# ScatterPlot

VTKExamples/Cxx/Plotting/ScatterPlot

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See (Python)

### Code

ScatterPlot.cxx

    #include <vtkSmartPointer.h>

    #include <vtkChartXY.h>
    #include <vtkContextScene.h>
    #include <vtkContextView.h>
    #include <vtkFloatArray.h>
    #include <vtkPlotPoints.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkTable.h>

    int main(int, char*[])
    {
      // Set up a 2D scene, add an XY chart to it
      vtkSmartPointer<vtkContextView> view =
        vtkSmartPointer<vtkContextView>::New();
      view->GetRenderer()->SetBackground(1.0, 1.0, 1.0);
      view->GetRenderWindow()->SetSize(400, 300);

      vtkSmartPointer<vtkChartXY> chart =
        vtkSmartPointer<vtkChartXY>::New();
      view->GetScene()->AddItem(chart);
      chart->SetShowLegend(true);

      // Create a table with some points in it...
      vtkSmartPointer<vtkTable> table =
        vtkSmartPointer<vtkTable>::New();

      vtkSmartPointer<vtkFloatArray> arrX =
        vtkSmartPointer<vtkFloatArray>::New();
      arrX->SetName("X Axis");
      table->AddColumn(arrX);

      vtkSmartPointer<vtkFloatArray> arrC =
        vtkSmartPointer<vtkFloatArray>::New();
      arrC->SetName("Cosine");
      table->AddColumn(arrC);

      vtkSmartPointer<vtkFloatArray> arrS =
        vtkSmartPointer<vtkFloatArray>::New();
      arrS->SetName("Sine");
      table->AddColumn(arrS);

      vtkSmartPointer<vtkFloatArray> arrT =
        vtkSmartPointer<vtkFloatArray>::New();
      arrT->SetName("Sine - Cosine");
      table->AddColumn(arrT);

      // Test charting with a few more points...
      int numPoints = 40;
      float inc = 7.5 / (numPoints-1);
      table->SetNumberOfRows(numPoints);
      for (int i = 0; i < numPoints; ++i)
      {
        table->SetValue(i, 0, i * inc);
        table->SetValue(i, 1, cos(i * inc) + 0.0);
        table->SetValue(i, 2, sin(i * inc) + 0.0);
        table->SetValue(i, 3, sin(i * inc) - cos(i * inc));
      }

      // Add multiple scatter plots, setting the colors etc
      vtkPlot *points = chart->AddPlot(vtkChart::POINTS);
      points->SetInputData(table, 0, 1);
      points->SetColor(0, 0, 0, 255);
      points->SetWidth(1.0);
      vtkPlotPoints::SafeDownCast(points)->SetMarkerStyle(vtkPlotPoints::CROSS);

      points = chart->AddPlot(vtkChart::POINTS);
      points->SetInputData(table, 0, 2);
      points->SetColor(0, 0, 0, 255);
      points->SetWidth(1.0);
      vtkPlotPoints::SafeDownCast(points)->SetMarkerStyle(vtkPlotPoints::PLUS);

      points = chart->AddPlot(vtkChart::POINTS);
      points->SetInputData(table, 0, 3);
      points->SetColor(0, 0, 255, 255);
      points->SetWidth(1.0);
      vtkPlotPoints::SafeDownCast(points)->SetMarkerStyle(vtkPlotPoints::CIRCLE);

      //Finally render the scene
      view->GetRenderWindow()->SetMultiSamples(0);
      view->GetRenderWindow()->Render();
      view->GetInteractor()->Initialize();
      view->GetInteractor()->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ScatterPlot)

    find_package(VTK COMPONENTS
      vtkChartsCore
      vtkCommonCore
      vtkCommonDataModel
      vtkInteractionStyle
      vtkRenderingContext2D
      vtkRenderingContextOpenGL2
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingGL2PSOpenGL2
      vtkRenderingOpenGL2
      vtkViewsContext2D QUIET)
    if (NOT VTK_FOUND)
      message("Skipping ScatterPlot: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(ScatterPlot MACOSX_BUNDLE ScatterPlot.cxx )
      target_link_libraries(ScatterPlot PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(ScatterPlot MACOSX_BUNDLE ScatterPlot.cxx )
      target_link_libraries(ScatterPlot PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS ScatterPlot
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build ScatterPlot

Click here to download ScatterPlot and its CMakeLists.txt file. Once the tarball ScatterPlot.tar has been downloaded and extracted,

    cd ScatterPlot/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./ScatterPlot

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.