test(barchart): add benchmarks (#455)

Cargo.toml

@@ -80,20 +80,24 @@ all-features = true
 cargo-args = ["-Zunstable-options", "-Zrustdoc-scrape-examples"]
 rustdoc-args = ["--cfg", "docsrs"]
 
+[[bench]]
+name = "barchart"
+harness = false
+
 [[bench]]
 name = "block"
 harness = false
 
 [[bench]]
-name = "paragraph"
+name = "list"
 harness = false
 
 [[bench]]
-name = "sparkline"
+name = "paragraph"
 harness = false
 
 [[bench]]
-name = "list"
+name = "sparkline"
 harness = false
 
 

benches/barchart.rs

@@ -0,0 +1,73 @@
+use criterion::{criterion_group, criterion_main, Bencher, BenchmarkId, Criterion};
+use rand::Rng;
+use ratatui::{
+    buffer::Buffer,
+    layout::Rect,
+    prelude::Direction,
+    widgets::{Bar, BarChart, BarGroup, Widget},
+};
+
+/// Benchmark for rendering a barchart.
+pub fn barchart(c: &mut Criterion) {
+    let mut group = c.benchmark_group("barchart");
+    let mut rng = rand::thread_rng();
+
+    for data_count in [64, 256, 2048] {
+        let data: Vec<Bar> = (0..data_count)
+            .map(|i| {
+                Bar::default()
+                    .label(format!("B{i}").into())
+                    .value(rng.gen_range(0..data_count))
+            })
+            .collect();
+
+        let bargroup = BarGroup::default().bars(&data);
+
+        // Render a basic barchart
+        group.bench_with_input(
+            BenchmarkId::new("render", data_count),
+            &BarChart::default().data(bargroup.clone()),
+            render,
+        );
+
+        // Render an horizontal barchart
+        group.bench_with_input(
+            BenchmarkId::new("render_horizontal", data_count),
+            &BarChart::default()
+                .direction(Direction::Horizontal)
+                .data(bargroup.clone()),
+            render,
+        );
+
+        // Render a barchart with multiple groups
+        group.bench_with_input(
+            BenchmarkId::new("render_grouped", data_count),
+            &BarChart::default()
+                // We call `data` multiple time to add multiple groups.
+                // This is not a duplicated call.
+                .data(bargroup.clone())
+                .data(bargroup.clone())
+                .data(bargroup.clone()),
+            render,
+        );
+    }
+
+    group.finish();
+}
+
+/// Render the widget in a classical size buffer
+fn render(bencher: &mut Bencher, barchart: &BarChart) {
+    let mut buffer = Buffer::empty(Rect::new(0, 0, 200, 50));
+    // We use `iter_batched` to clone the value in the setup function.
+    // See https://github.com/ratatui-org/ratatui/pull/377.
+    bencher.iter_batched(
+        || barchart.clone(),
+        |bench_barchart| {
+            bench_barchart.render(buffer.area, &mut buffer);
+        },
+        criterion::BatchSize::LargeInput,
+    )
+}
+
+criterion_group!(benches, barchart);
+criterion_main!(benches);