Bar Chart

A bar chart renders categorical data as vertical bars. It has three modes — simple, grouped, and stacked — all built from the same BarPlot struct.

Import path: kuva::plot::BarPlot

Simple bar chart

Use .with_bar() or .with_bars() to add one bar per category, then .with_color() to set a uniform fill.

#![allow(unused)]
fn main() {
use kuva::plot::BarPlot;
use kuva::backend::svg::SvgBackend;
use kuva::render::render::render_multiple;
use kuva::render::layout::Layout;
use kuva::render::plots::Plot;

let plot = BarPlot::new()
    .with_bars(vec![
        ("Apples",     42.0),
        ("Bananas",    58.0),
        ("Cherries",   31.0),
        ("Dates",      47.0),
        ("Elderberry", 25.0),
    ])
    .with_color("steelblue");

let plots = vec![Plot::Bar(plot)];
let layout = Layout::auto_from_plots(&plots)
    .with_title("Bar Chart")
    .with_y_label("Count");

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

Adding bars individually

.with_bar(label, value) adds one bar at a time, which is useful when constructing data programmatically:

#![allow(unused)]
fn main() {
use kuva::plot::BarPlot;
let plot = BarPlot::new()
    .with_bar("A", 3.2)
    .with_bar("B", 4.7)
    .with_bar("C", 2.8)
    .with_color("steelblue");
}

Grouped bar chart

Use .with_group(label, values) to add a category with multiple side-by-side bars. Each item in values is a (value, color) pair — one per series. Call .with_legend() to label each series.

#![allow(unused)]
fn main() {
use kuva::plot::BarPlot;
use kuva::backend::svg::SvgBackend;
use kuva::render::render::render_multiple;
use kuva::render::layout::Layout;
use kuva::render::plots::Plot;

let plot = BarPlot::new()
    .with_group("Q1", vec![(18.0, "steelblue"), (12.0, "crimson"), (9.0,  "seagreen")])
    .with_group("Q2", vec![(22.0, "steelblue"), (17.0, "crimson"), (14.0, "seagreen")])
    .with_group("Q3", vec![(19.0, "steelblue"), (21.0, "crimson"), (11.0, "seagreen")])
    .with_group("Q4", vec![(25.0, "steelblue"), (15.0, "crimson"), (18.0, "seagreen")])
    .with_legend(vec!["Product A", "Product B", "Product C"]);

let plots = vec![Plot::Bar(plot)];
let layout = Layout::auto_from_plots(&plots)
    .with_title("Grouped Bar Chart")
    .with_y_label("Sales (units)");

let svg = SvgBackend.render_scene(&render_multiple(plots, layout));
}

Stacked bar chart

Add .with_stacked() to the same grouped structure to stack segments vertically instead of placing them side-by-side.

#![allow(unused)]
fn main() {
use kuva::plot::BarPlot;
use kuva::backend::svg::SvgBackend;
use kuva::render::render::render_multiple;
use kuva::render::layout::Layout;
use kuva::render::plots::Plot;

let plot = BarPlot::new()
    .with_group("Q1", vec![(18.0, "steelblue"), (12.0, "crimson"), (9.0,  "seagreen")])
    .with_group("Q2", vec![(22.0, "steelblue"), (17.0, "crimson"), (14.0, "seagreen")])
    .with_group("Q3", vec![(19.0, "steelblue"), (21.0, "crimson"), (11.0, "seagreen")])
    .with_group("Q4", vec![(25.0, "steelblue"), (15.0, "crimson"), (18.0, "seagreen")])
    .with_legend(vec!["Product A", "Product B", "Product C"])
    .with_stacked();

let plots = vec![Plot::Bar(plot)];
let layout = Layout::auto_from_plots(&plots)
    .with_title("Stacked Bar Chart")
    .with_y_label("Sales (units)");

let svg = SvgBackend.render_scene(&render_multiple(plots, layout));
}

Bar width

.with_width() controls how much of each category slot the bar fills. The default is 0.8; 1.0 means bars touch.

#![allow(unused)]
fn main() {
use kuva::plot::BarPlot;
let plot = BarPlot::new()
    .with_bars(vec![("A", 3.0), ("B", 5.0), ("C", 4.0)])
    .with_color("steelblue")
    .with_width(0.5);   // narrower bars with more whitespace
}

API reference

Choosing a mode