[Paraview] Image filters & extent

[Bryn Lloyd]

Another problem I get with the "partial solution" of setting the  
update extent in the output, is that the update extent is sent through  
the pipeline to the input. But it is too big for the input:

ERROR: In /Users/brynlloyd/pack/ParaView-CVS/VTK/Filtering/ 
vtkStreamingDemandDrivenPipeline.cxx, line 818
vtkCompositeDataPipeline (0x2183b5b0): The update extent specified in  
the information for output port 0 on algorithm  
vtkImageDataSource(0x2183b670) is 0 11 0 11 0 11, which is outside the  
whole extent 0 9 0 9 0 9.



On Mar 9, 2009, at 12:27 PM, Bryn Lloyd wrote:

> Hi,
>
> I have been having trouble with writing image filter plugins. If the  
> extent of the output image is larger than the input image extent, I  
> get all sorts of problems.
>
> I have tried using various parent classes, including  
> vtkImageAlgorithm. Currently I am using vtkDataSetAlgorithm (I  
> thought it would not try to be as "clever" as the vtkImageAlgorithm,  
> but it seems to be the same thing).
>
>
> 1. The full extent is not visualized:
> by setting the the extent of the output in RequestData I managed to  
> get the visualization right:
>
>  outInfo->Set( vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT(),  
> DataExtent, 6 );
>  outInfo->Set( vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(),  
> DataExtent, 6 );
>
>
> 2. Unfortunately, even with the addition above, the information  
> (extent, dimensions etc.) are not shown correctly in the  
> "Information tab" in paraview. Strangely enough, if I change a  
> parameter of the filter and call Apply a second time, the values in  
> the information tab are suddenly correct.
>
>
> What I want is really a simple way to generate an output image with  
> different size/extent than the input image, without having all this  
> trouble setting pipeline information. Is there a way?
>
> Thanks
> Bryn
>
>
>
>
>