speice.io/blog/2024-11-15-playing-with-fire/1-introduction/chaosGameWeighted.ts

// hidden-start
import { randomBiUnit } from "../src/randomBiUnit";
import { randomChoice } from "../src/randomChoice";
import { plot } from "./plot";
import { Transform } from "../src/transform";

const quality = 0.5;
const step = 1000;
// hidden-end
export type Props = {
  width: number,
  height: number,
  transforms: [number, Transform][]
}

export function* chaosGameWeighted(
  { width, height, transforms }: Props
) {
  let img =
    new ImageData(width, height);
  let [x, y] = [
    randomBiUnit(),
    randomBiUnit()
  ];

  const pixels = width * height;
  const iterations = quality * pixels;
  for (let i = 0; i < iterations; i++) {
    // highlight-start
    const [_, xform] =
      randomChoice(transforms);
    // highlight-end
    [x, y] = xform(x, y);

    if (i > 20)
      plot(x, y, img);

    if (i % step === 0)
      yield img;
  }

  yield img;
}