CenterAnImage
VTKExamples/Cxx/Images/CenterAnImage
Description
This moves (0,0) from the bottom left corner of the image to the center of the image.
Code
CenterAnImage.cxx
#include <vtkVersion.h>
#include <vtkSmartPointer.h>
#include <vtkActor.h>
#include <vtkBorderRepresentation.h>
#include <vtkBorderWidget.h>
#include <vtkCommand.h>
#include <vtkImageActor.h>
#include <vtkImageMapper3D.h>
#include <vtkImageChangeInformation.h>
#include <vtkImageClip.h>
#include <vtkImageData.h>
#include <vtkInteractorStyleImage.h>
#include <vtkJPEGReader.h>
#include <vtkMath.h>
#include <vtkProperty2D.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkXMLPolyDataReader.h>
class vtkBorderCallback : public vtkCommand
{
public:
vtkBorderCallback(){}
static vtkBorderCallback *New()
{
return new vtkBorderCallback;
}
virtual void Execute(vtkObject *caller, unsigned long, void*);
void SetRenderer(vtkSmartPointer<vtkRenderer> renderer)
{
this->Renderer = renderer;
}
void SetImageActor(vtkSmartPointer<vtkImageActor> actor)
{
this->ImageActor = actor;
}
private:
vtkSmartPointer<vtkRenderer> Renderer;
vtkSmartPointer<vtkImageActor> ImageActor;
};
int main(int argc, char* argv[])
{
if ( argc != 2 )
{
std::cerr << "Usage: " << argv[0]
<< " Required parameters: Filename" << 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() ) )
{
cout << "Error: cannot read " << inputFilename.c_str() << std::endl;
return EXIT_FAILURE;
}
jPEGReader->SetFileName ( inputFilename.c_str() );
jPEGReader->Update();
// Shift the image center to (0,0)
int dims[3];
jPEGReader->GetOutput()->GetDimensions(dims);
vtkSmartPointer<vtkImageChangeInformation> changeInformation =
vtkSmartPointer<vtkImageChangeInformation>::New();
changeInformation->SetInputConnection(jPEGReader->GetOutputPort());
changeInformation->CenterImageOn();
changeInformation->Update();
vtkSmartPointer<vtkImageData> image =
changeInformation->GetOutput();
vtkSmartPointer<vtkImageActor> imageActor =
vtkSmartPointer<vtkImageActor>::New();
#if VTK_MAJOR_VERSION <= 5
imageActor->SetInput(image);
#else
imageActor->GetMapper()->SetInputData(image);
#endif
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);
// Setup both renderers
vtkSmartPointer<vtkRenderer> renderer =
vtkSmartPointer<vtkRenderer>::New();
renderer->SetBackground(1,0,0);
renderWindow->AddRenderer(renderer);
renderer->AddActor(imageActor);
renderer->ResetCamera();
vtkSmartPointer<vtkBorderCallback> borderCallback =
vtkSmartPointer<vtkBorderCallback>::New();
borderCallback->SetRenderer(renderer);
borderCallback->SetImageActor(imageActor);
borderWidget->AddObserver(vtkCommand::InteractionEvent,borderCallback);
borderWidget->On();
renderWindow->Render();
interactor->Start();
return EXIT_SUCCESS;
}
void vtkBorderCallback::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->Renderer);
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->Renderer);
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) )
{
//std::cout << "box is inside image" << std::endl;
//std::cout << "xmin: " << xmin << " xmax: " << xmax << " ymin: " << ymin << " ymax: " << ymax << std::endl;
}
else
{
std::cout << "box is NOT inside image" << std::endl;
}
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(CenterAnImage)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(CenterAnImage MACOSX_BUNDLE CenterAnImage.cxx)
target_link_libraries(CenterAnImage ${VTK_LIBRARIES})
Download and Build CenterAnImage
Click here to download CenterAnImage and its CMakeLists.txt file. Once the tarball CenterAnImage.tar has been downloaded and extracted,
cd CenterAnImage/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:
./CenterAnImage
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.