ImageClip
VTKExamples/Cxx/Interaction/ImageClip
Description¶
This example loads an image into the left half of the window. When you move the border widget (the green square in the bottom left corner) over the image, the region that is selected is displayed in the right half of the window.
Question
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Code¶
ImageClip.cxx
#include <vtkSmartPointer.h> #include <vtkActor.h> #include <vtkBorderRepresentation.h> #include <vtkBorderWidget.h> #include <vtkCommand.h> #include <vtkImageActor.h> #include <vtkImageClip.h> #include <vtkImageData.h> #include <vtkImageMapper3D.h> #include <vtkInteractorStyleImage.h> #include <vtkJPEGReader.h> #include <vtkMath.h> #include <vtkProperty2D.h> #include <vtkRenderer.h> #include <vtkRenderWindow.h> #include <vtkRenderWindowInteractor.h> #include <vtkXMLPolyDataReader.h> #include <vtkInformation.h> #include <vtkStreamingDemandDrivenPipeline.h> #include <string> class vtkBorderCallback2 : public vtkCommand { public: vtkBorderCallback2(){} static vtkBorderCallback2 *New() { return new vtkBorderCallback2; } virtual void Execute(vtkObject *caller, unsigned long, void*) { vtkBorderWidget *borderWidget = reinterpret_cast<vtkBorderWidget*>(caller); // Get the world coordinates of the two corners of the box vtkCoordinate* lowerLeftCoordinate = static_cast<vtkBorderRepresentation*> (borderWidget->GetRepresentation())->GetPositionCoordinate(); double* lowerLeft = lowerLeftCoordinate->GetComputedWorldValue(this->LeftRenderer); std::cout << "Lower left coordinate: " << lowerLeft[0] << ", " << lowerLeft[1] << ", " << lowerLeft[2] << std::endl; vtkCoordinate* upperRightCoordinate = static_cast<vtkBorderRepresentation*> (borderWidget->GetRepresentation())->GetPosition2Coordinate(); double* upperRight = upperRightCoordinate ->GetComputedWorldValue(this->LeftRenderer); std::cout << "Upper right coordinate: " << upperRight[0] << ", " << upperRight[1] << ", " << upperRight[2] << std::endl; double* bounds = this->ImageActor->GetBounds(); double xmin = bounds[0]; double xmax = bounds[1]; double ymin = bounds[2]; double ymax = bounds[3]; if( (lowerLeft[0] > xmin) && (upperRight[0] < xmax) && (lowerLeft[1] > ymin) && (upperRight[1] < ymax) ) { this->ClipFilter->SetOutputWholeExtent( vtkMath::Round(lowerLeft[0]), vtkMath::Round(upperRight[0]), vtkMath::Round(lowerLeft[1]), vtkMath::Round(upperRight[1]), 0, 1); } else { std::cout << "box is NOT inside image" << std::endl; } } void SetLeftRenderer(vtkSmartPointer<vtkRenderer> renderer) {this->LeftRenderer = renderer;} void SetImageActor(vtkSmartPointer<vtkImageActor> actor) {this->ImageActor = actor;} void SetClipFilter(vtkSmartPointer<vtkImageClip> clip) {this->ClipFilter = clip;} private: vtkSmartPointer<vtkRenderer> LeftRenderer; vtkSmartPointer<vtkImageActor> ImageActor; vtkSmartPointer<vtkImageClip> ClipFilter; }; int main(int argc, char* argv[]) { // Parse input arguments if ( argc != 2 ) { std::cerr << "Usage: " << argv[0] << " Filename(.jpg)" << std::endl; return EXIT_FAILURE; } std::string inputFilename = argv[1]; // Read the image vtkSmartPointer<vtkJPEGReader> jPEGReader = vtkSmartPointer<vtkJPEGReader>::New(); if( !jPEGReader->CanReadFile( inputFilename.c_str() ) ) { std::cout << "Error: cannot read " << inputFilename << std::endl; return EXIT_FAILURE; } jPEGReader->SetFileName ( inputFilename.c_str() ); jPEGReader->Update(); int extent[6]; jPEGReader->GetOutput()->GetExtent(extent); //xmin, xmax, ymin, ymax //std::cout << "extent: " << extent[0] << " " << extent[1] << " " << //extent[2] << " " << extent[3] << " " << extent[4] << " " << //extent[5] << std::endl; vtkSmartPointer<vtkImageActor> imageActor = vtkSmartPointer<vtkImageActor>::New(); imageActor->GetMapper()->SetInputConnection(jPEGReader->GetOutputPort()); vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New(); vtkSmartPointer<vtkRenderWindowInteractor> interactor = vtkSmartPointer<vtkRenderWindowInteractor>::New(); vtkSmartPointer<vtkInteractorStyleImage> style = vtkSmartPointer<vtkInteractorStyleImage>::New(); interactor->SetInteractorStyle( style ); vtkSmartPointer<vtkBorderWidget> borderWidget = vtkSmartPointer<vtkBorderWidget>::New(); borderWidget->SetInteractor(interactor); static_cast<vtkBorderRepresentation*> (borderWidget->GetRepresentation())->GetBorderProperty()->SetColor(0,1,0); borderWidget->SelectableOff(); interactor->SetRenderWindow(renderWindow); // Define viewport ranges in normalized coordinates // (xmin, ymin, xmax, ymax) double leftViewport[4] = {0.0, 0.0, 0.5, 1.0}; double rightViewport[4] = {0.5, 0.0, 1.0, 1.0}; // Setup both renderers vtkSmartPointer<vtkRenderer> leftRenderer = vtkSmartPointer<vtkRenderer>::New(); leftRenderer->SetBackground(1,0,0); renderWindow->AddRenderer(leftRenderer); leftRenderer->SetViewport(leftViewport); vtkSmartPointer<vtkRenderer> rightRenderer = vtkSmartPointer<vtkRenderer>::New(); renderWindow->AddRenderer(rightRenderer); rightRenderer->SetViewport(rightViewport); leftRenderer->AddActor(imageActor); leftRenderer->ResetCamera(); rightRenderer->ResetCamera(); vtkSmartPointer<vtkImageClip> imageClip = vtkSmartPointer<vtkImageClip>::New(); imageClip->SetInputConnection(jPEGReader->GetOutputPort()); jPEGReader->UpdateInformation(); imageClip->SetOutputWholeExtent( jPEGReader->GetOutputInformation(0)->Get( vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT())); imageClip->ClipDataOn(); vtkSmartPointer<vtkImageActor> clipActor = vtkSmartPointer<vtkImageActor>::New(); clipActor->GetMapper()->SetInputConnection( imageClip->GetOutputPort()); rightRenderer->AddActor(clipActor); vtkSmartPointer<vtkBorderCallback2> borderCallback = vtkSmartPointer<vtkBorderCallback2>::New(); borderCallback->SetLeftRenderer(leftRenderer); borderCallback->SetImageActor(imageActor); borderCallback->SetClipFilter(imageClip); borderWidget->AddObserver(vtkCommand::InteractionEvent,borderCallback); renderWindow->Render(); borderWidget->On(); interactor->Start(); return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR) project(ImageClip) find_package(VTK COMPONENTS vtkCommonCore vtkCommonDataModel vtkCommonExecutionModel vtkIOImage vtkIOXML vtkImagingCore vtkInteractionStyle vtkInteractionWidgets vtkRenderingCore vtkRenderingFreeType vtkRenderingOpenGL2 QUIET) if (NOT VTK_FOUND) message("Skipping ImageClip: ${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(ImageClip MACOSX_BUNDLE ImageClip.cxx ) target_link_libraries(ImageClip PRIVATE ${VTK_LIBRARIES}) else () # include all components add_executable(ImageClip MACOSX_BUNDLE ImageClip.cxx ) target_link_libraries(ImageClip PRIVATE ${VTK_LIBRARIES}) # vtk_module_autoinit is needed vtk_module_autoinit( TARGETS ImageClip MODULES ${VTK_LIBRARIES} ) endif ()
Download and Build ImageClip¶
Click here to download ImageClip and its CMakeLists.txt file. Once the tarball ImageClip.tar has been downloaded and extracted,
cd ImageClip/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:
./ImageClip
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.