Const correctness of PackedImageDesc

[jmather-sesi]

In our use case, we are passing const void pointers to build a source PackedImageDesc for use in CPUProcessor::apply. However, PackedImageDesc requires a non-const pointer. I assume this is so that users with non-const data can call getData and modify the result. This makes it dangerous to const_cast our pointer as a caller could then end up inadvertently modifying a const buffer through those calls.

Perhaps there should be a ConstPackedImageDesc? Or is the design to keep the scope of PackedImageDesc tightly around the apply call so that it's unlikely that users can access the getData functions?