ImageClip
vtk-examples/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 <vtkActor.h>
#include <vtkBorderRepresentation.h>
#include <vtkBorderWidget.h>
#include <vtkCommand.h>
#include <vtkImageActor.h>
#include <vtkImageClip.h>
#include <vtkImageData.h>
#include <vtkImageMapper3D.h>
#include <vtkInformation.h>
#include <vtkInteractorStyleImage.h>
#include <vtkJPEGReader.h>
#include <vtkMath.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkProperty2D.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkStreamingDemandDrivenPipeline.h>
#include <vtkXMLPolyDataReader.h>
#include <string>
namespace {
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
auto lowerLeftCoordinate =
static_cast<vtkBorderRepresentation*>(borderWidget->GetRepresentation())
->GetPositionCoordinate();
auto lowerLeft =
lowerLeftCoordinate->GetComputedWorldValue(this->LeftRenderer);
std::cout << "Lower left coordinate: " << lowerLeft[0] << ", "
<< lowerLeft[1] << ", " << lowerLeft[2] << std::endl;
auto upperRightCoordinate =
static_cast<vtkBorderRepresentation*>(borderWidget->GetRepresentation())
->GetPosition2Coordinate();
auto 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;
};
} // namespace
int main(int argc, char* argv[])
{
vtkNew<vtkNamedColors> color;
// Parse input arguments
if (argc != 2)
{
std::cerr << "Usage: " << argv[0] << " Filename(.jpg) e.g. Gourds2.jpg"
<< std::endl;
return EXIT_FAILURE;
}
std::string inputFilename = argv[1];
// Read the image
vtkNew<vtkJPEGReader> jPEGReader;
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;
vtkNew<vtkImageActor> imageActor;
imageActor->GetMapper()->SetInputConnection(jPEGReader->GetOutputPort());
vtkNew<vtkRenderWindow> renderWindow;
vtkNew<vtkRenderWindowInteractor> interactor;
vtkNew<vtkInteractorStyleImage> style;
interactor->SetInteractorStyle(style);
vtkNew<vtkBorderWidget> borderWidget;
borderWidget->SetInteractor(interactor);
static_cast<vtkBorderRepresentation*>(borderWidget->GetRepresentation())
->GetBorderProperty()
->SetColor(color->GetColor3d("Lime").GetData());
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
vtkNew<vtkRenderer> leftRenderer;
renderWindow->AddRenderer(leftRenderer);
leftRenderer->SetViewport(leftViewport);
leftRenderer->SetBackground(color->GetColor3d("DarkSlateGray").GetData());
vtkNew<vtkRenderer> rightRenderer;
renderWindow->AddRenderer(rightRenderer);
rightRenderer->SetViewport(rightViewport);
rightRenderer->SetBackground(color->GetColor3d("DimGray").GetData());
leftRenderer->AddActor(imageActor);
leftRenderer->ResetCamera();
rightRenderer->ResetCamera();
vtkNew<vtkImageClip> imageClip;
imageClip->SetInputConnection(jPEGReader->GetOutputPort());
jPEGReader->UpdateInformation();
imageClip->SetOutputWholeExtent(jPEGReader->GetOutputInformation(0)->Get(
vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT()));
imageClip->ClipDataOn();
vtkNew<vtkImageActor> clipActor;
clipActor->GetMapper()->SetInputConnection(imageClip->GetOutputPort());
rightRenderer->AddActor(clipActor);
vtkNew<vtkBorderCallback2> borderCallback;
borderCallback->SetLeftRenderer(leftRenderer);
borderCallback->SetImageActor(imageActor);
borderCallback->SetClipFilter(imageClip);
borderWidget->AddObserver(vtkCommand::InteractionEvent, borderCallback);
renderWindow->SetWindowName("ImageClip");
renderWindow->Render();
borderWidget->On();
interactor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(ImageClip)
find_package(VTK COMPONENTS
vtkCommonColor
vtkCommonCore
vtkCommonDataModel
vtkCommonExecutionModel
vtkIOImage
vtkIOXML
vtkImagingCore
vtkInteractionStyle
vtkInteractionWidgets
vtkRenderingContextOpenGL2
vtkRenderingCore
vtkRenderingFreeType
vtkRenderingGL2PSOpenGL2
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()
# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
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.