Screenshot
VTKExamples/Cxx/Utilities/Screenshot
Description¶
This example shows how to save the window to a file (png in this case). You can combine this with the KeypressEvents example to make a useful functionality.
Code¶
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; }
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) target_link_libraries(Screenshot ${VTK_LIBRARIES})
Download and Build Screenshot¶
Danger
The generation of tar files has not been ported to the new VTKExamples. Some tarballs may be missing or out-of-date.
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.