constrain_int32_0_255
R = (uint8)constrain_int32_0_255((int32)(pow(linearR, 0.4) * 255.0 + 0.5));
G = (uint8)constrain_int32_0_255((int32)(pow(linearG, 0.4) * 255.0 + 0.5));
B = (uint8)constrain_int32_0_255((int32)(pow(linearB, 0.4) * 255.0 + 0.5));