I am intersted in using Actors and Groups on a Stage so that I can make components and subcomponents which draw relative to their parents, but I intend to do my drawing with a ShapeRenderer instead of a Batch. From what I understand of an Actor, the batch which is passed in to the draw() method has all of its matrices set up properly so that I can just use a coordinate system WITHIN THE PARENT to lay out the subcomponents. But it seems that this coordinate system is focused on Batches, and I want to draw using a ShapeRenderer.
What do I have to do to get the child Actors to draw themselves RELATIVE TO THEIR PARENT (rather than in global coordinates) when drawing them with ShapeRenderers?
Also, one other question: How should I be managing begining/ending the ShapeRenderer? I am currently passing in a reference to a global ShapeRenderer when I construct my parent object, and this parent object passes in references to each of its children. Should I be calling begin() end() separately in the draw method of each parent/child actor? Or should I call it in my main app's draw() method, so I'm only calling it once each frame?