I'm trying to get the extends of all visible items on a drawing (annotations, model edges, sketch lines, etc)  I've found api for: View Position, View Outline.  I know I can get the coordinates of most (all???) annotations using the GetPosition method.  However, I'm not really sure how to go about this.  So really I'm looking to get a Xmin, Xmax, Ymin, Ymax that would be like a zoom to fit of just the visible items.

Anyone have any ideas how to get these values?