[vtkusers] Traversing (browsing) VTK pipeline

[David E DeMarle]

very nice thanks!

David E DeMarle
Kitware, Inc.
R&D Engineer
28 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-371-3971 x109



2010/8/31 Андрей Траченко <goodrone at gmail.com>:
> Thank you, David,
> your example helped me to find the API I was looking for.
>
> I've written a generic class in Python to browse the pipeline starting
> with vtkRenderer, and also a simple inherited class to show how to use
> it. I hope it could be useful for somebody.
>
> def iterate_collection(coll):
>    number = coll.GetNumberOfItems()
>    for i in xrange(number):
>        yield coll.GetItemAsObject(i)
>
> class PipelineBrowser(object):
>    """ Class for browsing a pipeline built using
>        x1.SetInputConnection(x2.GetOutputPort()) pattern.
>
>        Pass a vtkRenderer instance and call browse().
>        Inherit from this class and overwrite on_* methods.
>    """
>    def __init__(self, ren):
>        """ ren is a vtkRenderer """
>        self.ren = ren
>    def browse(self):
>        self.browse_renderer(self.ren)
>
>    def on_renderer(self, ren):
>        pass
>    def browse_renderer(self, ren):
>        self.on_renderer(ren)
>        for actor in iterate_collection(ren.GetActors()):
>            self.browse_actor(actor)
>
>    def on_actor(self, actor):
>        pass
>    def browse_actor(self, actor):
>        self.on_actor(actor)
>        self.browse_algorithm(actor.GetMapper(), 0, actor)
>
>    def on_algorithm(self, alg, level, parent):
>        pass
>    def browse_algorithm(self, alg, level, parent):
>        self.on_algorithm(alg, level, parent)
>        for port in range(alg.GetNumberOfInputPorts()):
>            for index in range(alg.GetNumberOfInputConnections(port)):
>                input_alg = alg.GetInputConnection(port, index).GetProducer()
>                self.browse_algorithm(input_alg, level + 1, alg)
>
> class PipelinePrinter(PipelineBrowser):
>    """ Simple pipeline browser, printing class names to stdout """
>    def on_renderer(self, ren):
>        print "Renderer:", ren.GetClassName()
>    def on_actor(self, actor):
>        print "  Actor:", actor.GetClassName()
>    def on_algorithm(self, alg, level, parent):
>        indent = " " * (level + 2) * 2
>        print indent + "Algorithm:", alg.GetClassName()
>
> Andrew
>
> 2010/8/31 David E DeMarle <dave.demarle at kitware.com>:
>> Here is some code I wrote long ago that runs up the pipeline to find
>> out who the progenitor was.
>>
>> void vtkStreamingUpdateSuppressor::PrintPipe(vtkAlgorithm *alg)
>> {
>>  //for debugging, this helps me understand which US is which in the messages
>>  vtkAlgorithm *algptr = alg;
>>  if (!algptr) return;
>>  if (algptr->GetNumberOfInputPorts() &&
>>      algptr->GetNumberOfInputConnections(0))
>>    {
>>    vtkAlgorithmOutput *ao = algptr->GetInputConnection(0,0);
>>    if (ao)
>>      {
>>      algptr = ao->GetProducer();
>>      this->PrintPipe(algptr);
>>      }
>>    cerr << "->";
>>    }
>>  cerr << alg->GetClassName();
>> }
>>
>> Note it only traces up the primary input so it doesn't handle merging,
>> and of course it is traversing only upward, so it doesn't handle
>> branching either.
>>
>> I've always meant to, but have not yet, put together a more complete
>> pipeline examiner. The API you need to do that should be found almost
>> exclusively in vtkExecutive and vtkAlgorithm.
>>
>> David E DeMarle
>> Kitware, Inc.
>> R&D Engineer
>> 28 Corporate Drive
>> Clifton Park, NY 12065-8662
>> Phone: 518-371-3971 x109
>>
>>
>>
>> 2010/8/27 Андрей Траченко <goodrone at gmail.com>:
>>> Another question of the same nature:
>>>
>>> given a vtkAlgorithm, can I tell what other algorithms are connected
>>> to it? I suspect I should use something like vtkExecutive, but I can't
>>> fugure out how.
>>>
>>> 2010/8/27 Андрей Траченко <goodrone at gmail.com>:
>>>> Hello,
>>>>
>>>> I'd like to browse a given VTK pipeline, where filters are connected
>>>> with a->SetInputConnection(b->GetOutputPort()), i.e. get a pointer to
>>>> every filter in the pipeline. Is it possible to do? Where do I start?
>>>> Can I browse it starting with a vtkRenderer?
>>>>
>>>> Thank you!
>>>> Andrew
>>>>
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>>
>