smitters - Smith chart math and drawing

Rust library for Smith chart (Volpert-Smith chart) math and rendering.

Core math is UI-agnostic. Includes ready-to-use egui integration for interactive charts.

Web demo

https://n4n5.dev/smitters/ thanks to @Its-Just-Nans

Examples

cargo run --example hello
# or
cargo run --example show

Web version

rustup target add wasm32-unknown-unknown
cargo install trunk --locked

# Dev server with hot reload
trunk serve --example show

# Production build
trunk build --example show --release --public-url ./

Features

• Convert between impedance (R + jX) and Smith chart coordinates
• Constant resistance and constant reactance circle math
• Arc rendering via Bezier curves (using kurbo)
• Two grid styles: simple and fancy (detailed multi-patch grid)
• Interactive hover: mouse position to impedance readout
• Optional egui integration behind egui-integration feature (enabled by default)

Quick start

[dependencies]
smitters = "0.2"

Run the interactive demo:

cargo run --example demo

The demo lets you:

• Switch between simple and fancy grid styles
• Hover over the chart to see R and X values in real time
• Place an impedance point by entering R and X values

Other examples:

cargo run --example hello   # basic chart with grid toggle
cargo run --example show    # hover-based impedance display

Usage

Math only (no GUI dependency)

use smitters::math::{resistance_to_xy, xy_to_resistance, ResActive, ResReactive};

// Impedance to chart coordinates
let pos = resistance_to_xy(ResActive(1.0), ResReactive(0.5), 100.0);

// Chart coordinates to impedance
let (r, x) = xy_to_resistance(&pos);

With egui

use smitters::{chart_fancy::draw_smith_fancy, context::Context};

// Inside your egui update:
let ctx = Context::get_context(ui);
draw_smith_fancy(&ctx);

Architecture

| Module | Description | |--------|-------------| | math | Core types (ResActive, ResReactive, Pos2, Circle) and coordinate transforms | | trigonometry | Circle intersection and chord angle calculations | | drawing_primitives | Arc segment computation for constant-R and constant-X lines | | egui | Bezier curve rendering with egui painter | | context | Drawing context that wraps egui painter with Smith chart utilities | | chart_simple | Simple grid renderer | | chart_fancy | Detailed multi-resolution grid renderer |

License

MIT