Re #178: Add option to switch between end-capping methods

By setting the "End capping" parameter, the method used to generate end caps can be changed:
- 0 = leave contours open on surface exterior.
- 1 (default) = close surface by generating smooth end caps.
- 2 = close surface by generating straight end caps.

DicomRtImportExport/ConversionRules/vtkPlanarContourToClosedSurfaceConversionRule.cxx

@@ -83,7 +83,11 @@ vtkPlanarContourToClosedSurfaceConversionRule::vtkPlanarContourToClosedSurfaceCo
   this->ConversionParameters[this->GetDefaultSliceThicknessParameterName()] = std::make_pair("0.0",
     "Default thickness for contours if slice spacing cannot be calculated.");
   this->ConversionParameters[this->GetEndCappingParameterName()] = std::make_pair("1",
-    "Create end cap to close surface inside contours on the top and bottom of the structure. 1 (default) = close surface by generating end caps. 0 = leave contours open on surface exterior.");
+    "Create end cap to close surface inside contours on the top and bottom of the structure.\n"
+    "0 = leave contours open on surface exterior.\n"
+    "1 (default) = close surface by generating smooth end caps.\n"
+    "2 = close surface by generating straight end caps."
+  );
 }
 
 //----------------------------------------------------------------------------
@@ -313,7 +317,7 @@ bool vtkPlanarContourToClosedSurfaceConversionRule::Convert(vtkDataObject* sourc
   }
 
   // Triangulate all contours which are exposed.
-  if (vtkVariant(this->GetConversionParameter(this->GetEndCappingParameterName())).ToInt() == true)
+  if (vtkVariant(this->GetConversionParameter(this->GetEndCappingParameterName())).ToInt() != EndCappingModes::None)
   {
     this->EndCapping(inputContoursCopy, outputPolygons, lineTriganulatedToAbove, lineTriganulatedToBelow);
   }
@@ -1280,6 +1284,68 @@ void vtkPlanarContourToClosedSurfaceConversionRule::CreateEndCapContour(vtkPolyD
     vtkErrorMacro("CreateEndCapContour: invalid vtkCellArray");
   }
 
+  if (vtkVariant(this->GetConversionParameter(this->GetEndCappingParameterName())).ToInt() == EndCappingModes::Smooth)
+  {
+    this->CreateSmoothEndCapContour(inputROIPoints, inputLine, outputLines, lineSpacing);
+  }
+  else if (vtkVariant(this->GetConversionParameter(this->GetEndCappingParameterName())).ToInt() == EndCappingModes::Straight)
+  {
+    this->CreateStraightEndCapContour(inputROIPoints, inputLine, outputLines, lineSpacing);
+  }
+}
+
+//----------------------------------------------------------------------------
+void vtkPlanarContourToClosedSurfaceConversionRule::CreateStraightEndCapContour(vtkPolyData* inputROIPoints, vtkLine* inputLine, vtkCellArray* outputLines, double lineSpacing)
+{
+  if (!inputROIPoints)
+  {
+    vtkErrorMacro("CreateEndCapContour: invalid vtkPolyData");
+    return;
+  }
+
+  if (!inputLine)
+  {
+    vtkErrorMacro("CreateEndCapContour: invalid vtkLine");
+    return;
+  }
+
+  if (!outputLines)
+  {
+    vtkErrorMacro("CreateEndCapContour: invalid vtkCellArray");
+  }
+
+  vtkSmartPointer<vtkPoints> inputPoints = inputROIPoints->GetPoints();
+  vtkNew<vtkIdList> endCapLine;
+  for (int i = 0; i < inputLine->GetNumberOfPoints(); ++i)
+  {
+    double endCapPoint[3] = { 0.0, 0.0, 0.0 };
+    inputPoints->GetPoint(inputLine->GetPointId(i), endCapPoint);
+    endCapPoint[2] += lineSpacing / 2.0;
+    endCapLine->InsertNextId(inputPoints->InsertNextPoint(endCapPoint));
+  }
+  outputLines->InsertNextCell(endCapLine);
+}
+
+//----------------------------------------------------------------------------
+void vtkPlanarContourToClosedSurfaceConversionRule::CreateSmoothEndCapContour(vtkPolyData* inputROIPoints, vtkLine* inputLine, vtkCellArray* outputLines, double lineSpacing)
+{
+  if (!inputROIPoints)
+  {
+    vtkErrorMacro("CreateEndCapContour: invalid vtkPolyData");
+    return;
+  }
+
+  if (!inputLine)
+  {
+    vtkErrorMacro("CreateEndCapContour: invalid vtkLine");
+    return;
+  }
+
+  if (!outputLines)
+  {
+    vtkErrorMacro("CreateEndCapContour: invalid vtkCellArray");
+  }
+
   vtkSmartPointer<vtkCellArray> lines = vtkSmartPointer<vtkCellArray>::New();
   lines->Initialize();
   lines->InsertNextCell(inputLine);

DicomRtImportExport/ConversionRules/vtkPlanarContourToClosedSurfaceConversionRule.h

@@ -58,6 +58,12 @@ class VTK_SLICER_DICOMRTIMPORTEXPORT_CONVERSIONRULES_EXPORT vtkPlanarContourToCl
 
   static const std::string GetDefaultSliceThicknessParameterName() { return "Default slice thickness"; };
   static const std::string GetEndCappingParameterName() { return "End capping"; };
+  enum EndCappingModes
+  {
+    None = 0,
+    Smooth = 1,
+    Straight = 2
+  };
 
   /// Constructs representation object from representation name for the supported representation classes
   /// (typically source and target representation VTK classes, subclasses of vtkDataObject)
@@ -189,6 +195,22 @@ class VTK_SLICER_DICOMRTIMPORTEXPORT_CONVERSIONRULES_EXPORT vtkPlanarContourToCl
   /// \param The size of the spacing between the contours. Contours created by this function will be offset by 1/2 of this amount
   void CreateEndCapContour(vtkPolyData* inputROIPoints, vtkLine* inputLine, vtkCellArray* outputLines, double lineSpacing);
 
+  /// Create smoothly interpolated end cap contours on the exterior of the surface.
+  /// Called by CreateEndCapContour based on the "End capping" conversion parameter.
+  /// \param inputROIPoints Polydata containing all of the points and contours
+  /// \param inputLine The original line that needs to be extended
+  /// \param outputLines Cell array containing all of the lines that are created by the algorithm
+  /// \param The size of the spacing between the contours. Contours created by this function will be offset by 1/2 of this amount
+  void CreateSmoothEndCapContour(vtkPolyData* inputROIPoints, vtkLine* inputLine, vtkCellArray* outputLines, double lineSpacing);
+
+  /// Create straight extruded end cap contours on the exterior of the surface.
+  /// Called by CreateEndCapContour based on the "End capping" conversion parameter.
+  /// \param inputROIPoints Polydata containing all of the points and contours
+  /// \param inputLine The original line that needs to be extended
+  /// \param outputLines Cell array containing all of the lines that are created by the algorithm
+  /// \param The size of the spacing between the contours. Contours created by this function will be offset by 1/2 of this amount
+  void CreateStraightEndCapContour(vtkPolyData* inputROIPoints, vtkLine* inputLine, vtkCellArray* outputLines, double lineSpacing);
+
   /// Triangulate the interior of a contour on the xy plane.
   /// \param Contour that is being triangulated
   /// \param Cell array that the polygons are added to