BUG: Set number of targets for FMUG image filter

Set the number of targets ivar to the appropriate value for the
`itk::FastMarchingUpwindGradientImageFilter` class.

The existing implementation was not setting the `m_NumberOfTargets` ivar
to the appropriate values depending on the `m_TargetReachedMode` value.

Ensure that the a sufficien number of target points exists for the
desired `m_TargetReachedMode`.

Exercise and test all possibilities.

Author: jhlegarreta

Modules/Filtering/FastMarching/include/itkFastMarchingUpwindGradientImageFilter.h

@@ -161,23 +161,50 @@ class ITK_TEMPLATE_EXPORT FastMarchingUpwindGradientImageFilter : public FastMar
   SetTargetReachedModeToNoTargets()
   {
     this->SetTargetReachedMode(NoTargets);
+    m_NumberOfTargets = 0;
   }
   void
   SetTargetReachedModeToOneTarget()
   {
+    if (!m_TargetPoints || m_TargetPoints->Size() == 0)
+    {
+      itkExceptionMacro(<< "No target point set. Cannot set the target reached mode.")
+    }
     this->SetTargetReachedMode(OneTarget);
+    m_NumberOfTargets = 1;
   }
   void
   SetTargetReachedModeToSomeTargets(SizeValueType numberOfTargets)
   {
+    if (!m_TargetPoints || m_TargetPoints->Size() == 0)
+    {
+      itkExceptionMacro(<< "No target point set. Cannot set the target reached mode.")
+    }
+
+    SizeValueType availableNumberOfTargets = m_TargetPoints->Size();
+    if (numberOfTargets > availableNumberOfTargets)
+    {
+      itkExceptionMacro(<< "Not enought target points: Available: " << availableNumberOfTargets
+                        << "; Requested: " << numberOfTargets);
+    }
     this->SetTargetReachedMode(SomeTargets);
     m_NumberOfTargets = numberOfTargets;
   }
 
   void
   SetTargetReachedModeToAllTargets()
   {
+    if (!m_TargetPoints || m_TargetPoints->Size() == 0)
+    {
+      itkExceptionMacro(<< "No target point set. Cannot set the target reached mode.")
+    }
+
     this->SetTargetReachedMode(AllTargets);
+    if (m_TargetPoints->Size() == 0)
+    {
+      itkExceptionMacro(<< "No target point set. Cannot set the target reached mode.")
+    }
+    m_NumberOfTargets = m_TargetPoints->Size();
   }
 
   /** Get the number of targets. */

Modules/Filtering/FastMarching/test/itkFastMarchingUpwindGradientTest.cxx

@@ -53,6 +53,15 @@ itkFastMarchingUpwindGradientTest(int, char *[])
   ITK_EXERCISE_BASIC_OBJECT_METHODS(marcher, FastMarchingUpwindGradientImageFilter, FastMarchingImageFilter);
 
 
+  // Test exceptions
+  ITK_TRY_EXPECT_EXCEPTION(marcher->SetTargetReachedModeToOneTarget());
+
+  itk::SizeValueType numberOfTargets = 0;
+  ITK_TRY_EXPECT_EXCEPTION(marcher->SetTargetReachedModeToSomeTargets(numberOfTargets));
+
+  ITK_TRY_EXPECT_EXCEPTION(marcher->SetTargetReachedModeToAllTargets());
+
+
   //   ShowProgressObject progressWatch(marcher);
   //   itk::SimpleMemberCommand<ShowProgressObject>::Pointer command;
   //   command = itk::SimpleMemberCommand<ShowProgressObject>::New();
@@ -241,14 +250,23 @@ itkFastMarchingUpwindGradientTest(int, char *[])
   marcher->SetTargetPoints(targetPoints);
   ITK_TEST_SET_GET_VALUE(targetPoints, marcher->GetTargetPoints());
 
+  // The target reached mode is set to no targets by default
+  ITK_TEST_SET_GET_VALUE(FloatFMType::NoTargets, marcher->GetTargetReachedMode());
+
+  numberOfTargets = 0;
+  ITK_TEST_EXPECT_EQUAL(numberOfTargets, marcher->GetNumberOfTargets());
+
   // Stop the algorithm when ONE of the targets has been reached.
   marcher->SetTargetReachedModeToOneTarget();
   ITK_TEST_SET_GET_VALUE(FloatFMType::OneTarget, marcher->GetTargetReachedMode());
 
-  marcher->Update();
+  numberOfTargets = 1;
+  ITK_TEST_EXPECT_EQUAL(numberOfTargets, marcher->GetNumberOfTargets());
+
+  ITK_TRY_EXPECT_NO_EXCEPTION(marcher->Update());
 
-  VectorType::size_type reachedTargetPointCount = 1;
-  ITK_TEST_EXPECT_EQUAL(reachedTargetPointCount, marcher->GetReachedTargetPoints()->Size());
+
+  ITK_TEST_EXPECT_EQUAL(numberOfTargets, marcher->GetReachedTargetPoints()->Size());
 
   // Find the smallest reaching time of the TargetPoints.  This is the time of the closest
   // TargetPoint.
@@ -270,15 +288,32 @@ itkFastMarchingUpwindGradientTest(int, char *[])
     passed = false;
   }
 
+  // Now stop the algorithm once SOME of the targets have been reached.
+  numberOfTargets = targetPoints->Size() + 1;
+  ITK_TRY_EXPECT_EXCEPTION(marcher->SetTargetReachedModeToSomeTargets(numberOfTargets));
+
+  numberOfTargets = targetPoints->Size() - 1;
+  marcher->SetTargetReachedModeToSomeTargets(numberOfTargets);
+  ITK_TEST_SET_GET_VALUE(FloatFMType::SomeTargets, marcher->GetTargetReachedMode());
+
+  ITK_TEST_EXPECT_EQUAL(numberOfTargets, marcher->GetNumberOfTargets());
+
+  ITK_TRY_EXPECT_NO_EXCEPTION(marcher->Update());
+
+
+  ITK_TEST_EXPECT_EQUAL(numberOfTargets, marcher->GetReachedTargetPoints()->Size());
 
   // Now stop the algorithm once ALL of the targets have been reached.
   marcher->SetTargetReachedModeToAllTargets();
   ITK_TEST_SET_GET_VALUE(FloatFMType::AllTargets, marcher->GetTargetReachedMode());
 
-  marcher->Update();
+  numberOfTargets = targetPoints->Size();
+  ITK_TEST_EXPECT_EQUAL(numberOfTargets, marcher->GetNumberOfTargets());
+
+  ITK_TRY_EXPECT_NO_EXCEPTION(marcher->Update());
+
 
-  reachedTargetPointCount = marcher->GetTargetPoints()->Size();
-  ITK_TEST_EXPECT_EQUAL(reachedTargetPointCount, marcher->GetReachedTargetPoints()->Size());
+  ITK_TEST_EXPECT_EQUAL(numberOfTargets, marcher->GetReachedTargetPoints()->Size());
 
   // Find the largest reaching time of the TargetPoints.  This is the largest time of
   // all of the target points.