ringgrid-wasm

WebAssembly bindings for ringgrid — a pure-Rust detector for dense coded ring calibration targets.

Building

wasm-pack build crates/ringgrid-wasm --target web --release

Usage

import init, { RinggridDetector, default_board_json } from './pkg/ringgrid_wasm.js';

await init();

const detector = new RinggridDetector(default_board_json());

// From canvas ImageData (RGBA)
const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
const resultJson = detector.detect_rgba(imageData.data, canvas.width, canvas.height);
const result = JSON.parse(resultJson);

console.log(`Found ${result.detected_markers.length} markers`);
for (const m of result.detected_markers) {
    console.log(`  Marker ${m.id} at (${m.center[0].toFixed(1)}, ${m.center[1].toFixed(1)})`);
}

API

RinggridDetector

| Method | Input | Output | |--------|-------|--------| | new(board_json) | Board layout JSON string | RinggridDetector | | with_marker_scale(board_json, min_px, max_px) | Board + scale range | RinggridDetector | | with_marker_diameter(board_json, diameter_px) | Board + diameter hint | RinggridDetector | | detect(pixels, w, h) | Grayscale Uint8Array | JSON DetectionResult | | detect_rgba(pixels, w, h) | RGBA Uint8Array | JSON DetectionResult | | detect_adaptive(pixels, w, h) | Grayscale Uint8Array | JSON DetectionResult | | detect_adaptive_rgba(pixels, w, h) | RGBA Uint8Array | JSON DetectionResult | | propose_with_heatmap(pixels, w, h) | Grayscale Uint8Array | JSON proposals | | propose_with_heatmap_rgba(pixels, w, h) | RGBA Uint8Array | JSON proposals | | heatmap_f32() | — | Float32Array (row-major) | | heatmap_width() / heatmap_height() | — | number |

Free functions

| Function | Output | |----------|--------| | default_board_json() | Default board layout JSON string | | version() | Package version string |

Output format

Detection results are returned as JSON strings matching the Rust DetectionResult type. Key fields:

• detected_markers[].id — codebook index (0–892)
• detected_markers[].center — [x, y] pixel coordinates
• detected_markers[].confidence — detection confidence (0–1)
• detected_markers[].ellipse_outer / ellipse_inner — fitted ellipse parameters
• homography — 3x3 board-to-image homography matrix (if available)

Heatmap is a row-major Float32Array of size width * height, representing the RSD vote accumulator.