speice.io/posts/2023/06/flam3/2b-post.ts

import {
  Coefs,
  Variation,
  Flame,
  Transform,
  linear,
  julia,
  popcorn,
  pdj,
  render,
  transform1Weight,
  transform1,
  transform2Weight,
  transform2,
  transform3Weight,
  transform3,
} from "./2a-variations";

export class TransformPost extends Transform {
  constructor(
    coefs: Coefs,
    variations: [number, Variation][],
    public readonly post: Coefs
  ) {
    super(coefs, variations);
  }

  apply(x: number, y: number): [number, number] {
    const [transformX, transformY] = super.apply(x, y);
    return [
      transformX * this.post.a + transformY * this.post.b + this.post.c,
      transformX * this.post.d + transformY * this.post.e + this.post.f,
    ];
  }
}

export function variationPost(coefs: Coefs, variation: Variation): Variation {
  return (x, y, transformCoefs) => {
    const [varX, varY] = variation(x, y, transformCoefs);
    return [
      varX * coefs.a + varY * coefs.b + coefs.c,
      varX * coefs.d + varY * coefs.e + coefs.f,
    ];
  };
}

export const transform2Post = new TransformPost(
  transform2.coefs,
  [
    [1, linear],
    [1, popcorn],
  ],
  {
    a: 1,
    b: 0,
    c: 0.241352,
    d: 0,
    e: 1,
    f: 0.271521,
  }
);

export function renderPost(image: ImageData) {
  const flame = new Flame([
    [transform1Weight, transform1],
    [transform2Weight, transform2Post],
    [transform3Weight, transform3],
  ]);

  render(flame, 1, image);
}