We can cast the PixelFormat enum to int for the same information
and we can use the enum to reduce ambiguity when possible.
Change-Id: I6ea648139465568cdeb12e5f5f75c7b609365bf4
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/113188
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>