Docker digest questions

As I test, pull one image from docker hub, and then push to my private registry_A.
then I check the manifest from docker hub and from my private registry,
the layer digest is different.

so, same content in different registry will has the different digest?

then calculate or check the digest, does the registry domain is the input paramters?
in different docker registry, same content’s digest will be same or not same?

but I create another private registry_B and push the same image to the registry_B,
and then check the mainifest.
the layer digest from registry_A and registry_B is same.

I am so confused