egui/crates/egui_demo_lib/benches/benchmark.rs

use criterion::{criterion_group, criterion_main, Criterion};

use egui::epaint::TextShape;
use egui_demo_lib::LOREM_IPSUM_LONG;

pub fn criterion_benchmark(c: &mut Criterion) {
    use egui::RawInput;

    {
        let ctx = egui::Context::default();
        let mut demo_windows = egui_demo_lib::DemoWindows::default();

        // The most end-to-end benchmark.
        c.bench_function("demo_with_tessellate__realistic", |b| {
            b.iter(|| {
                let full_output = ctx.run(RawInput::default(), |ctx| {
                    demo_windows.ui(ctx);
                });
                ctx.tessellate(full_output.shapes)
            });
        });

        c.bench_function("demo_no_tessellate", |b| {
            b.iter(|| {
                ctx.run(RawInput::default(), |ctx| {
                    demo_windows.ui(ctx);
                })
            });
        });

        let full_output = ctx.run(RawInput::default(), |ctx| {
            demo_windows.ui(ctx);
        });
        c.bench_function("demo_only_tessellate", |b| {
            b.iter(|| ctx.tessellate(full_output.shapes.clone()));
        });
    }

    if false {
        let ctx = egui::Context::default();
        ctx.memory_mut(|m| m.set_everything_is_visible(true)); // give us everything
        let mut demo_windows = egui_demo_lib::DemoWindows::default();
        c.bench_function("demo_full_no_tessellate", |b| {
            b.iter(|| {
                ctx.run(RawInput::default(), |ctx| {
                    demo_windows.ui(ctx);
                })
            });
        });
    }

    {
        let ctx = egui::Context::default();
        let _ = ctx.run(RawInput::default(), |ctx| {
            egui::CentralPanel::default().show(ctx, |ui| {
                c.bench_function("label &str", |b| {
                    b.iter(|| {
                        ui.label("the quick brown fox jumps over the lazy dog");
                    });
                });
                c.bench_function("label format!", |b| {
                    b.iter(|| {
                        ui.label("the quick brown fox jumps over the lazy dog".to_owned());
                    });
                });
            });
        });
    }

    {
        let ctx = egui::Context::default();
        ctx.begin_frame(RawInput::default());

        egui::CentralPanel::default().show(&ctx, |ui| {
            c.bench_function("Painter::rect", |b| {
                let painter = ui.painter();
                let rect = ui.max_rect();
                b.iter(|| {
                    painter.rect(rect, 2.0, egui::Color32::RED, (1.0, egui::Color32::WHITE));
                });
            });
        });

        // Don't call `end_frame` to not have to drain the huge paint list
    }

    {
        let pixels_per_point = 1.0;
        let max_texture_side = 8 * 1024;
        let wrap_width = 512.0;
        let font_id = egui::FontId::default();
        let color = egui::Color32::WHITE;
        let fonts = egui::epaint::text::Fonts::new(
            pixels_per_point,
            max_texture_side,
            egui::FontDefinitions::default(),
        );
        {
            let mut locked_fonts = fonts.lock();
            c.bench_function("text_layout_uncached", |b| {
                b.iter(|| {
                    use egui::epaint::text::{layout, LayoutJob};

                    let job = LayoutJob::simple(
                        LOREM_IPSUM_LONG.to_owned(),
                        font_id.clone(),
                        color,
                        wrap_width,
                    );
                    layout(&mut locked_fonts.fonts, job.into())
                });
            });
        }
        c.bench_function("text_layout_cached", |b| {
            b.iter(|| {
                fonts.layout(
                    LOREM_IPSUM_LONG.to_owned(),
                    font_id.clone(),
                    color,
                    wrap_width,
                )
            });
        });

        let galley = fonts.layout(LOREM_IPSUM_LONG.to_owned(), font_id, color, wrap_width);
        let font_image_size = fonts.font_image_size();
        let prepared_discs = fonts.texture_atlas().lock().prepared_discs();
        let mut tessellator = egui::epaint::Tessellator::new(
            1.0,
            Default::default(),
            font_image_size,
            prepared_discs,
        );
        let mut mesh = egui::epaint::Mesh::default();
        let text_shape = TextShape::new(egui::Pos2::ZERO, galley);
        c.bench_function("tessellate_text", |b| {
            b.iter(|| {
                tessellator.tessellate_text(&text_shape, &mut mesh);
                mesh.clear();
            });
        });
    }
}

criterion_group!(benches, criterion_benchmark);
criterion_main!(benches);