PNGWriter

VTKEx/Cxx/IO/PNGWriter

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

PNGWriter.cxx

#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;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(PNGWriter)

find_package(VTK COMPONENTS 
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkIOImage
  vtkvtkImagingCore
  vtkvtkImagingSources 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 ()

Download and Build PNGWriter

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

cd PNGWriter/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:

./PNGWriter

WINDOWS USERS

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