getting a part of a Canvas as a Bitmap

I'm trying to get a part of SurfaceView's canvas and save it as a Bitmap.
Every answer i've seen about it was creating a new Canvas and passing it your Bitmap to the constructor.

Because I am using SurfaceView, I am getting my canvas using the SurfaceHodler with mSurfaceHolder.lockCanvas(); thus i can't creat a new Canvas with my Bitmap.

How can I get a part of my canvas to a Bitmap without crating a new canvas?