[Paraview] Reader Plugin Dev: "NA" extents & how to print debug messages?

[burlen]

Hi Peter,

To use the vtkDebugMacro, do a "this->DebugOn()" in your constructor.

You could just use cerr if you are Linux/mac and launch 
paraview/pvserver from a terminal.  Doing a "output->Print(cerr);" at 
the end of request data would prove that you did what you think.

You could use vtkErrorMacro to get stuff into PV 's window.

Burlen


Peter Schmitt wrote:
> Hi ParaViewers,
>
> (Sorry if this double-posts!)
>
> I am writing a ParaView Reader Plugin to get my data into ParaView via 
> a vtkStructuredGrid object.  I can load my plugin into ParaView via 
> "Manage Plugins".  My file type shows up in the "File-> Open" dialog. 
>  When PV_PLUGIN_DEBUG is set, the "Output Messages" window shows that 
> the library was loaded successfully.
>
> When I select a file and click "Apply" in the object inspector, 
> Paraview thinks for a split second before returning to an interactive 
> state.  However, no data appears & the "Information" tab of the object 
> inspector sets nCells = 0; nPoints = 0; Memory = 0 MB and the X,Y,Z 
> extents are "NA".
>
> My plugin reader derives from "vtkStructuredGridReader" and implements:
>
> * SetFileName
> * GetFileName
> * CanReadFile 
> * RequestInformation, where I set the extents via:
>   outInfo->Set(vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT(),extent,6);
> * RequestData, where I obtain a vtkStructuredGrid via:
>   vtkStructuredGrid *output =
>    
>  vtkStructuredGrid::SafeDownCast(outInfo->Get(vtkDataObject::DATA_OBJECT()));
>
> I am not sure why the "Information" tab is showing an empty structured 
> grid.  My questions are:
>
> 1.  How can I print debugging messages to stdout or Paraview's own 
> "Output Messages" window?  Specifically, I'd like to make sure that my 
> X,Y,Z extents are being read properly from file.   I tried 
> vtkDebugMacro, but the data isn't being printed.
>
> 2.  Have I implemented the appropriate functions that derive from 
> vtkStructuredGridReader?  
>
> 3.  Should I derive instead from another class?  When I derive from 
> vtkStructuredGridAlgorithm, I get three error messages from 
> vtkCompositeDataPipeline:  "Input port 0 of algorithm 
> vtkLFMReader(0x11f98a720) has 0 connections but is not optional".
>
> Can you offer any hints of how I can proceed to debug my reader?
>
> Thanks!
> Pete
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