[Paraview] Write a reader plugin

Mon Feb 7 13:31:58 EST 2011

Hi Utkarsh,
Then what is the purpose of RequestInformation()? I thought it is 
designed for handling large data set where the metadata can be extracted 
before loading the entire data set.
Best,
x

On 2/7/2011 1:29 PM, Utkarsh Ayachit wrote:
> Adriano,
>
> I don't believe the two are related. The "Information Tab" is not
> directly related to the information produced by the filter in
> "RequestInformation". The "Information tab" can be thought of as
> information from the dataset generated by the filter. Now the data is
> generated only after RequestData(), hence until RequestData() most
> information on the information-tab is empty.
>
> Utkarsh
>
> On Mon, Feb 7, 2011 at 10:34 AM, Adriano Gagliardi<agagliardi at ara.co.uk>  wrote:
>> Utkarsh,
>>
>> I believe some time ago I asked something similar regarding the having the
>> reader making a call to RequestInformation before actually hitting the Apply
>> button. Paul (Edwards) mentioned modifying the vtkGet/SetMacro to do this
>> automatically. I tried it briefly and I got something to compile, but it
>> didn't work and crashed out with segmentation fault.
>>
>> Is it possible, in both cases, to achieve this by modifying some of the
>> lower-level vtk code?
>>
>> Regards,
>>
>> Adriano
>>
>> ===================================
>>
>> Adriano Gagliardi MEng PhD
>> Business Sector Leader
>> Computational Aerodynamics
>> Aircraft Research Association Ltd.
>> Manton Lane
>> Bedford
>>
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>> -----Original Message-----
>> From: paraview-bounces at paraview.org [mailto:paraview-bounces at paraview.org]
>> On Behalf Of Utkarsh Ayachit
>> Sent: 07 February 2011 14:50
>> To: Xunlei Wu
>> Cc: paraview at paraview.org
>> Subject: Re: [Paraview] Write a reader plugin
>>
>> Xunlei,
>>
>> Are you expecting to see the extents setup correctly before hitting the
>> Apply button the first time? That indeed won't be the case. You'll have to
>> hit apply and let the actual data-reading happen before the information will
>> be shown on the "information tab".
>>
>> Utkarsh
>>
>> On Sat, Feb 5, 2011 at 5:46 PM, Xunlei Wu<xunlei at renci.org>  wrote:
>>> Hi David and All,
>>>
>>> I still have trouble seeing any updates in ParaView (ParaView Git built
>> from source with VS2008 and Qt 4.6.3 on Windows 7 64bit) after loading a
>> GRIB2 file. For simiplicity, I have created a skeleton version of my GRIB2
>> reader. I have only implemented RequestInformation() with some fabricated
>> WHOLE_EXTENT() data. I have successfully built such reader as a plugin .dll
>> (Windows) and loaded it into ParaView through Tool ->  Manage Plugins. After
>> you load a grib2 file also attached, RequestInformation() is called and
>> WHOLE_EXTENT() has been updated. However, I do not see such change in
>> "Object Inspector" ->  "Information" panel.
>>> I am not sure what I did wrong. And is there anything special I need to do
>> when build ParaView from source? FYI, "BUILD_SHARED_LIB" is on.
>>> Would you please help me? Thank you very much.
>>>
>>> Best,
>>> x
>>>
>>> -----Original Message-----
>>> From: Xunlei Wu
>>> Sent: Friday, January 21, 2011 12:10 PM
>>> To: David Doria
>>> Cc: paraview at paraview.org
>>> Subject: RE: Write a reader plugin
>>>
>>> Hi All,
>>> Do you have any suggestions? Thanks a lot.
>>> Best,
>>> xunlei
>>>
>>> -----Original Message-----
>>> From: Xunlei Wu
>>> Sent: Saturday, January 15, 2011 5:44 PM
>>> To: 'David Doria'
>>> Cc: 'paraview at paraview.org'
>>> Subject: Write a reader plugin
>>>
>>> Hi David and all,
>>> I am writing a reader plugin for ParaView. A test program without the
>>> VTK wrapping approves that I can get all the header (metadata) and
>>> grid data correctly. However, when I following the examples posted in
>>> http://www.vtk.org/Wiki/ParaView/Examples/Plugins/Reader
>>> http://www.kitware.com/products/html/WritingAParaViewReaderPlug-in.htm
>>> l
>>> and vtkStructuredGridReader.h/.cxx
>>>
>>> I got confused. Shall I subclass vtkStructuredGridAlgorithm or
>> vtkStructuredGridReader? What are the differences? With minor differences in
>> the code, i.e. defining char* FileName, I have both scenarios built fine.
>>> Let's say, we are subclassing vtkStructuredGridAlgorithm for now on.
>>> After I populate values as the following
>>>
>>> int vtkGRIB2Reader::RequestInformation(vtkInformation*
>>> vtkNotUsed(request),
>>> vtkInformationVector** vtkNotUsed(inputVector),
>>> vtkInformationVector *outputVector) {
>>>         ...
>>>         vtkInformation* outInfo =
>>> outputVector->GetInformationObject(0);
>>>
>>>         outInfo->Set(vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT(),
>>> ext, 6);
>>>         outInfo->Set(vtkDataObject::SPACING(),  this->Spacing, 3);
>>>         outInfo->Set(vtkDataObject::ORIGIN(),   this->Origin, 3);
>>>
>>>         return 1;
>>> }
>>>
>>> In ParaView Object Inspector / Information widget, I did not see any
>> update in all the fields except Statistics / Type: Structured (Curvilinear)
>> Grid. Would you please help me? Did I populate outInof in the wrong place?
>> Thanks a lot.
>>> Best,
>>> xunlei
>>>
>>>
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