Performance Overview

Performance is an architectural requirement for Bevy-based user interfaces. In a UI framework, performance is not just about frames; it is about how much state churn, layout work, and asset cost the system creates while users work with the interface.

Design principles

• keep updates local and predictable
• limit unnecessary re-render and re-layout work
• avoid expensive pattern growth in large lists or dense tables
• preserve a stable layout while data changes underneath it
• keep rendering and interaction cost proportional to the actual user task

Example: constrained list workload

#![allow(unused)]
fn main() {
use bevy::prelude::*;
use beverly::prelude::*;

fn build_data_view(mut commands: Commands) {
    commands.spawn((
        NodeBundle::default(),
        BeverlyList::new(),
    )).with_children(|list| {
        for i in 0..50 {
            list.spawn(BeverlyListItem::new(format!("Item {i}")));
        }
    });
}
}

This keeps the content model explicit and understandable. For larger workloads, virtualization or paginated patterns are better than rendering every item with equal visual weight.

Guidance

Performance decisions should be visible in the architecture. A user interface that feels fast should also scale well when the data model grows, the screen becomes denser, or motion and effects become more complex.