how to do zooming algorithm

so ı was looking zooming algorithm and ı found this matlab code , but ı couldnt understand completely that part whis is marked on picture,please explain to me

Answer 1

[Image Analyst]

It's not even worth trying to understand. That code is junk.

Simply use imcrop() and imresize(),

or see the attached zooming demo.

[mts]

thank you for help.