius in pixels to create a donut chart. A value of 0.0 (the default) renders a solid pie. Any positive value cuts a hollow centre. Typical values are in the range 40.0–80.0 depending on the canvas size.Example:
let donut = PiePlot::new()
    .with_slice("A", 60.0, "steelblue")
    .with_slice("B", 40.0, "tomato")
    .with_inner_radius(60.0);

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Label Methods

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with_label_position
Self
pub fn with_label_position(self, pos: PieLabelPosition) -> Self
Set the label placement strategy. See PieLabelPosition for the available options. The default is Auto.
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with_percent
Self
pub fn with_percent(self) -> Self
Append the percentage of the total to each slice label. The percentage is computed from the slice values and formatted to one decimal place (e.g. "Rust 40.0%").
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with_min_label_fraction
Self
pub fn with_min_label_fraction(self, fraction: f64) -> Self
Set the minimum slice fraction below which no label is drawn. Slices whose value is less than fraction of the total are silently skipped. The default is 0.05 (5%). Set to 0.0 to label every slice regardless of size.Example:
// Label all slices, even tiny ones
let pie = PiePlot::new()
    .with_slice("Big",  90.0, "steelblue")
    .with_slice("Tiny",  1.0, "tomato")
    .with_min_label_fraction(0.0);

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Legend Methods

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with_legend
Self
pub fn with_legend<S: Into<String>>(self, label: S) -> Self
Attach a legend to the pie chart. When a legend label is set, render_multiple adds a per-slice legend entry (colored square + slice label) in the right margin. Combine with with_label_position(PieLabelPosition::None) to use the legend as the sole means of identification.Example:
let pie = PiePlot::new()
    .with_slice("A", 60.0, "steelblue")
    .with_slice("B", 40.0, "tomato")
    .with_legend("Category")
    .with_label_position(PieLabelPosition::None);

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Enums & Types

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PieLabelPosition

Controls where slice labels are placed relative to each slice. Default is Auto.
  • Inside - Labels centered between the inner and outer radius (or at mid-radius for a full pie). Works well when all slices are large enough to fit text.
  • Outside - Labels placed outside the pie with leader lines connecting them to their slice. Small slices are automatically spaced to avoid label overlap.
  • Auto - Inside for large slices; outside with a leader line for small ones. This is the default. The threshold is controlled by with_min_label_fraction.
  • None - No slice labels. Combine with with_legend to identify slices via a legend instead.

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PieSlice

A single slice of a pie chart. Fields:
  • label: String - Slice label
  • value: f64 - Slice value (proportional)
  • color: String - Fill color (CSS color string)

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Complete Example

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Simple Pie Chart

use kuva::plot::{PiePlot, PieLabelPosition};
use kuva::backend::svg::SvgBackend;
use kuva::render::render::render_pie;
use kuva::render::layout::Layout;
use kuva::render::plots::Plot;

let pie = PiePlot::new()
    .with_slice("Rust",   40.0, "steelblue")
    .with_slice("Python", 30.0, "tomato")
    .with_slice("R",      20.0, "seagreen")
    .with_slice("Other",  10.0, "gold")
    .with_percent();

let plots = vec![Plot::Pie(pie.clone())];
let layout = Layout::auto_from_plots(&plots).with_title("Language usage");

let svg = SvgBackend.render_scene(&render_pie(&pie, &layout));
std::fs::write("pie.svg", svg).unwrap();

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Donut Chart

use kuva::plot::{PiePlot, PieLabelPosition};
use kuva::backend::svg::SvgBackend;
use kuva::render::render::render_pie;
use kuva::render::layout::Layout;
use kuva::render::plots::Plot;

let donut = PiePlot::new()
    .with_slice("Product A", 45.0, "steelblue")
    .with_slice("Product B", 35.0, "crimson")
    .with_slice("Product C", 20.0, "seagreen")
    .with_inner_radius(60.0)
    .with_percent();

let plots = vec![Plot::Pie(donut.clone())];
let layout = Layout::auto_from_plots(&plots).with_title("Market Share");

let svg = SvgBackend.render_scene(&render_pie(&donut, &layout));
std::fs::write("donut.svg", svg).unwrap();

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Pie Chart with Legend Only

use kuva::plot::{PiePlot, PieLabelPosition};
use kuva::backend::svg::SvgBackend;
use kuva::render::render::render_multiple;
use kuva::render::layout::Layout;
use kuva::render::plots::Plot;

let pie = PiePlot::new()
    .with_slice("Category A", 35.0, "steelblue")
    .with_slice("Category B", 25.0, "crimson")
    .with_slice("Category C", 20.0, "seagreen")
    .with_slice("Category D", 15.0, "gold")
    .with_slice("Category E", 5.0, "purple")
    .with_legend("Categories")
    .with_label_position(PieLabelPosition::None);

let plots = vec![Plot::Pie(pie)];
let layout = Layout::auto_from_plots(&plots).with_title("Distribution by Category");

let svg = SvgBackend.render_scene(&render_multiple(plots, layout));
std::fs::write("pie_legend.svg", svg).unwrap();

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