ENH: Adding general hover support to rendered views.
- Using vtkHardwareSelector to capture the cell ids on the screen at any given time. This is reused as hover events occur. - Using vtkHoverWidget to receive timeout events when the mouse hasn't moved, and update the hover text then. - Added more functionality to vtkHardwareSelector to be able to query regions within the captured area (for drag selections) and being able to search out from a point to a given threshold distance for a cell (for hover text). - Added vertex and edge hovering to graph layout view, and edge hovering to tree area views.
Showing with 466 additions and 156 deletions