ENH: added AddBlueprint() to SuperElastixFilter

Modules/Core/Filter/include/selxSuperElastixFilter.h

@@ -63,8 +63,11 @@ public:
   typedef BlueprintType::Pointer                                      BlueprintPointer;
   typedef BlueprintType::ConstPointer                                 BlueprintConstPointer;
 
-  // TODO: Make const-correct
-  itkSetObjectMacro( Blueprint, BlueprintType )
+  // Setting a Blueprint creates a pipeline such that when SuperElastixFilter is updated it checks if the blueprint has been modified and if so, SuperElastixFilter resets its internals and start building the blueprint from scratch
+  itkSetObjectMacro(Blueprint, BlueprintType);
+
+  // Adding a Blueprint composes SuperElastixFilter' internal blueprint (accessible by Set/Get Blueprint) with the otherBlueprint.
+  void AddBlueprint(BlueprintPointer otherBlueprint);
 
   AnyFileReaderType::Pointer GetInputFileReader( const DataObjectIdentifierType & );
 

Modules/Core/Filter/src/selxSuperElastixFilter.cxx

@@ -52,7 +52,14 @@ m_AllUniqueComponents(false)
   this->SetRequiredInputNames({});
 } // end Constructor
 
-
+void
+SuperElastixFilter
+::AddBlueprint(BlueprintPointer otherBlueprint)
+{
+  auto blueprint_internals = this->m_Blueprint->Get();
+  blueprint_internals->ComposeWith(otherBlueprint->Get());
+  this->m_Blueprint->Set(blueprint_internals);
+}
 /**
 * ********************* GenerateOutputInformation *********************
 */
@@ -76,13 +83,20 @@ SuperElastixFilter
   // are passed further down stream.
   // Eventually configuration boils down to a while loop that repeatedly tries to narrow down
   // the component selectors until no more unique components can be found.
-    if (!this->m_Blueprint)
-    {
-      itkExceptionMacro(<< "Setting a Blueprint is required first.")
-    }
+  if (!this->m_Blueprint)
+  {
+    itkExceptionMacro(<< "Setting a Blueprint is required first.")
+  }
+  if (this->m_Blueprint->Modified())
+  {
+    // Was m_Blueprint modified by Set() or by AddBlueprint?
+
+  }
+
 
     this->m_NetworkBuilder->AddBlueprint(this->m_Blueprint->Get());
     this->m_AllUniqueComponents = this->m_NetworkBuilder->Configure();
+    
   if (this->m_BlueprintConnectionModified == true)
   {
 //TODO: