// from https://codepen.io/tculda/pen/pogwpOw

sclass MultiPointGradient is MakesBufferedImage {

  LPair<IDoublePt, Color> gradientPoints;

  int w, h;

  int[] pixels;

  double[] gradientPointArray;

  Color[] colors;

  bool hasRun;

  *(LPair<IDoublePt, Color> *gradientPoints, int *w, int *h) {}

  *(WidthAndHeight size, LPair<IDoublePt, Color> *gradientPoints) {

    w = size.getWidth();

    h = size.getHeight();

  }

  *(int *w, int *h, LPair<IDoublePt, Color> *gradientPoints) {}

  public int getWidth() { ret w; }

  public int getHeight() { ret h; }

  public BufferedImage getBufferedImage() {

    run();

    ret intArrayToBufferedImageWithoutAlpha(pixels, w, h);

  }

  void init {

    if (pixels == null) pixels = new int[w*h];

    if (gradientPointArray == null)

      gradientPointArray = iDoublePtsToDoubleArray(pairsA(gradientPoints));

    if (colors == null)

      colors = toArray Color(pairsB(gradientPoints));

  }

  run {

    if (hasRun) ret;

    set hasRun;

    init();

    int n = l(colors);

    double[] colorRatios = new[n];

    int iPixel = 0;

    for y to h:

      for x to w: {

        fillArray(colorRatios, 1);

        for i to n:

          for j to n:

          if (i != j) {

            var d = getProjectionDistance2(

              gradientPointArray[i*2], gradientPointArray[i*2+1],

              gradientPointArray[j*2], gradientPointArray[j*2+1],

              x, y);

            colorRatios[i] *= clampZeroToOne(d);

          }

        pixels[iPixel++] = blendMultipleColorsToInt(colors, colorRatios);

      }

  }

}