Snapshots a cross-fade operation between two images with the
given @progress.
Until the first call to [method@Gtk.Snapshot.pop], the start image
will be snapshot. After that call, the end image will be recorded
until the second call to [method@Gtk.Snapshot.pop].
Calling this function requires two subsequent calls
to [method@Gtk.Snapshot.pop].
Snapshots a cross-fade operation between two images with the given @progress.
Until the first call to [method@Gtk.Snapshot.pop], the start image will be snapshot. After that call, the end image will be recorded until the second call to [method@Gtk.Snapshot.pop].
Calling this function requires two subsequent calls to [method@Gtk.Snapshot.pop].