Thank you , pook! I'm pleasure to see your post!
Firstly, for the function getHalfScale , we can only zoom out the bitmap by many pixel operations. I think it may be adding too much compute process comparing with setScale(), of course it's maybe!
Secondly, if we want to zoom in the image, we need to write another image processing algorithm. And obviously , the algorithm of getting the average value of a n*n area is not the best way.
So I think using the system method setScale() maybe is a better way! And I want to change the bitmap b into EncodeImage , how can I do this?
Thank you again for your help!