ImageStencil
VTKExamples/Cxx/Images/ImageStencil
Description
This example creates a red image and a green image. It creates a mask that is half on and half off. It then combines the images according to the mask using an ImageStencil.
:''See also: [and [../Transparency]''
Code
ImageStencil.cxx
#include <vtkVersion.h>
#include <vtkImageData.h>
#include <vtkImageMapper3D.h>
#include <vtkImageStencil.h>
#include <vtkImageStencilData.h>
#include <vtkImageToImageStencil.h>
#include <vtkJPEGReader.h>
#include <vtkPointData.h>
#include <vtkSmartPointer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkInteractorStyleImage.h>
#include <vtkRenderer.h>
#include <vtkImageActor.h>
static void CreateColorImage(vtkImageData*, unsigned int channel);
static void CreateMask(vtkImageData*);
int main(int, char *[])
{
vtkSmartPointer<vtkImageData> image1 = vtkSmartPointer<vtkImageData>::New();
CreateColorImage(image1, 0); // Create a red image
vtkSmartPointer<vtkImageData> image2 = vtkSmartPointer<vtkImageData>::New();
CreateColorImage(image2, 1); // Create a green image
vtkSmartPointer<vtkImageData> mask = vtkSmartPointer<vtkImageData>::New();
CreateMask(mask);
//vtkSmartPointer<vtkImageStencilData> stencilData = vtkSmartPointer<vtkImageStencilData>::New();
vtkSmartPointer<vtkImageToImageStencil> imageToImageStencil = vtkSmartPointer<vtkImageToImageStencil>::New();
#if VTK_MAJOR_VERSION <= 5
imageToImageStencil->SetInputConnection(mask->GetProducerPort());
#else
imageToImageStencil->SetInputData(mask);
#endif
imageToImageStencil->ThresholdByUpper(122);
vtkSmartPointer<vtkImageStencil> stencil = vtkSmartPointer<vtkImageStencil>::New();
stencil->SetInputConnection(2, imageToImageStencil->GetOutputPort());
stencil->ReverseStencilOn();
#if VTK_MAJOR_VERSION <= 5
stencil->SetBackgroundInput(image2);
stencil->SetInputConnection(image1->GetProducerPort());
#else
stencil->SetBackgroundInputData(image2);
stencil->SetInputData(image1);
#endif
stencil->Update();
// Create an actor
vtkSmartPointer<vtkImageActor> actor = vtkSmartPointer<vtkImageActor>::New();
actor->GetMapper()->SetInputConnection(stencil->GetOutputPort());
// Setup renderer
vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
renderer->AddActor(actor);
renderer->ResetCamera();
// Setup render window
vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->AddRenderer(renderer);
// Setup render window interactor
vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
vtkSmartPointer<vtkInteractorStyleImage> style =
vtkSmartPointer<vtkInteractorStyleImage>::New();
renderWindowInteractor->SetInteractorStyle(style);
// Render and start interaction
renderWindowInteractor->SetRenderWindow(renderWindow);
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
void CreateColorImage(vtkImageData* image, const unsigned int channel)
{
unsigned int dim = 20;
image->SetDimensions(dim, dim, 1);
#if VTK_MAJOR_VERSION <= 5
image->SetNumberOfScalarComponents(3);
image->SetScalarTypeToUnsignedChar();
image->AllocateScalars();
#else
image->AllocateScalars(VTK_UNSIGNED_CHAR,3);
#endif
for(unsigned int x = 0; x < dim; x++)
{
for(unsigned int y = 0; y < dim; y++)
{
unsigned char* pixel = static_cast<unsigned char*>(image->GetScalarPointer(x,y,0));
pixel[0] = 0;
pixel[1] = 0;
pixel[2] = 0;
pixel[channel] = 255;
}
}
image->Modified();
}
static void CreateMask(vtkImageData* image)
{
unsigned int dim = 20;
image->SetDimensions(dim, dim, 1);
#if VTK_MAJOR_VERSION <= 5
image->SetNumberOfScalarComponents(1);
image->SetScalarTypeToUnsignedChar();
image->AllocateScalars();
#else
image->AllocateScalars(VTK_UNSIGNED_CHAR, 1);
#endif
for(unsigned int x = 0; x < dim; x++)
{
for(unsigned int y = 0; y < dim; y++)
{
unsigned char* pixel = static_cast<unsigned char*>(image->GetScalarPointer(x,y,0));
if(x < dim/2)
{
pixel[0] = 0;
}
else
{
pixel[0] = 255;
}
}
}
image->Modified();
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(ImageStencil)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(ImageStencil MACOSX_BUNDLE ImageStencil.cxx)
target_link_libraries(ImageStencil ${VTK_LIBRARIES})
Download and Build ImageStencil
Click here to download ImageStencil and its CMakeLists.txt file. Once the tarball ImageStencil.tar has been downloaded and extracted,
cd ImageStencil/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:
./ImageStencil
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.