The compositor assumes the entire viewport as its compositing space even
in camera view. The current design decision was to limit the compositing
space by the camera region only if the camera passepartout is opaque,
that is, areas outside of the camera are not visible.
This patch changes that behavior to always limit the compositing space
by the camera region. The downside is that areas outside of the camera
will be left uncomposited.
This is useful to match viewport compositing to final render compositing
in terms of maintaining the same space, but not necessarily the same
resolution. However, this still has the limitation that space will be
different when the camera region intersects the viewport, since we only
composite their intersection in that case.
Pull Request: https://projects.blender.org/blender/blender/pulls/118241
49faea5f36