Gif.js

Uses web workers to render frames in background threads, significantly speeding up encoding as emphasized in the README's focus on performance.

Supports adding frames from image elements, canvas elements, or canvas contexts, making it versatile for various web app scenarios without server dependencies.

Offers configurable settings like quality, dithering methods, repeat count, and transparency, allowing fine-tuned control over the output GIF.

Encodes GIFs directly in the browser, enabling real-time previews and reducing server load, as highlighted in the value proposition.