PNGWriter

#include <vtkImageData.h>
#include <vtkPNGWriter.h>
#include <vtkSmartPointer.h>
#include <vtkImageCanvasSource2D.h>
#include <vtkImageCast.h>

int main(int argc, char *argv[])
{
  std::string outputFilename;
  if( argc > 1)
  {
    outputFilename = argv[1];
  }
  else
  {
    outputFilename = "output.png";
  }

  int extent[6] = {0, 99, 0, 99, 0, 0};
  vtkSmartPointer<vtkImageCanvasSource2D> imageSource =
    vtkSmartPointer<vtkImageCanvasSource2D>::New();
  imageSource->SetExtent(extent);
  imageSource->SetScalarTypeToUnsignedChar();
  imageSource->SetNumberOfScalarComponents(3);
  imageSource->SetDrawColor(127, 45, 255);
  imageSource->FillBox(0, 99, 0, 99);
  imageSource->SetDrawColor(255,255,255);
  imageSource->FillBox(40, 70, 20, 50);
  imageSource->Update();

  vtkSmartPointer<vtkImageCast> castFilter =
    vtkSmartPointer<vtkImageCast>::New();
  castFilter->SetOutputScalarTypeToUnsignedChar ();
  castFilter->SetInputConnection(imageSource->GetOutputPort());
  castFilter->Update();

  vtkSmartPointer<vtkPNGWriter> writer =
    vtkSmartPointer<vtkPNGWriter>::New();
  writer->SetFileName(outputFilename.c_str());
  writer->SetInputConnection(castFilter->GetOutputPort());
  writer->Write();

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(PNGWriter)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkCommonDataModel
  vtkIOImage
  vtkImagingCore
  vtkImagingSources QUIET)
if (NOT VTK_FOUND)
  message("Skipping PNGWriter: ${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(PNGWriter MACOSX_BUNDLE PNGWriter.cxx )
  target_link_libraries(PNGWriter PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(PNGWriter MACOSX_BUNDLE PNGWriter.cxx )
  target_link_libraries(PNGWriter PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS PNGWriter
    MODULES ${VTK_LIBRARIES}
    )
endif () 

cd PNGWriter/build 

cmake ..

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

make

./PNGWriter