[Paraview] What part of the pipeline is producing the request for UPDATE_EXTENT?

Mike Jackson imikejackson at gmail.com
Tue Feb 12 13:14:04 EST 2008

So I think I finally have this working.

In Request Information() I gather the actual full size extents of the  
data set (7000 x 8000 x 200). In the RequestData() method I get what  
the user actually wants (VOI), create a new vtkImageData based on VOI  
information, load the data into the new vtkImageObject, then do an  
output->ShallowCopy(image); just before the return of the RequestData  
Method. Do you see any drawbacks to using this type of approach?

This seems to work as the RequestData() method is only executing once  

The next thing I have to figure out is how to get some labels that  
tell the user just how large their data set it. Probably have to go  
with a Plugin with a custom Qt Panel at this point as I don't see any  
other way of doing it.

In PV 2.6 there used to be ways to get read only properties from a  
custom filter class and present those to the user. Doesn't seem like  
those facilities are there any more with PV 3.x

Thanks for the heads up.
Mike Jackson

On Feb 12, 2008, at 12:03 PM, Berk Geveci wrote:

> No. UPDATE_EXTENT() is set on the input information during
> RequestUpdateExtent(). A reader should NOT set UPDATE_EXTENT(). A
> reader should set WHOLE_EXTENT() in RequestInformation().
> -berk
> On 2/12/08, Mike Jackson <imikejackson at gmail.com> wrote:
>> I was under the impression that I needed to set the UPDATE_EXTENT
>> like the following in my RequestInformation() method:
>> outInfo->Set( vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(),  
>> this-
>>> DataExtent, 6 );
>> but I think that is a bad assumption for a reader. Is the ParaView
>> pipeline actually setting the UPDATE_EXTENT based on what it needs to
>> render?
>> --
>> Mike Jackson
>> imikejackson & gmail * com

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