Circle

Repository source: Circle

Description¶

A circle is simply the limiting case of a regular polygon. We use vtkRegularPolygonSource with a large number of Sides to approximate a circle.

Other languages

See (Python), (Java)

Question

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

Code¶

Circle.cxx

// Classes specific to this example.
#include <vtkPolyDataMapper.h>
#include <vtkRegularPolygonSource.h>
// Generic VTK pipeline elements.
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
// Auxiliary classes.
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkProperty.h>

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

  // Create a circle
  vtkNew<vtkRegularPolygonSource> polygonSource;
  // Comment this line to generate a disk instead of a circle.
  polygonSource->GeneratePolygonOff();
  polygonSource->SetNumberOfSides(50);
  polygonSource->SetRadius(5);
  polygonSource->SetCenter(0, 0, 0);

  // Visualize
  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(polygonSource->GetOutputPort());

  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(colors->GetColor3d("Cornsilk").GetData());

  vtkNew<vtkRenderer> renderer;
  renderer->AddActor(actor);
  renderer->SetBackground(colors->GetColor3d("DarkGreen").GetData());

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);

  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  renderWindowInteractor->SetRenderWindow(renderWindow);

  renderWindow->SetWindowName("Circle");
  renderWindow->Render();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

CMakeLists.txt¶

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(Circle)

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

if (NOT VTK_FOUND)
  message(FATAL_ERROR "Circle: 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(Circle MACOSX_BUNDLE Circle.cxx )
  target_link_libraries(Circle PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS Circle
  MODULES ${VTK_LIBRARIES}
)

Download and Build Circle¶

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

cd Circle/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:

./Circle

WINDOWS USERS

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