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.
Other Languages
See (Python)
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); #if VTK_MAJOR_VERSION > 8 || VTK_MAJOR_VERSION == 8 && VTK_MINOR_VERSION >= 1 windowToImageFilter->SetScale(2); //image quality #else windowToImageFilter->SetMagnification(2); //image quality #endif 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 3.3 FATAL_ERROR) project(Screenshot) find_package(VTK COMPONENTS vtkCommonCore vtkCommonDataModel vtkFiltersSources vtkIOImage vtkInteractionStyle vtkRenderingCore vtkRenderingFreeType vtkRenderingOpenGL2 QUIET) if (NOT VTK_FOUND) message("Skipping Screenshot: ${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(Screenshot MACOSX_BUNDLE Screenshot.cxx ) target_link_libraries(Screenshot PRIVATE ${VTK_LIBRARIES}) else () # include all components add_executable(Screenshot MACOSX_BUNDLE Screenshot.cxx ) target_link_libraries(Screenshot PRIVATE ${VTK_LIBRARIES}) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS Screenshot MODULES ${VTK_LIBRARIES} ) 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
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.