puLowerAvr
Pointer to an array containing the new average pixel value for those pixels with values between 0 and the average pixel value for the entire bitmap. The size of the array equals one, if uFlags is YUV_SPACE or GRAY_SPACE, or three, if uFlags is RGB_SPACE. If uFlags is RGB_SPACE the first element corresponds to the new blue lower average value, the second element to the green, and the last element to the red.