ColorStripe and ColorDisc

Nice! For the disc, you could try something like:

  let yOffset = -Radius;
  setTimeout(function cb() {
    for (let xOffset = -Radius; xOffset <= Radius; xOffset++) {
      let OffsetSquared = xOffset*xOffset + yOffset*yOffset;
      if (OffsetSquared <= RadiusSquared) {
        let Hue        = Rad2Deg(Math.atan2(yOffset,xOffset));
        let Saturation = Math.sqrt(OffsetSquared)/Radius;
        let RGB        = HSVtoRGB(Hue, Saturation, Value);
        let Color = RGB[0] << 11 | RGB[1] << 5 | RGB[2];
        g.setPixel(Radius+xOffset,Radius+yOffset, Color);
      }
    }
    yOffset++;
    if (yOffset <= Radius)
      setTimeout(cb,10);
  },10);

To ensure that it doesn't 'hang' the browser while computing it :)