code: func AdjustGamma(img image.Image, gamma float64) *image.NRGBA {
  	e := 1.0 / math.Max(gamma, 0.0001)
  	lut := make([]uint8, 256)
  
  	for i := 0; i < 256; i++ {
  		lut[i] = clamp(math.Pow(float64(i)/255.0, e) * 255.0)
  	}
  
  	return adjustLUT(img, lut)
  }
docs: // AdjustGamma performs a gamma correction on the image and returns the adjusted image.
  // Gamma parameter must be positive. Gamma = 1.0 gives the original image.
  // Gamma less than 1.0 darkens the image and gamma greater than 1.0 lightens it.
  //
  // Example:
  //
  //	dstImage = imaging.AdjustGamma(srcImage, 0.7)
  //