docs: public void mutate(float amount) {
  		for (int i = 0; i < numKnots; i++) {
  			int rgb = yKnots[i];
  			int r = ((rgb >> 16) & 0xff);
  			int g = ((rgb >> 8) & 0xff);
  			int b = (rgb & 0xff);
  			r = PixelUtils.clamp( (int)(r + amount * 255 * (Math.random()-0.5)) );
  			g = PixelUtils.clamp( (int)(g + amount * 255 * (Math.random()-0.5)) );
  			b = PixelUtils.clamp( (int)(b + amount * 255 * (Math.random()-0.5)) );
  			yKnots[i] = 0xff000000 | (r << 16) | (g << 8) | b;
  			knotTypes[i] = RGB|SPLINE;
  		}
  		sortKnots();
  		rebuildGradient();
  	}