[Paraview-developers] Get data from server to client (helper?)

[Biddiscombe, John A.]

Thanks utkarsh, the problem was at our end with a couple of bugs in the PVInformation class which caused problems. The RootOnly flag wasn't being overridden as intended and there wer also bugs in our stream insertion stuff, however, I now have histograms for pvservers appearing in the transfer function editors on the gui. All is well

Many thanks as usual

JB

> -----Original Message-----
> From: Utkarsh Ayachit [mailto:utkarsh.ayachit at kitware.com]
> Sent: 22 October 2013 18:36
> To: Biddiscombe, John A.
> Cc: paraview-developers at paraview.org
> Subject: Re: [Paraview-developers] Get data from server to client (helper?)
> 
> John,
> 
> I cannot reproduce the problem. Try the attached patch. With that, I have
> added code to do GatherInformation() on a representation when it's
> deleted. Try this:
> 
> + Create Sphere
> + Apply
> + Delete Sphere
> 
> You'll see an output on the terminal when CopyFromObject is called. In
> built-in mode, I see the output on the client, while in client-server mode, I
> only see it on the server, as expected.
> 
> Utkarsh
> 
> On Tue, Oct 22, 2013 at 12:25 PM, Utkarsh Ayachit
> <utkarsh.ayachit at kitware.com> wrote:
> > I don;t see anything wrong with what you're doing. Let me try it out
> > to see if there's something broken/missing.
> >
> > Utkarsh
> >
> > On Tue, Oct 22, 2013 at 12:17 PM, Biddiscombe, John A. <biddisco at cscs.ch>
> wrote:
> >> Utkarsh
> >>
> >>> Create a new vtkPVInformation subclass with following points to note:
> >>>
> >>> + Override GetRootOnly() to return 1. Thus ParaView will only gather
> >>> the information from the root node.
> >>> + Override CopyFromObject() to downcast to right type and call which
> >>> every method you want to get the data
> >>> + Override CopyToStream and CopyFromStream to serialize the data
> >>> collected in CopyFromObject to/from a client-server stream.
> >>> + AddInformation() is used to reduce the results in parallel. Since
> >>> you don't need that, I believe you can leave that empty.
> >>>
> >>> Now, in your client code, to fetch the data you can do something as
> follows:
> >>>
> >>> vtkNew<vtkMyNewInformationClass> instance;
> >>> repr->getProxy()->GatherInformation(instance.GetPointer())
> >>
> >> When we do this, the GatherInformation call is executing on the client.
> I've experimented with
> >>   repr->getProxy()->GatherInformation(info.GetPointer(),
> >> vtkPVSession::RENDER_SERVER); but the CopyFromObject() call inside
> the information is copying on the client, and so results are wrong. I had
> assumed it would CopyFromObject on the root node of the server, and then
> CopyToStream and on the client do a CopyDromStream.
> >>
> >> Is there another step I need perhaps to trigger it to do this the way I
> expect?
> >>
> >> thanks
> >>
> >> JB