[IGSTK-Developers] FourViewsTrackingWithCT Application

[Luis Ibanez]

Hi Patrick,

Just for the sake of clarity, we should differentiate between
the "Viewer", that is the "View2D" and "View3D" classes and
the ImageSpatialObjectRepresentation, or in general the
SpatialObjectRepresentations.

The "Picking" operation is not really something to be implemented
in the Viewer, but into the SpatialObjectRepresentation, because
you could imagine multiple images being visible in the same scene,
along with geometrical objects that are represented by Spatial
Objects.

Probably the right way to implement picking will be as a functionality
of the representation classes, and by throwing an Event containing the
3D physical coordinates of the Picked point. In this way, an application
developer will be able to connect an observer to the object where the
user is expected to pick, and cumulate those picked points to be used
by the application later on.

IGSTK events can have cargo information, e.g. we have one that can
transmit a transform, we could add one that carries a position in space.


We probably should sketch some requirements regarding picking.

Note that one of the issues in VTK with picking is how it should
behave when you have overlapping objects. In general a use would expect
to pick from the object that is closer to the camera, but that is not
the default VTK behavior.



    Luis


--------------------
Patrick Cheng wrote:
> Hi everyone,
> 
> I guess we start coding for the iteration 6 now. As the new application 
> is largely depends on the Viewer, ImageIO, ImageSpatialObject, and 
> ImageSpatialObjectRepresentation, and there are not quite ready yet. So 
> I am thinking if I can take over some tasks.
> 
> For the iteration 6, I am also thinking shall we put the 'pick' feature 
> into the Viewer? I need it in the application to set the landmarks in 
> the image. It will be nice to have the text spatial object ready too (to 
> mark different points).
> 
> A another open question: Do your guys think it's useful to add an 
> igstkSpatialObject Reader and Writer? I think it will save some efforts 
> for the application developer, especially when more complicated or 
> assambled spatial object is being used.
> 
> Cheers,
> 
> Patrick
>