VTK/Examples/Cxx/Utilities/Screenshot

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Output file

This example shows how to save the window to a file (png in this case). You can combine this with the handle keypress events example to make a useful functionality.

Screenshot.cxx

#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkSmartPointer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkPolyData.h>
#include <vtkSphereSource.h>
#include <vtkWindowToImageFilter.h>
#include <vtkPNGWriter.h>

int main(int, char *[])
{
  vtkSmartPointer<vtkSphereSource> sphereSource = 
    vtkSmartPointer<vtkSphereSource>::New();
  sphereSource->SetCenter(0.0, 0.0, 0.0);
  sphereSource->SetRadius(5.0);
  sphereSource->Update();

  // Visualize
  vtkSmartPointer<vtkPolyDataMapper> mapper = 
    vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(sphereSource->GetOutputPort());

  vtkSmartPointer<vtkActor> actor = 
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);

  vtkSmartPointer<vtkRenderer> renderer = 
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow = 
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  renderWindow->SetAlphaBitPlanes(1); //enable usage of alpha channel

  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = 
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  renderer->AddActor(actor);
  renderer->SetBackground(1,1,1); // Background color white

  renderWindow->Render();

  // Screenshot  
  vtkSmartPointer<vtkWindowToImageFilter> windowToImageFilter = 
    vtkSmartPointer<vtkWindowToImageFilter>::New();
  windowToImageFilter->SetInput(renderWindow);
  windowToImageFilter->SetMagnification(3); //set the resolution of the output image (3 times the current resolution of vtk render window)
  windowToImageFilter->SetInputBufferTypeToRGBA(); //also record the alpha (transparency) channel
  windowToImageFilter->ReadFrontBufferOff(); // read from the back buffer
  windowToImageFilter->Update();
  
  vtkSmartPointer<vtkPNGWriter> writer = 
    vtkSmartPointer<vtkPNGWriter>::New();
  writer->SetFileName("screenshot2.png");
  writer->SetInputConnection(windowToImageFilter->GetOutputPort());
  writer->Write();
  
  renderWindow->Render();  
  renderer->ResetCamera();
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

Please try the new VTKExamples website.

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

PROJECT(Screenshot)

find_package(VTK REQUIRED)
include(${VTK_USE_FILE})

add_executable(Screenshot MACOSX_BUNDLE Screenshot.cxx)

if(VTK_LIBRARIES)
  target_link_libraries(Screenshot ${VTK_LIBRARIES})
else()
  target_link_libraries(Screenshot vtkHybrid vtkWidgets)
endif()

Download and Build Screenshot

Click here to download Screenshot. and its CMakeLists.txt file.

Once the tarball Screenshot.tar has been downloaded and extracted,

cd Screenshot/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:

./Screenshot

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

Comments

Sphere and background color.