AreaPlot

VTKEx/Cxx/Plotting/AreaPlot

Description

This example illustrates vtkPlotArea, which draws a filled region between two curves. The example uses a valid mask to select the values to define the region to be plotted.

The example also shows how to control the size and colors of the plot's components.

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

Code

AreaPlot.cxx

#include <vtkNew.h>
#include <vtkPlotArea.h>

#include <vtkNamedColors.h>

#include <vtkChartXY.h>
#include <vtkAxis.h>
#include <vtkBrush.h>
#include <vtkCharArray.h>
#include <vtkContextScene.h>
#include <vtkContextView.h>
#include <vtkFloatArray.h>
#include <vtkPlot.h>
#include <vtkTextProperty.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkTable.h>

#include <algorithm>
//----------------------------------------------------------------------------
int main( int, char * [] )
{
  vtkNew<vtkNamedColors> colors;

  // Set up a 2D scene, add an XY chart to it
  vtkNew<vtkContextView> view;
  view->GetRenderWindow()->SetSize(640, 480);

  vtkNew<vtkChartXY> chart;
  chart->SetTitle("Area Plot");
  chart->GetTitleProperties()->SetFontSize(36);
  chart->GetTitleProperties()->SetColor(colors->GetColor3d("Banana").GetData());

  chart->GetAxis(0)->GetTitleProperties()->SetFontSize(24);
  chart->GetAxis(0)->GetTitleProperties()->SetColor(colors->GetColor3d("orange").GetData());
  chart->GetAxis(0)->GetLabelProperties()->SetColor(colors->GetColor3d("beige").GetData());
  chart->GetAxis(0)->GetLabelProperties()->SetFontSize(18);

  chart->GetAxis(1)->GetTitleProperties()->SetFontSize(24);
  chart->GetAxis(1)->GetTitleProperties()->SetColor(colors->GetColor3d("orange").GetData());
  chart->GetAxis(1)->GetLabelProperties()->SetColor(colors->GetColor3d("beige").GetData());
  chart->GetAxis(1)->GetLabelProperties()->SetFontSize(18);

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

  // Create a table with some points in it...
  vtkNew<vtkTable> table;

  vtkNew<vtkFloatArray> arrX;
  arrX->SetName("X Axis");
  table->AddColumn(arrX);

  vtkNew<vtkFloatArray> arrC;
  arrC->SetName("Cosine");
  table->AddColumn(arrC);

  vtkNew<vtkFloatArray> arrS;
  arrS->SetName("Sine");
  table->AddColumn(arrS);

  vtkNew<vtkFloatArray> arrS2;
  arrS2->SetName("Sine2");
  table->AddColumn(arrS2);

  vtkNew<vtkFloatArray> arrS3;
  arrS3->SetName("Sine3");
  table->AddColumn(arrS3);

  vtkNew<vtkFloatArray> arr1;
  arr1->SetName("One");
  table->AddColumn(arr1);

  vtkNew<vtkCharArray> validMask;
  validMask->SetName("ValidMask");
  table->AddColumn(validMask);

  // Test charting with a few more points...
  int numPoints = 69;
  float inc = 7.5 / (numPoints-1);
  table->SetNumberOfRows(numPoints);
  for (int i = 0; i < numPoints; ++i)
  {
    table->SetValue(i, 0, i * inc + 0.01);
    table->SetValue(i, 1, cos(i * inc) + 0.01);
    table->SetValue(i, 2, sin(i * inc) + 0.01);
    table->SetValue(i, 3, sin(i * inc) + 0.5);
    table->SetValue(i, 4, sin(i * inc) * sin(i * inc) + 0.01);
    table->SetValue(i, 5, 1.0);

    validMask->SetValue(i, (i > 30 && i < 40) ? 0 : 1);
  }

  // Add multiple line plots, setting the colors etc
  vtkColor3d color3d = colors->GetColor3d("tomato");
  vtkPlotArea* area = dynamic_cast<vtkPlotArea*>(chart->AddPlot(vtkChart::AREA));
  area->SetInputData(table);
  area->SetInputArray(0, "X Axis");
  area->SetInputArray(1, "Sine");
  area->SetInputArray(2, "Sine2");
  area->SetValidPointMaskName("ValidMask");
  area->GetBrush()->SetColorF(color3d.GetRed(),
                              color3d.GetGreen(),
                              color3d.GetBlue(),
                              .6);

  chart->GetAxis(vtkAxis::LEFT)->SetLogScale(true);

  // Render the scene and compare the image to a reference image
  view->GetRenderer()->SetBackground(colors->GetColor3d("SlateGray").GetData());
  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(AreaPlot)

find_package(VTK COMPONENTS 
  vtkvtkChartsCore
  vtkvtkCommonColor
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkInteractionStyle
  vtkvtkRenderingContext2D
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2
  vtkvtkViewsContext2D QUIET)
if (NOT VTK_FOUND)
  message("Skipping AreaPlot: ${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(AreaPlot MACOSX_BUNDLE AreaPlot.cxx )
  target_link_libraries(AreaPlot PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(AreaPlot MACOSX_BUNDLE AreaPlot.cxx )
  target_link_libraries(AreaPlot PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS AreaPlot
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build AreaPlot

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

cd AreaPlot/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:

./AreaPlot

WINDOWS USERS

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