ImageMirrorPad

Description¶

This example shows how to enlarge an image and fill in the padded edges by mirroring the original pixels.

Question

If you have a question about this example, please use the VTK Discourse Forum

Code¶

ImageMirrorPad.cxx

#include <vtkImageActor.h>
#include <vtkImageCanvasSource2D.h>
#include <vtkImageMapper3D.h>
#include <vtkImageMirrorPad.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkType.h>

int main(int, char*[])
{
  vtkNew<vtkNamedColors> colors;

  // Create an image.
  vtkNew<vtkImageCanvasSource2D> source;
  source->SetExtent(0, 20, 0, 20, 0, 0);
  source->SetScalarTypeToUnsignedChar();
  source->SetDrawColor(0.0, 0.0, 0.0, 1.0);
  source->FillBox(-VTK_INT_MAX, VTK_INT_MAX, -VTK_INT_MAX, VTK_INT_MAX);
  source->SetDrawColor(255.0, 0.0, 0.0, 0.5);
  source->DrawCircle(10, 10, 5);
  source->Update();

  vtkNew<vtkImageMirrorPad> mirrorPadFilter;
  mirrorPadFilter->SetInputConnection(source->GetOutputPort());
  mirrorPadFilter->SetOutputWholeExtent(-10, 30, -10, 30, 0, 0);
  mirrorPadFilter->Update();

  // Create an actor.
  vtkNew<vtkImageActor> actor;
  actor->GetMapper()->SetInputConnection(mirrorPadFilter->GetOutputPort());

  // Visualize.
  vtkNew<vtkRenderer> renderer;
  renderer->AddActor(actor);
  renderer->ResetCamera();
  renderer->SetBackground(colors->GetColor3d("Salmon").GetData());

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetWindowName("ImageMirrorPad");

  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;

  renderWindowInteractor->SetRenderWindow(renderWindow);
  renderWindow->Render();
  renderWindowInteractor->Initialize();

  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(ImageMirrorPad)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  ImagingCore
  ImagingSources
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "ImageMirrorPad: Unable to find the VTK build folder.")
endif()

# 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(ImageMirrorPad MACOSX_BUNDLE ImageMirrorPad.cxx )
  target_link_libraries(ImageMirrorPad PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS ImageMirrorPad
  MODULES ${VTK_LIBRARIES}
)

Download and Build ImageMirrorPad¶

Click here to download ImageMirrorPad and its CMakeLists.txt file. Once the tarball ImageMirrorPad.tar has been downloaded and extracted,

cd ImageMirrorPad/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:

./ImageMirrorPad

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.