Histogram with Selection Callback

Input : Jpeg Image

Commands:
Left Click will Draw the rectangle and select the cell enclosed.
Right Click will Draw the rectangle and zoom the cells enclosed.

Steps to build:

• Create Folder name ChartTest keep below files in it.
• Create QChartwithInteraction.cpp and copy the below code
• Create CMakeLists.txt and copy the below code
• Use CMAKE.exe give path(c://ChartTest) of ChartTest in source and in Bin add bin next to it path(c://ChartTest//Bin) 
•  Click on Configure it will create the Bin folder in that path automatically. Provide ITK and VTK library path if it won't take automatically.
• Then again Click on Configure
• Than Click on Generate
• Now open the Bin folder and click on .sln file
• Click on BuildSolution under Build or press F7 key to Build it in Visual studio 
•  Now draw rectangle using Left click on Chart View you can see the selected cell value on command window.

Code:

QChartwithInteraction.cpp

//VTK

#include "vtkRenderer.h"

#include "vtkRenderWindow.h"

#include <vtkRenderWindowInteractor.h>

#include "vtkSmartPointer.h"

#include <vtkImageData.h>

#include <vtkJPEGReader.h>

//For chart Display 

#include "vtkContextView.h"

#include "vtkContextScene.h"

#include "vtkChartXY.h"

#include "vtkPlot.h"

#include "vtkTable.h"

#include <vtkImageAccumulate.h>

#include<vtkIntArray.h>

#include<vtkImageExtractComponents.h>

#include <vtkCommand.h>

#include <vtkIdTypeArray.h>

#include <vtkSelection.h> // for selecting XY chart 

#include <vtkContextMouseEvent.h>// For Mouse click translation

#include <vtkExtractSelection.h>

#include <vtkChartLegend.h>

#include <vtkAxis.h>

//Qt

#include <QApplication>

#include <QWidget>

#include <QMainWindow>

#include <QHBoxLayout>

#include "QVTKWidget.h"

#include "vtkQtTableView.h"

//------------------------

#define VTK_CREATE(type, name) \

vtkSmartPointer<type> name = vtkSmartPointer<type>::New()

class ChartCallback: public vtkCommand

{

public:

static ChartCallback *New() 

    { return new ChartCallback; }

void Intialize(double * min,QVTKWidget *qvtkWidget)

{

m_min=min;

m_qvtkWidget=qvtkWidget;

}

     

virtual void Execute(vtkObject *caller, unsigned long eventId, void* )

    { 

vtkSmartPointer<vtkChartXY> View = vtkChartXY::SafeDownCast(caller);

int j =View->GetSelectionMode();

       

vtkSmartPointer<vtkChartLegend> leg=View->GetLegend();

j=View->GetNumberOfItems();

       

  if(eventId==75)

  {

  int max=View->GetPlot(0)->GetSelection()->GetNumberOfTuples();

  std::cout<<"Selected Intensity"<<endl;

for(int i=-1;i<max-1;i++)

{

double data=View->GetPlot(0)->GetSelection()->GetComponent(View->GetNumberOfPlots(),i);

data=double(m_min[0]+data);

std::cout<<data<<endl;

}

  }

  View->Update();

  m_qvtkWidget->update();

}

public:

vtkSmartPointer<vtkExtractSelection> m_extract;

vtkSmartPointer<vtkAnnotationLink> m_link;

vtkSmartPointer<vtkSelection> m_sel;

vtkSmartPointer<vtkTable> m_table;

vtkSmartPointer<vtkAnnotationLink> link;

double *m_min;

QVTKWidget *m_qvtkWidget;

};

//---------------------------------------------------------------

int main( int argc, char * argv [] )

{

// Qt initialization

QApplication app(argc, argv);

QMainWindow mainWindow;

mainWindow.setGeometry(0, 0, 1150, 600);

// QVTK set up and initialization

QVTKWidget *qvtkWidget = new QVTKWidget(&mainWindow);

    

//Setting Data Path to VTK Reader 

vtkSmartPointer<vtkJPEGReader> reader=vtkSmartPointer<vtkJPEGReader>::New();

reader->SetFileName("D:\\testing_Dataset\\Data.jpg");//DataSet Path

reader->Update();

double X[2];

reader->GetOutput()->GetScalarRange(X);

//Generate Table 

vtkTable * table= vtkTable::New();     

vtkIntArray* arrX = vtkIntArray::New(); 

arrX->SetName("Intensity");

table->AddColumn(arrX); 

vtkIntArray* arrC = vtkIntArray::New();  

arrC->SetName("No of Pixels"); 

table->AddColumn(arrC); 

vtkSmartPointer<vtkImageExtractComponents> extract = 

    vtkSmartPointer<vtkImageExtractComponents>::New();

extract->SetInput( reader->GetOutput());

    extract->SetComponents( 0 );

    extract->Update();

    vtkSmartPointer<vtkImageAccumulate> histogram = 

    vtkSmartPointer<vtkImageAccumulate>::New();

    histogram->SetInputConnection( extract->GetOutputPort() );

histogram->SetComponentExtent( int(X[0]),int(X[1]),0,0,0,0 );

    histogram->SetComponentOrigin( 0,0,0 );

    histogram->SetComponentSpacing( 1,0,0 );

    histogram->SetIgnoreZero( 0 );

    histogram->Update();

int x = int(X[0]);

int y = int(X[1]);

int range = y-x;

    int* output = static_cast<int*>(histogram->GetOutput()->GetScalarPointer());

table->SetNumberOfRows(range+1);

for( int i = 0; i<=range+1; i++,x++)

      {

 table->SetValue(i,0,x);

 table->SetValue(i,1,*output);

 

 output++;

      }

vtkPlot *line = 0;

//Chart Implimentation

vtkChartXY *chart = vtkChartXY::New();

vtkContextView *view=vtkContextView::New();

line = chart->AddPlot(vtkChart::BAR);

line->SetInput(table,0,1);

chart->GetAxis(vtkAxis::LEFT)->SetTitle("No of Pixel");

chart->GetAxis(vtkAxis::BOTTOM)->SetTitle("intensity");

chart->GetAxis(vtkAxis::BOTTOM)->SetGridVisible(false);

chart->GetAxis(vtkAxis::LEFT)->SetGridVisible(false);

chart->SetForceAxesToBounds(true);//start from minimum range

chart->SetBarWidthFraction(1);

    //Draw Chart

chart->Update();

view->GetScene()->AddItem(chart);

// Translate the Widget Action //Left mouse click for select the chart // Right click for Zoom 

chart->SetActionToButton(vtkChart::SELECT, 

vtkContextMouseEvent::LEFT_BUTTON); 

chart->SetActionToButton(vtkChart::ZOOM, 

vtkContextMouseEvent::RIGHT_BUTTON); 

    //Providing Chart callback

vtkSmartPointer<ChartCallback> cbk =

vtkSmartPointer<ChartCallback>::New();

cbk->Intialize(X,qvtkWidget);

//Important:: This is for telling Callback to send signal if Chart cell will select

chart->AddObserver(vtkSelection::CELL,cbk);

  

//----------------------------------------------------------  

#if VTK_MAJOR_VERSION <= 5

  line->SetInput(table, 0, 1);

  

#else

  line->SetInputData(table, 0, 1);

#endif

line->SetColor(0, 0.5, 255, 255);

//Setting ContexView in QvtkWidget

view->SetInteractor(qvtkWidget->GetInteractor());

qvtkWidget->SetRenderWindow(view->GetRenderWindow());

view->GetRenderWindow()->SetMultiSamples(0);

view->GetInteractor()->Initialize();

// Now lets try to add a table view

QWidget *widget = new QWidget(&mainWindow);

QHBoxLayout *layout = new QHBoxLayout(widget);

VTK_CREATE(vtkQtTableView, tableView);

tableView->SetSplitMultiComponentColumns(true);

tableView->AddRepresentationFromInput(table);

tableView->Update();

layout->addWidget(qvtkWidget, 2);

layout->addWidget(tableView->GetWidget());

mainWindow.setCentralWidget(widget);

// Now show the application and start the event loop

mainWindow.show();

return app.exec();

}

CMakeLists.txt

PROJECT (Charts)

IF(NOT VTK_BINARY_DIR)

FIND_PACKAGE(VTK REQUIRED)

IF(NOT VTK_USE_CHARTS)

  MESSAGE(FATAL_ERROR "Example ${PROJECT_NAME} requires VTK_USE_CHARTS.")

ENDIF(NOT VTK_USE_CHARTS)

INCLUDE(${VTK_USE_FILE})

ENDIF(NOT VTK_BINARY_DIR)

IF(VTK_USE_QVTK)

  FIND_PACKAGE(Qt4 REQUIRED)

  INCLUDE(${QT_USE_FILE})

  INCLUDE_DIRECTORIES(${QT_INCLUDE_DIR})

  ADD_EXECUTABLE(QChartTable QChartwithInteraction.cpp)

  TARGET_LINK_LIBRARIES(QChartTable

    QVTK

    ${QT_LIBRARIES}

    vtkRendering

    vtkCharts

  )

ENDIF(VTK_USE_QVTK)

                             *NOTE: Let me know if you need any modification in it.