ViewportBorders

VTKEx/Cxx/Utilities/ViewportBorders

Description

Sometimes multiple vtkRenderer viewports can be difficult to differentiate. This example draws a border around each viewport. The example creates a vtkPolyLine that outlines the viewport. The coordinates for the vtkPoints are specified in normalized viewport coordinates. The coordinate selection is made with a vtkCoordinate. The vtkPolyDataMapper2D and vtkActor2D render the border.

To run the example, provide 1-N vtkPolyDataReader files.

This examples uses the data v.vtk, t.vtk and k.vtk.

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

ViewportBorders.cxx

#include <vtkSmartPointer.h>

#include <vtkActor.h>
#include <vtkActor2D.h>
#include <vtkCellArray.h>
#include <vtkCoordinate.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkPolyDataMapper2D.h>
#include <vtkPolyDataReader.h>
#include <vtkPolyLine.h>
#include <vtkProperty.h>
#include <vtkProperty2D.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkNamedColors.h>

namespace
{
void ViewportBorder(vtkSmartPointer<vtkRenderer> &renderer,
                    double *color,
                    bool last = false);
}

int main (int argc, char *argv[])
{
  //
  int numberOfFiles = argc - 1;
  if (numberOfFiles == 0)
  {
    std::cout << "Usage" << argv[0]
              << " file1 file2 file3 ... fileN" << std::endl;
    return EXIT_FAILURE;
  }
  vtkSmartPointer<vtkNamedColors> colors =
    vtkSmartPointer<vtkNamedColors>::New();

  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->SetSize(300 * numberOfFiles, 300);

  double size = 1.0 / numberOfFiles;
  for (unsigned int i = 0; static_cast<int>(i) < numberOfFiles; ++i)
  {
    vtkSmartPointer<vtkPolyDataReader> reader =
      vtkSmartPointer<vtkPolyDataReader>::New();
    reader->SetFileName(argv[i + 1]);

    vtkSmartPointer<vtkPolyDataMapper> mapper =
      vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper->SetInputConnection(reader->GetOutputPort());

    vtkSmartPointer<vtkActor> actor =
      vtkSmartPointer<vtkActor>::New();
    actor->SetMapper(mapper);
    actor->GetProperty()->SetColor(colors->GetColor3d("Silver").GetData());

    vtkSmartPointer<vtkRenderer> renderer =
      vtkSmartPointer<vtkRenderer>::New();
    renderer->AddActor(actor);
    renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());

    double viewport[4];
    viewport[0] = size * i;
    viewport[1] = 0.0;
    viewport[2] = size * (i + 1);
    viewport[3] = 1.0;
    renderer->SetViewport(viewport);
    ViewportBorder(renderer,
                   colors->GetColor3d("Gold").GetData(),
                   static_cast<int>(i) == numberOfFiles - 1);
    renderWindow->AddRenderer(renderer);
  }

  vtkSmartPointer<vtkRenderWindowInteractor> interactor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  interactor->SetRenderWindow(renderWindow);
  renderWindow->Render();
  interactor->Initialize();
  interactor->Start();

  return EXIT_SUCCESS;
}
namespace
{
// draw the borders of a renderer's viewport
void ViewportBorder(vtkSmartPointer<vtkRenderer> &renderer,
                    double *color,
                    bool last)
{
  // points start at upper right and proceed anti-clockwise
  vtkSmartPointer<vtkPoints> points =
    vtkSmartPointer<vtkPoints>::New();
  points->SetNumberOfPoints(4);
  points->InsertPoint(0, 1, 1, 0);
  points->InsertPoint(1, 0, 1, 0);
  points->InsertPoint(2, 0, 0, 0);
  points->InsertPoint(3, 1, 0, 0);

  // create cells, and lines
  vtkSmartPointer<vtkCellArray> cells =
    vtkSmartPointer<vtkCellArray>::New();
  cells->Initialize();

  vtkSmartPointer<vtkPolyLine> lines =
    vtkSmartPointer<vtkPolyLine>::New();

  // only draw last line if this is the last viewport
  // this prevents double vertical lines at right border
  // if different colors are used for each border, then do
  // not specify last
  if (last)
  {
    lines->GetPointIds()->SetNumberOfIds(5);
  }
  else
  {
  lines->GetPointIds()->SetNumberOfIds(4);
  }
  for(unsigned int i = 0; i < 4; ++i)
  {
    lines->GetPointIds()->SetId(i,i);
  }
  if (last)
  {
    lines->GetPointIds()->SetId(4, 0);
  }
  cells->InsertNextCell(lines);

  // now make tge polydata and display it
  vtkSmartPointer<vtkPolyData> poly =
    vtkSmartPointer<vtkPolyData>::New();
  poly->Initialize();
  poly->SetPoints(points);
  poly->SetLines(cells);

  // use normalized viewport coordinates since
  // they are independent of window size
  vtkSmartPointer<vtkCoordinate> coordinate =
    vtkSmartPointer<vtkCoordinate>::New();
  coordinate->SetCoordinateSystemToNormalizedViewport();

  vtkSmartPointer<vtkPolyDataMapper2D> mapper =
    vtkSmartPointer<vtkPolyDataMapper2D>::New();
  mapper->SetInputData(poly);
  mapper->SetTransformCoordinate(coordinate);

  vtkSmartPointer<vtkActor2D> actor =
    vtkSmartPointer<vtkActor2D>::New();
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(color);
  // line width should be at least 2 to be visible at extremes

  actor->GetProperty()->SetLineWidth(4.0); // Line Width

  renderer->AddViewProp(actor);
}
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(ViewportBorders)

find_package(VTK COMPONENTS 
  vtkvtkCommonColor
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkIOLegacy
  vtkvtkInteractionStyle
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping ViewportBorders: ${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(ViewportBorders MACOSX_BUNDLE ViewportBorders.cxx )
  target_link_libraries(ViewportBorders PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(ViewportBorders MACOSX_BUNDLE ViewportBorders.cxx )
  target_link_libraries(ViewportBorders PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS ViewportBorders
    MODULES ${VTK_LIBRARIES}
    )
endif ()

Download and Build ViewportBorders

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

cd ViewportBorders/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:

./ViewportBorders

WINDOWS USERS

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