[vtkusers] Tree Depth First Traversal Animation

[David Doria]

On Wed, Apr 7, 2010 at 9:42 AM, Jeff Baumes <jeff.baumes at kitware.com> wrote:
> On Sat, Apr 3, 2010 at 2:45 PM, David Doria <daviddoria+vtk at gmail.com> wrote:
>> I am trying to make a demo of a depth first traversal of a graph.
>> http://www.vtk.org/Wiki/VTK/Examples/Graph/DFSAnimation
>> The idea is to start with a tree of red vertices, and color the next vertex
>> in the traversal blue every 1 second. It almost works - the vertices change
>> color if you interact with the window (i.e. click the mouse). I thought the
>> couple of calls to Render() at the end of the timer callback would have
>> refreshed the window automatically?
>
> Try adding
>
> this->Tree->Modified();
>
> after your SetValue() call. For efficiency, SetValue() does nothing
> other than change the raw array data, so does not mark the array (and
> hence the tree) modified, so the pipeline will not update upon
> rendering. To render, you should just do
>
> this->GraphLayoutView->Render();
>
>> Also, the vertices all return to red
>> after the last vertex is reached?
>
> The colors go back to all red because all vertices have the same
> value. The color map automatically scales to the range of the data. To
> use the range in the lookup table, do:
>
> theme->ScalePointLookupTableOff();
>
> Jeff
>

Perfect, everything you said was spot on. Thanks a lot, Jeff.

David