Added convenience methods to vtkContourFilter.

Added two sets of convenience methods:
1. Set/GetContourValues() with vector<double> (instead of
individually setting the contour values.
2. SetInputArray() which enables setting the name of the
array to process without using the cumbersome SetInputArrayToProcess()

Filters/Core/Testing/Cxx/TestContourImplicitArrays.cxx

@@ -54,7 +54,7 @@ int TestContourImplicitArrays(int argc, char* argv[])
 
   vtkNew<vtkContourFilter> contour;
   contour->SetInputData(baseGrid);
-  contour->SetValue(0, 0.0);
+  contour->SetContourValues({ 0.0 });
 
   contour->Update();
 

Filters/Core/Testing/Cxx/TestResampleWithDataSet2.cxx

@@ -59,9 +59,8 @@ int TestResampleWithDataSet2(int argc, char* argv[])
   // Render
   vtkNew<vtkContourFilter> toPoly;
   toPoly->SetInputData(result);
-  toPoly->SetInputArrayToProcess(
-    0, 0, 0, vtkDataObject::FIELD_ASSOCIATION_POINTS, "vtkValidPointMask");
-  toPoly->SetValue(0, 0.5);
+  toPoly->SetInputArray("vtkValidPointMask");
+  toPoly->SetContourValues({ 0.5 });
 
   vtkNew<vtkArrayCalculator> calculator;
   calculator->SetInputConnection(toPoly->GetOutputPort());

Filters/Core/vtkContourFilter.h

@@ -79,6 +79,8 @@ public:
   vtkIdType GetNumberOfContours();
   void GenerateValues(int numContours, double range[2]);
   void GenerateValues(int numContours, double rangeStart, double rangeEnd);
+  void SetContourValues(const std::vector<double>& values);
+  std::vector<double> GetContourValues();
   ///@}
 
   /**
@@ -206,6 +208,16 @@ public:
   vtkBooleanMacro(FastMode, bool);
   ///@}
 
+  /**
+   * Sets the name of the input array to be used for generating
+   * the isosurfaces. This is a convenience method and it calls
+   * SetInputArrayToProcess().
+   */
+  void SetInputArray(const std::string& name)
+  {
+    this->SetInputArrayToProcess(0, 0, 0, vtkDataObject::FIELD_ASSOCIATION_POINTS, name.c_str());
+  }
+
 protected:
   vtkContourFilter();
   ~vtkContourFilter() override;
@@ -319,5 +331,36 @@ inline void vtkContourFilter::GenerateValues(int numContours, double rangeStart,
   this->ContourValues->GenerateValues(numContours, rangeStart, rangeEnd);
 }
 
+/**
+ * Convenience method to set all of the contour values at once.
+ * Loops over the vector elements and calls SetValue()
+ */
+inline void vtkContourFilter::SetContourValues(const std::vector<double>& values)
+{
+  int numContours = static_cast<int>(values.size());
+  this->SetNumberOfContours(numContours);
+  for (int i = 0; i < numContours; i++)
+  {
+    this->SetValue(i, values[i]);
+  }
+}
+
+/**
+ * Convenience method to get all of the contour values at once.
+ * The returned vector is a copy and cannot be used to modify
+ * contour values.
+ */
+inline std::vector<double> vtkContourFilter::GetContourValues()
+{
+  std::vector<double> contours;
+  int numContours = this->GetNumberOfContours();
+  contours.reserve(numContours);
+  for (int i = 0; i < numContours; i++)
+  {
+    contours.push_back(this->GetValue(i));
+  }
+  return contours;
+}
+
 VTK_ABI_NAMESPACE_END
 #endif