[vtkusers] OK so does ANYONE use the vtkImageTracerWidget?

[Mark Wyszomierski]

Ok I put up an example here if anyone needs it:

    http://devsample.org/index.php?option=com_content&task=view&id=50&Itemid=27

It'll load up an image volume (from a set of DICOM files), you can
scroll through them and draw enclosures on each slice. When you scroll
to previous slices, the widget will reinitialize itself to make it
look like it's saving your enclosures per slice. This is what I've
seen done in a few different software packages.

Mark



On 11/5/07, kent williams <nkwmailinglists at gmail.com> wrote:
> I have the opposite issue with int/reinit of handles. I'd like to be
> able to turn on all the handles for all the points once a curve is
> closed ;-)
>
>
> On 11/5/07, Mark Wyszomierski <markww at gmail.com> wrote:
> > Dean,
> >
> > I worked with this a bit more, I have two questions if you have time:
> >
> > 1) Right now after the enclosure is drawn, I am storing all the points using:
> >
> >         GetPath(vtkPolyData);
> >
> > When trying to restore the points of the enclosure later on, there
> > doesn't seem to be any 'SetPath()' function, we have to use
> > InitializeHandles(). The problem is that there may be hundreds of
> > points that make up an enclosure, and now all of them will be turned
> > into handles which can be really slow. For instance, if you just draw
> > a free-hand enclosure, there's only one handle. I can't find a way to
> > restore that enclosure with one handle but many non-handle points.
> >
> > 2) To initialize a 'NULL' enclosure, it looks like we need to push on
> > at least two dummy points, otherwise the line connection code isn't
> > generated. For now I'm doing:
> >
> >         p->InsertNextPoint(0, 0, 0);
> >         p->InsertNextPoint(0, 0, 0);
> >
> > I checked the condition inside InitializeHandles() and it seems at
> > least two handles are necessary (otherwise previous line geometry
> > isn't reset).
> >
> > After you suggested SetProjectionPosition(), my example is working as
> > expected, I will post it if anyone is still interested. The widget is
> > great, just wondering if there's some way around #1 to speed it up a
> > little,
> >
> > Thanks,
> > Mark
> >
> >
> >
> > On 11/5/07, Dean Inglis <dean.inglis at sympatico.ca> wrote:
> > > A couple of points on using vtkImageTracerWidget:
> > >
> > > 1) InitializeHandles requires that the vtkPoints be non-NULL
> > > and that there be n>0 points
> > > 2) if you change the slice position, then you have to
> > > tell the widget where you want to place points onto:
> > > (e.g. from Examples/GUI/Tcl/ImageTracerwidget.tcl)
> > >  itw ProjectToPlaneOn
> > >  itw SetProjectionNormalToXAxes
> > >  itw SetProjectionPosition $pos
> > >
> > > If you just change the slice position using vtkImageActor
> > > to view slices in a volume and not the slice
> > > orientation, then SetProjectionPosition will update
> > > the coordinates of all the handles of the widget.
> > >
> > > Kent, as for your current problem:
> > >
> > > >What isn't happening right now: If I switch to an untraced slice, I
> > > >call InitializeHandles() with a zero length set of points, but this
> > > >doesn't in fact get rid of the currently visualized trace.
> > >
> > > I didn't design the tracer to work this way, but if you
> > > want a work-around for now, just send in a vtkPoints
> > > with one point with coords of the center of the current
> > > image slice.  This should show one handle signifying
> > > to the user to start tracing.  e.g.:
> > >
> > > vtkPoints* pt = vtkPoints::New();
> > > pt->InsertNextPoint(0,0,0);
> > > // set the widget to have one handle
> > > widget->InitializeHandles(pt);
> > > // this should force the first handle to lie at the center of
> > > // the bounds of the image plane
> > > widget->PlaceWidget(myImageActor->GetBounds());
> > > // if the slices are x-y planes
> > > widget->SetProjectionPosition(myImageActor->GetBounds()[4]);
> > >
> > >
> > > Another option would be to use the latest cvs
> > > vtkContourWidget since I recently
> > > modified it to take a NULL vtkPolyData in to Initialize
> > > the widget to its starting state. You can draw with either
> > > straight line segments between placed handles or
> > > have it interpolate a higher order curve between them.
> > > vtkCntourWidgte will not let you "trace" continuously though.
> > >
> > > HTH,
> > > Dean
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