[vtkusers] Strange behaviour of vtkXYPlotActor class

[Isidro Moreno]

Thanks John! Everything worked fine! Although I agree with you in the fact that it's easier to use data object rather than a dataset, I wondered If you could tell me why the SetDataObject...Component(... , ...) function doesn't work fine in my example and what's the difference between SetDataObjectPlotModeToColumns() and SetDataObjectPlotModeToRows(), since I don't know what columns and rows these functions refer to (I've already seen the HTML help).

Thanks again! Isidro.

----- Original Message ----- 
From: John Platt 
To: 'Isidro Moreno' 
Cc: vtk Users 
Sent: Thursday, December 13, 2007 7:39 PM
Subject: RE: [vtkusers] Strange behaviour of vtkXYPlotActor class


Hi,



It may be easier to use data object input rather than a data set. You could try the following.



#include "vtkFloatArray.h"

#include "vtkFieldData.h"

#include "vtkDataObject.h"

#include "vtkXYPlotActor.h"

#include "vtkXYPlotWidget.h"

#include "vtkMath.h"



#include "vtkRenderWindow.h"

#include "vtkRenderer.h"

#include "vtkRenderWindowInteractor.h"



int APIENTRY wWinMain(HINSTANCE hInstance,

                     HINSTANCE hPrevInstance,

                     LPSTR     lpCmdLine,

                     int       nCmdShow)

{

   vtkFloatArray* vtkXYValues = vtkFloatArray::New();

   vtkXYValues->SetNumberOfComponents( static_cast<vtkIdType>(2) );

   for ( int i = 0; i < 360; ++i )

   {

      float xy[2];

      xy[0] = static_cast<float>(i);

      xy[1] = sin( xy[0]*vtkMath::DegreesToRadians() );

      vtkXYValues->InsertNextTuple( xy );

   }



   vtkFieldData* vtkGraphFieldData = vtkFieldData::New();

   vtkGraphFieldData->AddArray( vtkXYValues );

   vtkXYValues->Delete();



   vtkDataObject* vtkGraphDataObject = vtkDataObject::New();

   vtkGraphDataObject->SetFieldData( vtkGraphFieldData );

   vtkGraphFieldData->Delete();



   vtkXYPlotActor* vtkGraph = vtkXYPlotActor::New();

   vtkGraph->AddDataObjectInput( vtkGraphDataObject );

   vtkGraphDataObject->Delete();



   vtkGraph->SetDataObjectPlotModeToColumns(); 

   vtkGraph->SetXValuesToValue();



   // Must state the component for the X & Y otherwise 0 is assumed for both!!

   int curve = 0;

   vtkGraph->SetDataObjectXComponent( curve, 0 );   

   vtkGraph->SetDataObjectYComponent( curve, 1 );



   vtkGraph->SetXRange( 0, 360 );

   vtkGraph->SetYRange( -1, 1 );

   vtkGraph->SetPlotColor( curve, 1,0,0 );



   vtkRenderer* renderer = vtkRenderer::New();

   renderer->AddActor2D( vtkGraph );



   vtkRenderWindow* renderWin = vtkRenderWindow::New();

   renderWin->AddRenderer( renderer );



   vtkRenderWindowInteractor* interactor = vtkRenderWindowInteractor::New();

   interactor->SetRenderWindow( renderWin );



   vtkXYPlotWidget* vtkXYPlotWidget = vtkXYPlotWidget::New(); 

   vtkXYPlotWidget->SetXYPlotActor( vtkGraph );

   vtkXYPlotWidget->SetInteractor( interactor );

   vtkXYPlotWidget->SetEnabled( true );



   interactor->Initialize();

   interactor->Start();



   return 0;

}



HTH John.



-----Original Message-----
From: vtkusers-bounces+jcplatt=dsl.pipex.com at vtk.org [mailto:vtkusers-bounces+jcplatt=dsl.pipex.com at vtk.org] On Behalf Of Isidro Moreno
Sent: 13 December 2007 18:37
To: vtkusers at vtk.org
Subject: [vtkusers] Strange behaviour of vtkXYPlotActor class



Hi! I'm a beginer in VTK and I've been trying to draw the sinus func with vtkxyplotactor for teaching purposes. The strange thing is that although I indicate which are the x-y components in the values array, the system draws the "arc sin" function. I don't know how to understand this; Am I wrong? or the system swap components?



Here's the code:



#include "vtkPointData.h"
#include "vtkPoints.h"
#include "vtkCellArray.h"
#include "vtkPolyData.h"
#include "vtkRenderer.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkXYPlotActor.h"
#include "vtkDataSetCollection.h"



int main(){



//  CONSOLE: how many points entry to form the "line".

//  CONSOLA: Ingreso de la cantidad de puntos que formarán la "curva".



    int data_puntos;
    cout<<"Ingrese cantidad de puntos (1-50): ";
    cin>>data_puntos;



//  Creación de una Celda - Definición topológica y geométrica



//  Definición Topológica
//  Inserción de 1(una) celda con 'n' puntos
    vtkCellArray *cellarray=vtkCellArray::New();
    cellarray->InsertNextCell(data_puntos);



//  Definición Geométrica y relación con la topología



    vtkPoints *puntos=vtkPoints::New();



    for(int j=0;j<data_puntos;j++){
        cellarray->InsertCellPoint(j); // ___ j = nºID de cada punto
        puntos->InsertPoint(
              j, // _________________________ nº ID
              j/5.0, // _____________________ valor de "x"
              sin(j/5.0), // ________________ valor de "y"
              0.0 // _________________________valor de "z"
              );}



//  Agregado de información topológica y geométrica al DataSet



    vtkPolyData *polydata=vtkPolyData::New();
    polydata->SetPoints(puntos);   // Puntos
    polydata->SetLines(cellarray); // Celdas - 1(una)



    polydata->GetPointData()->SetScalars(puntos->GetData());
    polydata->GetPointData()->Update();



//  Creación de un Actor



    vtkXYPlotActor *actor=vtkXYPlotActor::New();



    actor->SetXValuesToValue();
    actor->SetDataObjectXComponent(0,1);
    actor->SetDataObjectYComponent(0,2);



    actor->AddInput(polydata);
    

// The following didn't help me enough... : ( 

    cout<<endl
        <<"GetInputList()->GetNumberOfItems()="<<actor->GetInputList()->GetNumberOfItems()<<endl
        <<"GetDataObjectXComponent(0)="<<actor->GetDataObjectXComponent(0)<<endl
        <<"GetDataObjectYComponent(0)="<<actor->GetDataObjectYComponent(0)<<endl
        <<"GetXValues()="<<actor->GetXValues()<<endl
        <<"GetXValuesAsString()="<<actor->GetXValuesAsString()<<endl
        <<"GetPointComponent(0)="<<actor->GetPointComponent(0);



//  Creación de objetos de renderización



    vtkRenderer *renderer=vtkRenderer::New();
    renderer->AddActor2D(actor);
    renderer->SetBackground(0.0,0.0,0.0);



    vtkRenderWindow *ventana=vtkRenderWindow::New();
    ventana->AddRenderer(renderer);



    vtkRenderWindowInteractor *interac=vtkRenderWindowInteractor::New();
    interac->SetRenderWindow(ventana);



    ventana->Render(); // Inicio de la renderización
    interac->Initialize();
    interac->Start();  // Inicia el "looping"



    polydata->Delete();
    puntos->Delete();
    cellarray->Delete();
    actor->Delete();
    renderer->Delete();
    ventana->Delete();
    interac->Delete();



    return 0;}



Thanks in advance! Isidro.



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