Check for matplotlib at runtime.

This change allows the RenderingMatplotlib module to be built without
finding matplotlib at configure time.

Change-Id: Iee352157d533cdf0bd7a23fcd0807b4dd6547c89

Rendering/Matplotlib/CMakeLists.txt

-# Check that matplotlib is available:
-execute_process(COMMAND ${PYTHON_EXECUTABLE} -c "import matplotlib"
-  RESULT_VARIABLE IMPORT_MATPLOTLIB_EXITCODE
-  OUTPUT_VARIABLE IMPORT_MATPLOTLIB_OUTPUT
-  ERROR_VARIABLE IMPORT_MATPLOTLIB_ERROR
-  )
-set(MATPLOTLIB_FOUND FALSE)
-if(${IMPORT_MATPLOTLIB_EXITCODE} EQUAL 0)
-  set(MATPLOTLIB_FOUND TRUE)
-endif()
-
-if(NOT MATPLOTLIB_FOUND)
-  message(FATAL_ERROR "Matplotlib not found! ('${PYTHON_EXECUTABLE} -c \"import matplotlib\"' failed.)")
-endif()
-
 set(Module_SRCS
   vtkMatplotlibMathTextUtilities.cxx
   ${CMAKE_CURRENT_BINARY_DIR}/${vtk-module}ObjectFactory.cxx

Rendering/Matplotlib/Testing/Cxx/CMakeLists.txt

-if(VTK_GHOSTSCRIPT_EXECUTABLE AND VTK_DATA_ROOT)
-  set(GL2PSTests
-    TestGL2PSMathTextActor.cxx
-    TestGL2PSMathTextActor3D.cxx
-    TestGL2PSMathTextOutput.cxx
-    TestGL2PSMathTextScaling.cxx
+# Check that matplotlib is available:
+execute_process(COMMAND ${PYTHON_EXECUTABLE} -c "import matplotlib"
+  RESULT_VARIABLE IMPORT_MATPLOTLIB_EXITCODE
+  OUTPUT_VARIABLE IMPORT_MATPLOTLIB_OUTPUT
+  ERROR_VARIABLE IMPORT_MATPLOTLIB_ERROR
   )
+set(MATPLOTLIB_FOUND FALSE)
+if(${IMPORT_MATPLOTLIB_EXITCODE} EQUAL 0)
+  set(MATPLOTLIB_FOUND TRUE)
 endif()
 
-if(VTK_DATA_ROOT)
-  # add tests that require data
-  set(MyTests
-    TestContextMathTextImage.cxx
-    TestMathTextActor.cxx
-    TestMathTextActor3D.cxx
-    TestRenderString.cxx
-    TestStringToPath.cxx
-    TestIndexedLookupScalarBar.cxx
-    ${GL2PSTests}
-    ${MixedTests}
+if(NOT MATPLOTLIB_FOUND)
+  message("Matplotlib not found! MathText rendering will not be available until it is installed. Disabling tests.")
+endif()
+
+if(MATPLOTLIB_FOUND)
+  if(VTK_GHOSTSCRIPT_EXECUTABLE AND VTK_DATA_ROOT)
+    set(GL2PSTests
+      TestGL2PSMathTextActor.cxx
+      TestGL2PSMathTextActor3D.cxx
+      TestGL2PSMathTextOutput.cxx
+      TestGL2PSMathTextScaling.cxx
     )
+  endif()
+
+  if(VTK_DATA_ROOT)
+    # add tests that require data
+    set(MyTests
+      TestContextMathTextImage.cxx
+      TestMathTextActor.cxx
+      TestMathTextActor3D.cxx
+      TestRenderString.cxx
+      TestStringToPath.cxx
+      TestIndexedLookupScalarBar.cxx
+      ${GL2PSTests}
+      )
+  endif()
 endif()
 
 # Use the testing object factory, to reduce boilerplate code in tests.

Rendering/Matplotlib/vtkMatplotlibMathTextUtilities.cxx

@@ -64,12 +64,46 @@ public:
 };
 
 //----------------------------------------------------------------------------
-vtkObjectFactoryNewMacro(vtkMatplotlibMathTextUtilities)
+vtkMatplotlibMathTextUtilities::Availablity
+vtkMatplotlibMathTextUtilities::MPLMathTextAvailable =
+    vtkMatplotlibMathTextUtilities::NOT_TESTED;
+
+//----------------------------------------------------------------------------
+vtkMatplotlibMathTextUtilities* vtkMatplotlibMathTextUtilities::New()
+{
+  // Attempt to import matplotlib to check for availability
+  switch (vtkMatplotlibMathTextUtilities::MPLMathTextAvailable)
+    {
+    default:
+    case vtkMatplotlibMathTextUtilities::UNAVAILABLE:
+      return NULL;
+    case vtkMatplotlibMathTextUtilities::AVAILABLE:
+      break;
+    case vtkMatplotlibMathTextUtilities::NOT_TESTED:
+      Py_Initialize();
+      if (PyErr_Occurred() ||
+          !PyImport_ImportModule("matplotlib") ||
+          PyErr_Occurred())
+        {
+        vtkMatplotlibMathTextUtilities::MPLMathTextAvailable = UNAVAILABLE;
+        }
+      else
+        {
+        vtkMatplotlibMathTextUtilities::MPLMathTextAvailable = AVAILABLE;
+        }
+      if (vtkMatplotlibMathTextUtilities::MPLMathTextAvailable == UNAVAILABLE)
+        {
+        return NULL;
+        }
+      break;
+    }
+  VTK_OBJECT_FACTORY_NEW_BODY(vtkMatplotlibMathTextUtilities)
+}
+vtkInstantiatorNewMacro(vtkMatplotlibMathTextUtilities)
 
 //----------------------------------------------------------------------------
 vtkMatplotlibMathTextUtilities::vtkMatplotlibMathTextUtilities()
-  : Superclass(), PythonIsInitialized(false), MaskParser(NULL),
-    PathParser(NULL), FontPropertiesClass(NULL)
+  : Superclass(), MaskParser(NULL), PathParser(NULL), FontPropertiesClass(NULL)
 {
 }
 
@@ -79,32 +113,12 @@ vtkMatplotlibMathTextUtilities::~vtkMatplotlibMathTextUtilities()
   Py_XDECREF(this->MaskParser);
   Py_XDECREF(this->PathParser);
   Py_XDECREF(this->FontPropertiesClass);
-  if (this->PythonIsInitialized)
-    {
-    Py_Finalize();
-    }
-}
-
-//----------------------------------------------------------------------------
-bool vtkMatplotlibMathTextUtilities::InitializePython()
-{
-  if (this->PythonIsInitialized)
-    {
-    return true;
-    }
-  Py_Initialize();
-  this->PythonIsInitialized = !this->CheckForError();
-  return this->PythonIsInitialized;
+  Py_Finalize();
 }
 
 //----------------------------------------------------------------------------
 bool vtkMatplotlibMathTextUtilities::InitializeMaskParser()
 {
-  if (!this->InitializePython())
-    {
-    return false;
-    }
-
   SmartPyObject mplMathTextLib(PyImport_ImportModule("matplotlib.mathtext"));
   if (this->CheckForError(mplMathTextLib.GetPointer()))
     {
@@ -133,11 +147,6 @@ bool vtkMatplotlibMathTextUtilities::InitializeMaskParser()
 //----------------------------------------------------------------------------
 bool vtkMatplotlibMathTextUtilities::InitializePathParser()
 {
-  if (!this->InitializePython())
-    {
-    return false;
-    }
-
   SmartPyObject mplTextPathLib(PyImport_ImportModule("matplotlib.textpath"));
   if (this->CheckForError(mplTextPathLib.GetPointer()))
     {
@@ -164,11 +173,6 @@ bool vtkMatplotlibMathTextUtilities::InitializePathParser()
 //----------------------------------------------------------------------------
 bool vtkMatplotlibMathTextUtilities::InitializeFontPropertiesClass()
 {
-  if (!this->InitializePython())
-    {
-    return false;
-    }
-
   SmartPyObject mplFontManagerLib(
         PyImport_ImportModule("matplotlib.font_manager"));
   if (this->CheckForError(mplFontManagerLib.GetPointer()))
@@ -779,7 +783,6 @@ void vtkMatplotlibMathTextUtilities::PrintSelf(ostream &os, vtkIndent indent)
 {
   this->Superclass::PrintSelf(os, indent);
 
-  os << indent << "PythonIsInitialized: " << this->PythonIsInitialized << endl;
   os << indent << "MaskParser: " << this->MaskParser << endl;
   os << indent << "PathParser: " << this->PathParser << endl;
   os << indent << "FontPropertiesClass: " << this->FontPropertiesClass << endl;

Rendering/Matplotlib/vtkMatplotlibMathTextUtilities.h

@@ -59,7 +59,6 @@ protected:
   vtkMatplotlibMathTextUtilities();
   virtual ~vtkMatplotlibMathTextUtilities();
 
-  bool InitializePython();
   bool InitializeMaskParser();
   bool InitializePathParser();
   bool InitializeFontPropertiesClass();
@@ -72,7 +71,6 @@ protected:
   // the vtkTextProperty tprop.
   PyObject * GetFontProperties(vtkTextProperty *tprop);
 
-  bool PythonIsInitialized;
   PyObject *MaskParser;
   PyObject *PathParser;
   PyObject *FontPropertiesClass;
@@ -81,6 +79,16 @@ protected:
   // origin and calculate the bounding box
   void RotateCorners(double angleDeg, double corners[4][2], double bbox[4]);
 
+  // Description:
+  // Used for runtime checking of matplotlib's mathtext availability.
+  enum Availablity
+    {
+    NOT_TESTED = 0,
+    AVAILABLE,
+    UNAVAILABLE
+    };
+  static Availablity MPLMathTextAvailable;
+
 private:
   vtkMatplotlibMathTextUtilities(const vtkMatplotlibMathTextUtilities&); // Not implemented.
   void operator=(const vtkMatplotlibMathTextUtilities&); // Not implemented.