@trailstash/ultra/lib/sprites.js

A web based tool for making MapLibre GL maps with data from sources such as Overpass, GeoJSON, GPX, KML, TCX, etc

const fetchedImages = {};
export const handleStyleImageMissing = async (ev) => {
  const builtin = ev.id.match(/\/icons\/(maki|temaki)\/(.*)\.png/);
  if (ev.id.startsWith("https://") || ev.id.startsWith("data:")) {
    if (!fetchedImages[ev.id]) {
      fetchedImages[ev.id] = true;
      const image = new Image();
      image.crossOrigin = "anonymous";
      image.src = ev.id;
      await image.decode();
      ev.target.addImage(
        ev.id,
        image,
        Object.fromEntries(new URLSearchParams(new URL(ev.id).hash.slice(1))),
      );
    }
  }
  if (builtin) {
    const { data, pixelRatio, sdf } = ev.target.getImage(
      builtin.slice(1, 3).join(":"),
    );
    ev.target.addImage(ev.id, data, { data, pixelRatio, sdf });
  }
};