test(block): add benchmarks (#368)

Added benchmarks to the block widget to uncover eventual performance issues

Cargo.toml

@@ -61,6 +61,11 @@ rand = "0.8"
 name = "paragraph"
 harness = false
 
+[[bench]]
+name = "block"
+harness = false
+
+
 [[example]]
 name = "barchart"
 required-features = ["crossterm"]

benches/block.rs

@@ -0,0 +1,58 @@
+use criterion::{criterion_group, criterion_main, Bencher, BenchmarkId, Criterion};
+use ratatui::{
+    buffer::Buffer,
+    layout::Rect,
+    prelude::Alignment,
+    widgets::{
+        block::{Position, Title},
+        Block, Borders, Padding, Widget,
+    },
+};
+
+/// Benchmark for rendering a block.
+pub fn block(c: &mut Criterion) {
+    let mut group = c.benchmark_group("block");
+
+    for buffer_size in &[
+        Rect::new(0, 0, 100, 50),  // vertically split screen
+        Rect::new(0, 0, 200, 50),  // 1080p fullscreen with medium font
+        Rect::new(0, 0, 256, 256), // Max sized area
+    ] {
+        let buffer_area = buffer_size.area();
+
+        // Render an empty block
+        group.bench_with_input(
+            BenchmarkId::new("render_empty", buffer_area),
+            &Block::new(),
+            |b, block| render(b, block, buffer_size),
+        );
+
+        // Render with all features
+        group.bench_with_input(
+            BenchmarkId::new("render_all_feature", buffer_area),
+            &Block::new()
+                .borders(Borders::ALL)
+                .title("test title")
+                .title(
+                    Title::from("bottom left title")
+                        .alignment(Alignment::Right)
+                        .position(Position::Bottom),
+                )
+                .padding(Padding::new(5, 5, 2, 2)),
+            |b, block| render(b, block, buffer_size),
+        );
+    }
+
+    group.finish();
+}
+
+/// render the block into a buffer of the given `size`
+fn render(bencher: &mut Bencher, block: &Block, size: &Rect) {
+    let mut buffer = Buffer::empty(*size);
+    bencher.iter(|| {
+        block.clone().render(buffer.area, &mut buffer);
+    })
+}
+
+criterion_group!(benches, block);
+criterion_main!(benches);