#7 Saving and loading ROIs with handles

[vISTe]

When drawing ROIs using the middle mouse button, you get a polygon with a handle on each vertex. The advantage of these handles is that they can be moved individually, allowing the user to resize existing ROIs. However, when we save a ROI, we do not save these handles, nor can we load ROIs with handles.

Some thoughts:

The easiest way to store ROIs with handles would probably be using the VTK polydata format, which we already use for the ROIs. We could add a single scalar value per point of the ROI, which is 1 if the point is a handle, and 0 otherwise. The default polydata reader and writer will be able to process/handle these scalar arrays, making it easier to implement and making sure that ROIs without the 'handle' scalars are still usable.

The hardest part would probable be importing of a ROI with handles to the ROI drawing widget in such a way that the user will still be able to edit it.