ImageMask
Description¶
This example creates an all red image. Then it creates a mask of a small rectangle. The red pixels in this rectangle are copied to the output image, while the rest of the output image is black. The black region could be set to a different color using SetMaskedOutputValue.
Question
If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum
Code¶
ImageMask.cxx
#include <vtkSmartPointer.h>
#include <vtkImageData.h>
#include <vtkImageMapper3D.h>
#include <vtkJPEGWriter.h>
#include <vtkImageCanvasSource2D.h>
#include <vtkImageMask.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkInteractorStyleImage.h>
#include <vtkRenderer.h>
#include <vtkImageActor.h>
#include <vtkImageEllipsoidSource.h>
#include <vtkImageCast.h>
int main(int, char *[])
{
// Create an image of a rectangle
vtkSmartPointer<vtkImageCanvasSource2D> source =
vtkSmartPointer<vtkImageCanvasSource2D>::New();
source->SetScalarTypeToUnsignedChar();
source->SetNumberOfScalarComponents(3);
source->SetExtent(0, 200, 0, 200, 0, 0);
// Create a red image
source->SetDrawColor(255,0,0);
source->FillBox(0,200,0,200);
source->Update();
// Create a rectanglular mask
vtkSmartPointer<vtkImageCanvasSource2D> maskSource =
vtkSmartPointer<vtkImageCanvasSource2D>::New();
maskSource->SetScalarTypeToUnsignedChar();
maskSource->SetNumberOfScalarComponents(1);
maskSource->SetExtent(0, 200, 0, 200, 0, 0);
// Initialize the mask to black
maskSource->SetDrawColor(0,0,0);
maskSource->FillBox(0,200,0,200);
// Create a square
maskSource->SetDrawColor(255,255,255); //anything non-zero means "make the output pixel equal the input pixel." If the mask is zero, the output pixel is set to MaskedValue
maskSource->FillBox(100,120,100,120);
maskSource->Update();
vtkSmartPointer<vtkImageMask> maskFilter =
vtkSmartPointer<vtkImageMask>::New();
maskFilter->SetInputConnection(0, source->GetOutputPort());
maskFilter->SetInputConnection(1, maskSource->GetOutputPort());
maskFilter->SetMaskedOutputValue(0,1,0);
maskFilter->Update();
vtkSmartPointer<vtkImageMask> inverseMaskFilter =
vtkSmartPointer<vtkImageMask>::New();
inverseMaskFilter->SetInputConnection(0, source->GetOutputPort());
inverseMaskFilter->SetInputConnection(1, maskSource->GetOutputPort());
inverseMaskFilter->SetMaskedOutputValue(0,1,0);
inverseMaskFilter->NotMaskOn();
inverseMaskFilter->Update();
// Create actors
vtkSmartPointer<vtkImageActor> originalActor =
vtkSmartPointer<vtkImageActor>::New();
originalActor->GetMapper()->SetInputConnection(source->GetOutputPort());
vtkSmartPointer<vtkImageActor> maskActor =
vtkSmartPointer<vtkImageActor>::New();
maskActor->GetMapper()->SetInputConnection(maskSource->GetOutputPort());
vtkSmartPointer<vtkImageActor> maskedActor =
vtkSmartPointer<vtkImageActor>::New();
maskedActor->GetMapper()->SetInputConnection(maskFilter->GetOutputPort());
vtkSmartPointer<vtkImageActor> inverseMaskedActor =
vtkSmartPointer<vtkImageActor>::New();
inverseMaskedActor->GetMapper()->SetInputConnection(inverseMaskFilter->GetOutputPort());
// Define viewport ranges
// (xmin, ymin, xmax, ymax)
double originalViewport[4] = {0.0, 0.0, 0.25, 1.0};
double maskViewport[4] = {0.25, 0.0, 0.5, 1.0};
double maskedViewport[4] = {0.5, 0.0, 0.75, 1.0};
double inverseMaskedViewport[4] = {0.75, 0.0, 1.0, 1.0};
// Setup renderers
vtkSmartPointer<vtkRenderer> originalRenderer =
vtkSmartPointer<vtkRenderer>::New();
originalRenderer->SetViewport(originalViewport);
originalRenderer->AddActor(originalActor);
originalRenderer->ResetCamera();
originalRenderer->SetBackground(.4, .5, .6);
vtkSmartPointer<vtkRenderer> maskRenderer =
vtkSmartPointer<vtkRenderer>::New();
maskRenderer->SetViewport(maskViewport);
maskRenderer->AddActor(maskActor);
maskRenderer->ResetCamera();
maskRenderer->SetBackground(.4, .5, .6);
vtkSmartPointer<vtkRenderer> maskedRenderer =
vtkSmartPointer<vtkRenderer>::New();
maskedRenderer->SetViewport(maskedViewport);
maskedRenderer->AddActor(maskedActor);
maskedRenderer->ResetCamera();
maskedRenderer->SetBackground(.4, .5, .6);
vtkSmartPointer<vtkRenderer> inverseMaskedRenderer =
vtkSmartPointer<vtkRenderer>::New();
inverseMaskedRenderer->SetViewport(inverseMaskedViewport);
inverseMaskedRenderer->AddActor(inverseMaskedActor);
inverseMaskedRenderer->ResetCamera();
inverseMaskedRenderer->SetBackground(.4, .5, .7);
vtkSmartPointer<vtkRenderWindow> renderWindow =
vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->SetSize(1000, 250);
renderWindow->AddRenderer(originalRenderer);
renderWindow->AddRenderer(maskRenderer);
renderWindow->AddRenderer(maskedRenderer);
renderWindow->AddRenderer(inverseMaskedRenderer);
vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
vtkSmartPointer<vtkInteractorStyleImage> style =
vtkSmartPointer<vtkInteractorStyleImage>::New();
renderWindowInteractor->SetInteractorStyle(style);
renderWindowInteractor->SetRenderWindow(renderWindow);
renderWindow->Render();
renderWindowInteractor->Initialize();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.3 FATAL_ERROR)
project(ImageMask)
find_package(VTK COMPONENTS
vtkvtkCommonCore
vtkvtkCommonDataModel
vtkvtkIOImage
vtkvtkImagingCore
vtkvtkImagingSources
vtkvtkInteractionStyle
vtkvtkRenderingContextOpenGL2
vtkvtkRenderingCore
vtkvtkRenderingFreeType
vtkvtkRenderingGL2PSOpenGL2
vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
message("Skipping ImageMask: ${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(ImageMask MACOSX_BUNDLE ImageMask.cxx )
target_link_libraries(ImageMask PRIVATE ${VTK_LIBRARIES})
else ()
# include all components
add_executable(ImageMask MACOSX_BUNDLE ImageMask.cxx )
target_link_libraries(ImageMask PRIVATE ${VTK_LIBRARIES})
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS ImageMask
MODULES ${VTK_LIBRARIES}
)
endif ()
Download and Build ImageMask¶
Click here to download ImageMask and its CMakeLists.txt file. Once the tarball ImageMask.tar has been downloaded and extracted,
cd ImageMask/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:
./ImageMask
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.