imgico (Wasm)

High-performance image to ICO/SVG converter for the browser, built with Rust and WebAssembly. This is the WebAssembly port of the imgico library, allowing client-side image conversion without server dependencies.

Features

• Client-side Conversion: Convert images directly in the browser.
• Fast & Efficient: Powered by Rust and WebAssembly.
• Small Footprint: Optimized for size (~430KB).
• Supports:
  • Image to ICO (multiple sizes)
  • Image to SVG (embedded PNG)

Build

To build the project from source:

1. Install Rust: https://rustup.rs/
2. Install wasm-pack:

cargo install wasm-pack

3. Build:

wasm-pack build --target web

This will generate a pkg directory which can be imported into your web application.

Usage

Initialization

You must initialize the Wasm module before using the conversion functions.

import init, { imgico, imgsvg } from './pkg/imgico.js';

async function main() {
  // Initialize the Wasm module
  await init();

  // Load image as Uint8Array
  const response = await fetch('input.png');
  const arrayBuffer = await response.arrayBuffer();
  const inputBuffer = new Uint8Array(arrayBuffer);

  // 1. Convert to ICO
  try {
    // Default sizes: [16, 32, 48, 64, 128, 256]
    const icoData = imgico(inputBuffer);

    // Download or use the ICO data
    download(icoData, 'icon.ico');
    // Custom sizes
    const customIcoData = imgico(inputBuffer, new Uint32Array([16, 32]));
  } catch (e) {
    console.error('ICO conversion failed:', e);
  }

  // 2. Convert to SVG
  try {
    // Optional size argument
    const svgData = imgsvg(inputBuffer, 512);

    // Convert bytes to string if needed
    const svgString = new TextDecoder().decode(svgData);
    console.log(svgString);
  } catch (e) {
    console.error('SVG conversion failed:', e);
  }
}

function download(data, filename) {
  const blob = new Blob([data], { type: 'application/octet-stream' });
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = filename;
  a.click();
  URL.revokeObjectURL(url);
}

main();

CLI Usage

You can also use imgico as a command-line tool.

Installation

cargo install --path .

Usage

imgico <input_file> [options]

Options:

• -f, --format <type>: Output format: 'ico' or 'svg' (default: ico)
• -h, --help: Show help message

Example:

imgico input.png -f ico

API

imgico(input, sizes?)

• input: Uint8Array - The input image data.
• sizes: Uint32Array | number[] (optional) - List of sizes to include in the ICO. Default: [16, 32, 48, 64, 128, 256].

Returns: Uint8Array (The generated ICO file data).

imgsvg(input, size?)

• input: Uint8Array - The input image data.
• size: number (optional) - The target width/height for the embedded image. If omitted, uses original size.

Returns: Uint8Array (The generated SVG file data as bytes).

License

ISC