Thank  you  for  your  reply. 
  
  
if the colors are FF0000 (Red), 00FF00 (Green), 0000FF (Blue),    FF0000   occupy 34% ( from  0  to 34),00FF00  occupy  34%( from 34 to 68)  ,0000FF occupy 32 % (from 68 to 100) 
  
the ratio  will be  "bgRatio='17,34,34' " 
  
17, the 1st starting point of the color Red. 
At this point, Red will be PURE Red. 
  
17+34=51, the 2st starting point of the color Green. 
At this point, Red will be PURE Green. 
  
17+34+34=85, the 3st starting point of the color Blue. 
At this point, Red will be PURE Blue. 
What I said is right?? 
  
Thank you very much for your reply  again.