[Paraview] Exposing BlendMode through UniformGridRepresentation (was: vtkSMProxy: GetSubProxy is protected, but I need it outside the class)

[Jérôme]

Hi,
thanks for your interest. Attached is a diff file between my rendering.xml
and CVS's one.
An idea to complete this would be to add a combo-box in the display panel
(such as the slider for slice representation,...). However, this is less
important, since when the BlendMode property is exposed through the
UniformGridRepresentation, the Comp. / MIP / MinIP rendering mode is
'toggleable'. Here is a code snippet that can be use in C++ from inside a
plugin to toggle BlendMode (Note, this could be more elegant by using
properly QList... ):

///////// Code-snippet: Toggle BlendMode
   pqViewManager * viewManager = qobject_cast<pqViewManager*>
         (pqApplicationCore::instance()->manager("MULTIVIEW_MANAGER"));

   // Get the representations present in the active view
   for( int repId = 0; repId < viewManager->getActiveView(
)->getNumberOfRepresentations( ); repId++)
   {

      pqRepresentation* rep = viewManager->getActiveView(
)->getRepresentation( repId );
      vtkSMUniformGridVolumeRepresentationProxy* proxy = 0;
      proxy =
static_cast<vtkSMUniformGridVolumeRepresentationProxy*>(rep->getProxy());

      // Check if the representation proxy is a
UniformGridVolumeRepresentationProxy
      if( proxy && rep->isVisible( ))
      {

         // Get the BlendMode property
         vtkSMIntVectorProperty* blendModeProp = 0;
         blendModeProp  = vtkSMIntVectorProperty::SafeDownCast(
proxy->GetProperty("BlendMode"));

         // If the Property is not exposed, it cannot be used!!
         if( blendModeProp )
         {
            // Increment the current BlendMode (Comp -> MIP ->MinIP ->Comp
->...
            int blendMode = blendModeProp->GetElement( 0 );
            blendMode++;
            blendModeProp->SetElement( 0, blendMode%3 );

            // Render
            proxy->UpdateSelfAndAllInputs( );
            rep->renderView( true );
         }
      }
   }

/////////////////// End Code-snippet: Toggle BlendMode

Thanks again,
Jerome


2009/10/19 Berk Geveci <berk.geveci at kitware.com>

> I don't have any problems with committing the changes you described.
> Would you mind adding a document element to the property XML though?
>
> -berk
>
> On Mon, Oct 19, 2009 at 10:50 AM, Jérôme <jerome.velut at gmail.com> wrote:
> > Thanks for your precisions.
> >
> > Well you are right! ParaView's proxy mechanism is robust and giving too
> much
> > freedom to developers could be really dangerous!
> > And effectively, my first try to have access to VolumeMapper BlendMode
> > property was to change the rendering.xml resource in order to expose it.
> >
> > What I did was:
> >
> > - adding a IntVectorProperty in FixedPointVolumeRayCastMapper SourceProxy
> >       <IntVectorProperty
> >         name="BlendMode"
> >         command="SetBlendMode"
> >         default_values="0"
> >         number_of_elements="1"
> >         animateable="0">
> >         <EnumerationDomain name="enum">
> >           <Entry value="0" text="Composite"/>
> >           <Entry value="1" text="MaximumIntensity"/>
> >           <Entry value="2" text="MinimumIntensity"/>
> >         </EnumerationDomain>
> >       </IntVectorProperty>
> >
> > - adding BlendMode as exposed property to
> > UniformGridVolumeRepresentationProxy in FixedPoint(...) SubProxy
> >           <Property name="BlendMode"/>
> >
> > - adding BlendMode as exposed property to UniformGridRepresentation
> > PVRepresentationProxy in UniformGrid(...) SubProxy.
> >
> > I changed blend mode by using GetProperty("BlendMode") on the
> representation
> > proxy, and it works as well. But in both case (bad unprotected way and
> > exposing propoerty way), I have to change something in ParaView's tree
> and
> > recompile it. It makes my plugin working on my computer only...
> >
> > Is this BlendMode exposure interesting you and do you want me to send a
> diff
> > file of my local 'rendering.xml'?
> >
> > Thanks again!
> >
> > Best regards,
> > Jerome
> >
> >
> >
> > 2009/10/19 Berk Geveci <berk.geveci at kitware.com>
> >>
> >> > - Is there a reason (software design, maybe?) to protect the functions
> >> > that
> >> > give access to subproxies, whereas the access to properties are
> >> > -fortunately- public?
> >> > - Is there another way to access SubProxy without modifying ParaView's
> >> > sources?
> >>
> >> Yes, there is a reason for not exposing the sub-proxies. We wanted the
> >> access to the sub-proxies to be only through exposed properties
> >> because we want all proxies (whether they have sub-proxies or not) to
> >> behave exactly the same way. Allowing access to the sub-proxies makes
> >> it almost impossible to make sure that developers don't shoot
> >> themselves in the foot by changing properties of the sub-proxies that
> >> are supposed to be controlled by the super-proxy. For example, a
> >> property in the super-proxy may end up setting multiple properties in
> >> the sub-proxy.
> >>
> >> Isn't there another way of doing this? Maybe expose the property you
> >> are setting? Something like VolumeMapperBlendMode?
> >>
> >> -berk
> >>
> >> On Mon, Oct 19, 2009 at 2:50 AM, Jérôme <jerome.velut at gmail.com> wrote:
> >> > Hi,
> >> >
> >> > I wrote a plugin that enable a toggle between different BlendMode of
> the
> >> > FixedPointVolumeRayCastMapper that is used by ParaView for volume
> >> > rendering.
> >> > It catches a key event on a render window ('B' pressed) and toggle
> >> > BlendMode: Composite -> MaximumIntensity -> MinimumIntensity ->
> >> > Composite->...
> >> >
> >> > Here is my way:
> >> > - When button 'B' pressed:
> >> >    - get view manager from core instance
> >> >    - get active view from view manager
> >> >    - for each representation 'rep' of active view:
> >> >       - check if 'rep' has a VolumeRepresentation SubProxy
> >> >       - if yes:
> >> >          - check if VolumeRepresentation has a
> >> > VolumeFixedPointRayCastMapper
> >> > SubProxy
> >> >          - if yes:
> >> >             - get the vtkFixedPointVolumeRayCastMapper ('mapper') from
> >> > this
> >> > latter SubProxy
> >> >             - mapper->SetBlendMode( (++mapper->GetBlendMode(  ))%3 );
> >> >             - Update and render.
> >> >
> >> >
> >> > For this to work, I need to call vtkSMProxy::GetSubProxy( char* ) from
> >> > my
> >> > plugin class. But unfortunately, these functions are protected member.
> I
> >> > modified the ParaView sources to make it public, and it work just...
> >> > fine.
> >> > My questions are:
> >> > - Is there a reason (software design, maybe?) to protect the functions
> >> > that
> >> > give access to subproxies, whereas the access to properties are
> >> > -fortunately- public?
> >> > - Is there another way to access SubProxy without modifying ParaView's
> >> > sources?
> >> >
> >> > Thanks!
> >> >
> >> > Jerome
> >> >
> >> > _______________________________________________
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>
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