panes 0.3.0

Every layout engine you've found is welded to a renderer. You need the math without the framework.

panes is a spatial layout engine that computes rectangles without rendering them.

Describe panels in rows, columns, and presets. panes solves the geometry via Taffy's flexbox engine and hands back a map of PanelId → Rect. No framework. No widget system. No opinions about pixels.

Proof

use panes::{Layout, Rect};

let resolved = Layout::master_stack(["editor", "chat", "status"])
    .master_ratio(0.6)
    .gap(1.0)
    .resolve(80.0, 24.0)?;

for (id, rect) in resolved.iter() {
    println!("{id}: {rect:?}");
}
// PanelId(0): Rect { x: 0.0, y: 0.0, w: 47.5, h: 24.0 }
// PanelId(1): Rect { x: 48.5, y: 0.0, w: 31.5, h: 11.5 }
// PanelId(2): Rect { x: 48.5, y: 12.5, w: 31.5, h: 11.5 }

Install

cargo add panes

Usage

Pick a preset, build custom, or mutate at runtime.

// Preset — 15 built-in strategies
Layout::master_stack(["editor", "chat", "status"]).master_ratio(0.6).gap(1.0)

// Macro — declarative shorthand
let layout = layout! {
    row(gap: 8.0) {
        panel("editor", grow: 2.0)
        col {
            panel("chat")
            panel("status", fixed: 3.0)
        }
    }
}?;

// Runtime — strategy-driven mutations, focus, frame diffing
let mut rt = Layout::master_stack(["editor", "chat", "status"])
    .master_ratio(0.6).gap(1.0).into_runtime()?;

rt.add_panel("terminal".into())?;
rt.focus_next()?;

let frame = rt.resolve(80.0, 24.0)?;
let diff = frame.diff();

Adapters convert rects to renderer-native types:

Each adapter provides a panels() iterator that yields PanelEntry { id, kind, rect } — no hashmap, no cross-referencing:

for entry in panes_ratatui::panels(&resolved) {
    println!("{}: {} at {:?}", entry.id, entry.kind, entry.rect);
}

Performance

LayoutRuntime resolves a 100-panel flat layout in ~1µs on the hot path — roughly 3x over raw Taffy. The abstraction layer (tree compilation, rect resolution, frame diffing) adds minimal overhead.

See benches/ for methodology.

Documentation

See the User Guide for the full API: all 15 presets, the layout macro, TOML configuration, runtime mutations, frame diffing, animation, and render adapters.

License

MIT or Apache 2.0, at your option. See LICENSE-MIT and LICENSE-APACHE.