For most pixels, in {HEAD ~ addition} to the reduction of the values of the component colors of the pixel , {TAIL ~ the alpha value} of the pixel will be reduced  
For most pixels , in { HEAD ~ addition } to the reduction of the values of the component colors of the pixel , { TAIL ~ the alpha value } of the pixel will be reduced
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH