[vtkusers] Writing a JPEG from vtkActor

[Dominik Szczerba]

It doesnt help. The image is empty :( I tried both versions 4.4.2 and CVS...
--dsz

> I just realized I did the division backwards in this step.  You should
> be dividing 256 by the difference in the minimum and maximum range values.
> 
> iss->SetScale(256.0 / (range[1] - range[0]));
> 
> 
>>   vtkPNGWriter* writer = vtkPNGWriter::New();
>>   writer->SetInput(iss->GetOutput());
>>   writer->SetFileName(argv[2]);
>>   writer->Write();
>>
>> Always the first scalar is taken, regardles of explicit selection with
>> setActiveScalarrs. The info seems displayed properly (of the first
>> scalar) whih is in my case -9.11732e-06 1.53533e-05, output is black
>> image (empty histogram).
>> I will be grateful if you shed some light on this mystery.
>> Dominik
>>
>> Amy Squillacote wrote:
>> > Try using vtkImageShiftScale instead.  Do something like the following.
>> >
>> > double range[2];
>> > grid->GetCellData()->GetScalars("abc")->GetScalarRange(range);
>> >
>> > vtkImageShiftScale *iss = vtkImageShiftScale::New();
>> > iss->SetInput(grid);
>> > iss->SetOutputScalarTypeToUnsignedChar();
>> > iss->SetShift(-range[0]);
>> > iss->SetScale((range[1] - range[0]) / 256.0);
>> >
>> > Are you sure that the data in your grid (a vtkImageData, I assume)
>> is in
>> > cell data? It's usually in point data.
>> >
>> > - Amy
>> >
>> > At 09:44 AM 12/20/2005, Dominik Szczerba wrote:
>> >
>> >> Thanks a lot, yes, I am trying the vtkImageCast, compiles fine, but
>> get
>> >> a black image at the end. Shouldnt I set ranges somewhere?
>> >> I can do
>> >>
>> >> grid->GetCellData()->GetScalars("abc")->GetRange())
>> >>
>> >> but where do I plug the output?
>> >>
>> >> Dominik
>> >>
>> >> Amy Squillacote wrote:
>> >> > Try using either vtkImageCast or vtkImageShiftScale to change your
>> >> image
>> >> > data to contain either unsigned char or unsigned short data.
>> >> >
>> >> > - Amy
>> >> >
>> >> > At 08:58 AM 12/20/2005, Dominik Szczerba wrote:
>> >> >
>> >> >> What is the error? I try to do the same with vtkPNGWriter ending up
>> >> with:
>> >> >>
>> >> >> vtkPNGWriter (0x8058948): PNGWriter only supports unsigned char and
>> >> >> unsigned short inputs
>> >> >>
>> >> >> Meanwhile I try to figure out how to do the appropriate
>> convertion in
>> >> >> vtk.
>> >> >> --dsz
>> >> >>
>> >> >> Marlos Fabris wrote:
>> >> >> > Hi,
>> >> >> >
>> >> >> > I'm trying to write a jpeg file (using vtkJPEGWriter) from a
>> >> vtkActor
>> >> >> > but I can't accomplish this. I have a vtk file with structured
>> >> points
>> >> >> > data and I wish to transform to vtkPolyData and color it with my
>> >> >> > vtkLookupTable.
>> >> >> >
>> >> >> > Is there a way to convert only my vtkActor to a vtkImageData,
>> >> without
>> >> >> > the frameborders of vtkWindowToImageFilter?
>> >> >> >
>> >> >> > Or is there a way to trim my image?
>> >> >> >
>> >> >> > Thank you in advance,
>> >> >> >
>> >> >> > Marlos Fabris
>> >> >> > _______________________________________________
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>> >> >>
>> >> >> --
>> >> >> Dominik Szczerba, Dr.
>> >> >> ETZ C110 CO-ME/BIWI CH-8092 Zurich
>> >> >> http://www.vision.ee.ethz.ch/~domi
>> >> >> _______________________________________________
>> >> >> This is the private VTK discussion list.
>> >> >> Please keep messages on-topic. Check the FAQ at:
>> >> >> http://www.vtk.org/Wiki/VTK_FAQ
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>> >>
>> >> --
>> >> Dominik Szczerba, Dr.
>> >> ETZ C110 CO-ME/BIWI CH-8092 Zurich
>> >> http://www.vision.ee.ethz.ch/~domi
>> >> _______________________________________________
>> >> This is the private VTK discussion list.
>> >> Please keep messages on-topic. Check the FAQ at:
>> >> http://www.vtk.org/Wiki/VTK_FAQ
>> >> Follow this link to subscribe/unsubscribe:
>> >> http://www.vtk.org/mailman/listinfo/vtkusers
>>
>> -- 
>> Dominik Szczerba, Dr.
>> ETZ C110 CO-ME/BIWI CH-8092 Zurich
>> http://www.vision.ee.ethz.ch/~domi
>> _______________________________________________
>> This is the private VTK discussion list.
>> Please keep messages on-topic. Check the FAQ at:
>> http://www.vtk.org/Wiki/VTK_FAQ
>> Follow this link to subscribe/unsubscribe:
>> http://www.vtk.org/mailman/listinfo/vtkusers

-- 
Dominik Szczerba, Dr.
ETZ C110 CO-ME/BIWI CH-8092 Zurich
http://www.vision.ee.ethz.ch/~domi