[vtkusers] Set ImageData to zero

[Dominique Töpfer]

The best way I can think of, is writing a templated method SetToZero<T> 
and then perform the check for all possible types:

switch(pixelType)
{
case VTK_DOUBLE:
     SetToZero<double>(Image);
     break;
     ...
};

But maybe someone has a better idea...

On 28.09.2011 16:37, speedy wrote:
> I see. Do I have to check for every pixel type or is there a way to use the
> string directly?
> Something like:
>
> /const char* PixelType = Image->GetScalarTypeAsString();
> (PixelType)* PixelArray;
> PixelArray = ((PixelType)*)m_UserLabels->GetScalarPointer();
> /
>
> which obviously doesn't work.
>
>
> Dominique Töpfer wrote:
>> There are macros like VTK_DOUBLE defined in vtkTypes.h (
>> http://www.vtk.org/doc/nightly/html/vtkType_8h_source.html ). So you can
>> check the scalar type using
>>
>> if(Image->GetScalarType() == VTK_DOUBLE)
>>       // cast to double
>>
>> Of course, you can also GetScalarTypeAsString() as suggested by Jothy.
>>
>> HTH
>> Dominique
>>
>>
>> On 28.09.2011 15:21, speedy wrote:
>>> Thanks a lot for your reply Dominique!
>>> It is much faster indeed to use GetScalarPointer() instead of iterating
>>> through the pixels. I still have a problem though: My class doesn't know
>>> the
>>> pixeltype of the image beforehand, but I have to cast the pointer to it.
>>> How
>>> can I achieve this? I know there's the method
>>>
>>> Image->GetScalarType(),
>>>
>>> but it returns an integer value and I don't know how to proceed with it..
>>>
>>>
>>> Dominique Töpfer wrote:
>>>> Hi,
>>>>
>>>> a similar question was discussed here:
>>>> http://vtk.1045678.n5.nabble.com/Fast-element-access-of-vtkImageData-td4640137.html#none
>>>>
>>>> HTH
>>>> Dominique
>>>>
>>>> On 27.09.2011 15:47, speedy wrote:
>>>>> Sorry if this question actually has a simple answer, but what is the
>>>>> fastest
>>>>> way to set every pixel of a vtkImageData to zero (or any other value
>>>>> fitting
>>>>> in its pixeltype)?
>>>>> I've tried vtkImageThreshold, but it doesn't seem to do anything or
>>>>> maybe
>>>>> I
>>>>> am using it wrong:
>>>>>
>>>>>      threshold = vtkSmartPointer<vtkImageThreshold>::New();
>>>>>      threshold->SetInput(Image);
>>>>>      threshold->ReplaceOutOn();
>>>>>      threshold->SetOutValue(Value);
>>>>>      threshold->ThresholdByLower(maximum_image_value);
>>>>>      threshold->Update();
>>>>>
>>>>> --
>>>>> View this message in context:
>>>>> http://vtk.1045678.n5.nabble.com/Set-ImageData-to-zero-tp4845442p4845442.html
>>>>> Sent from the VTK - Users mailing list archive at Nabble.com.
>>>>> _______________________________________________
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>>>> -- 
>>>> Thus spake the master programmer:
>>>>        "After three days without programming, life becomes meaningless."
>>>>
>>>> -- The Tao of Programming by Geoffry James
>>>>
>>>> Dominique Töpfer, Dipl.-Inform.
>>>> Institute of Medical Physics
>>>> University of Erlangen
>>>>
>>>> _______________________________________________
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>>> --
>>> View this message in context:
>>> http://vtk.1045678.n5.nabble.com/Set-ImageData-to-zero-tp4845442p4849109.html
>>> Sent from the VTK - Users mailing list archive at Nabble.com.
>>> _______________________________________________
>>> Powered by www.kitware.com
>>>
>>> Visit other Kitware open-source projects at
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>>>
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>>
>> -- 
>> Thus spake the master programmer:
>>       "After three days without programming, life becomes meaningless."
>>
>> -- The Tao of Programming by Geoffry James
>>
>> Dominique Töpfer, Dipl.-Inform.
>> Institute of Medical Physics
>> University of Erlangen
>>
>> _______________________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>>
>> Please keep messages on-topic and check the VTK FAQ at:
>> http://www.vtk.org/Wiki/VTK_FAQ
>>
>> Follow this link to subscribe/unsubscribe:
>> http://www.vtk.org/mailman/listinfo/vtkusers
>>
>
> --
> View this message in context: http://vtk.1045678.n5.nabble.com/Set-ImageData-to-zero-tp4845442p4849412.html
> Sent from the VTK - Users mailing list archive at Nabble.com.
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at: http://www.vtk.org/Wiki/VTK_FAQ
>
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-- 
Thus spake the master programmer:
     "After three days without programming, life becomes meaningless."

-- The Tao of Programming by Geoffry James

Dominique Töpfer, Dipl.-Inform.
Institute of Medical Physics
University of Erlangen