customize location and shape of a new window in a frame

["Roland Winkler" <winkler@gnu.org>]

Someone posted this on the BBDB mailing list

http://lists.nongnu.org/archive/html/bbdb-user/2018-09/msg00031.html

But the question is quite generic, and I guess it must be an issue
for other packages, too:

BBDB wants to pop-up a window in a frame that already has multiple
windows.  Different users like to do this in different ways and
split an existing window vertically or horizontally, giving a
customizable percentage of screen estate to the new window.

Is there a general function that BBDB could use here, a function
that users can customize for their needs?

Currently, BBDB uses the function bbdb-pop-up-window for this, which
already provides some flexibility.  I could try to tweak this
function as described in the above request.  But it seems to me that
I might reinvent the wheel.  There should be general code for this
that BBDB could use.

Am I missing something?

Roland