[vtkusers] vtkBlend Output

David Gobbi david.gobbi at gmail.com
Fri Nov 5 11:38:51 EDT 2010 

Well, Alexis, how about at least you do an informal review of the API?

It looks like VTK development isn't the wild west anymore.  Things are
starting to get civilized around here.

  David


On Fri, Nov 5, 2010 at 9:02 AM, Bill Lorensen <bill.lorensen at gmail.com> wrote:
> David,
>
> Going forward, I think a gerrit review of new classes is a good idea.
> http://review.source.kitware.com/#q,status:open,n,z
>
> It is good to have another set of eyes critique the API. Also, it will
> ensure that a corresponding test is added (I see that you added
> tests).
>
> A new user should not depend on an API that has not passed some sort
> of review process.
>
> Bill
>
>
> On Thu, Nov 4, 2010 at 3:01 PM, David Gobbi <david.gobbi at gmail.com> wrote:
>> They're available now.  I sidestepped the review process because these
>> classes don't touch any critical bits of VTK code.  Opinions, however,
>> are always welcome.
>>
>>  David
>>
>> On Thu, Nov 4, 2010 at 12:48 PM, Alexis Cheng <acheng_1221 at hotmail.com> wrote:
>>> Hi David,
>>>
>>> Just to clarify, are these 2 classes available right now or is there a
>>> review process?
>>>
>>> Thanks,
>>> Alexis Cheng
>>> Electrical Engineering
>>> University of British Columbia
>>>
>>>> From: david.gobbi at gmail.com
>>>> Date: Thu, 4 Nov 2010 07:57:11 -0600
>>>> Subject: Re: [vtkusers] vtkBlend Output
>>>> To: acheng_1221 at hotmail.com
>>>> CC: vtkusers at vtk.org
>>>>
>>>> I've just committed two new classes for generating stencils:
>>>> 1) Imaging/vtkROIStencilSource - rectangles and ellipses
>>>> 2) Imaging/vtkLassooStencilSource - polygons and splines
>>>>
>>>> David
>>>>
>>>> On Wed, Nov 3, 2010 at 8:52 AM, David Gobbi <david.gobbi at gmail.com> wrote:
>>>> > Hi Alexis,
>>>> >
>>>> > The PolyDataToImageStencil filter requires a closed 3D polydata
>>>> > surface, like a box or a sphere.  It does not work with 2D contours.
>>>> >
>>>> > I have a "lassoo" class based on some of my old python code for doing
>>>> > ROI stencils, but it is incomplete.  It would work like
>>>> > ImplicitSelectionLoop for vtkImageStencilData, but a few hundred times
>>>> > faster.  I'll take a look at it today to see how much work it would be
>>>> > to finish it and contribute it to VTK.
>>>> >
>>>> >  David
>>>> >
>>>> > On Tue, Nov 2, 2010 at 6:07 PM, Alexis Cheng <acheng_1221 at hotmail.com>
>>>> > wrote:
>>>> >> Hi David,
>>>> >>
>>>> >> It certainly seems to be the Stencil filter that is slowing the system
>>>> >> down.
>>>> >> I am trying to use vtkPolyDataToImageStencil to see if that would be
>>>> >> any
>>>> >> faster, but I'm having some difficulties.
>>>> >>
>>>> >> I replaced this ImplicitFunction code:
>>>> >>
>>>> >>         vtkSmartPointer<vtkImplicitSelectionLoop> ImplicitLoop =
>>>> >> vtkSmartPointer<vtkImplicitSelectionLoop>::New();
>>>> >>         ImplicitLoop->SetLoop(points);
>>>> >>
>>>> >>         vtkSmartPointer<vtkImplicitFunctionToImageStencil>
>>>> >> dataToStencil =
>>>> >> vtkSmartPointer<vtkImplicitFunctionToImageStencil>::New();
>>>> >>         dataToStencil->SetInput(ImplicitLoop);
>>>> >>
>>>> >> with this PolyData code:
>>>> >>
>>>> >>         vtkSmartPointer<vtkCellArray> polygons =
>>>> >> vtkSmartPointer<vtkCellArray>::New();
>>>> >>         vtkSmartPointer<vtkPolygon> polygon =
>>>> >> vtkSmartPointer<vtkPolygon>::New();
>>>> >>         polygon->GetPointIds()->SetNumberOfIds(4); //make a quad
>>>> >>         polygon->GetPointIds()->SetId(0, 0);
>>>> >>         polygon->GetPointIds()->SetId(1, 1);
>>>> >>         polygon->GetPointIds()->SetId(2, 2);
>>>> >>         polygon->GetPointIds()->SetId(3, 3);
>>>> >>
>>>> >>         polygons->InsertNextCell(polygon);
>>>> >>
>>>> >>         vtkSmartPointer<vtkPolyData> quad =
>>>> >> vtkSmartPointer<vtkPolyData>::New();
>>>> >>         quad->SetPoints(points);
>>>> >>         quad->SetPolys(polygons);
>>>> >>
>>>> >>         vtkSmartPointer<vtkPolyDataToImageStencil> dataToStencil =
>>>> >> vtkSmartPointer<vtkPolyDataToImageStencil>::New();
>>>> >>         dataToStencil->SetInput(quad);
>>>> >>
>>>> >> The final image does not show the stencil with the PolyData code. Is
>>>> >> there a
>>>> >> difference in the implementation of the 2 filters where I would have a
>>>> >> different output or need a different input? Also, should I expect to
>>>> >> see any
>>>> >> increase in performance by using PolyData instead of ImplicitFunction?
>>>> >> Thanks for all your answers!
>>>> >>
>>>> >> Cheers,
>>>> >> Alexis Cheng
>>>> >> Electrical Engineering
>>>> >> University of British Columbia
>>>> >>
>>>> >>
>>>> >>
>>>> >>> From: david.gobbi at gmail.com
>>>> >>> Date: Mon, 1 Nov 2010 19:27:40 -0600
>>>> >>> Subject: Re: [vtkusers] vtkBlend Output
>>>> >>> To: acheng_1221 at hotmail.com
>>>> >>> CC: vtkusers at vtk.org
>>>> >>>
>>>> >>> Hi Alexis,
>>>> >>>
>>>> >>> Have you tried it without the stencil, for comparison? The
>>>> >>> vtkImplicitFunctionToImageStencil filter is very slow.
>>>> >>>
>>>> >>> David
>>>> >>>
>>>> >>>
>>>> >>> On Mon, Nov 1, 2010 at 5:57 PM, Alexis Cheng <acheng_1221 at hotmail.com>
>>>> >>> wrote:
>>>> >>> > Hi all,
>>>> >>> >
>>>> >>> > Is vtkBlend extremely resource intensive? I have a following piece
>>>> >>> > of
>>>> >>> > code
>>>> >>> > running: FinalImage is a vtkImageData object, MTImage is a
>>>> >>> > vtkImageData
>>>> >>> > object, and blend1 is a vtkImageBlend object.
>>>> >>> >
>>>> >>> >         blend1->SetStencil(dataToStencil->GetOutput());
>>>> >>> >         blend1->AddInput(MTImage);
>>>> >>> >         blend1->AddInput(BlackImage);
>>>> >>> >         blend1->SetOpacity(0,0.5);
>>>> >>> >         blend1->SetOpacity(1,0.5);
>>>> >>> >
>>>> >>> >         if(OutOfView)
>>>> >>> >         {
>>>> >>> >             FinalImage = MTImage;
>>>> >>> >         }
>>>> >>> >         else
>>>> >>> >         {
>>>> >>> >             FinalImage = blend1->GetOutput();
>>>> >>> >         }
>>>> >>> >         FinalImage->Update();
>>>> >>> >
>>>> >>> > The fps of my display decreases dramatically whenever the output
>>>> >>> > from
>>>> >>> > blend
>>>> >>> > is requested. Is this behaviour expected? Thanks in advance.
>>>> >>> >
>>>> >>> > Cheers,
>>>> >>> > Alexis Cheng
>>>> >>> > Electrical Engineering
>>>> >>> > University of British Columbia
>>>> >>> >
>>>> >>> > _______________________________________________
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>>>> >>> >
>>>> >>
>>>> >
>>>
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>> _______________________________________________
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>>
>> Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html
>>
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