Merge topic 'python-py3k-install-import'

25d44596 Relative import is required for installed VTK.
96ca3e6f Fix HAVE_ROUND-related build warnings in Visual Studio 2013

Acked-by: Kitware Robot <kwrobot@kitware.com>
Reviewed-by: Ben Boeckel <ben.boeckel@kitware.com>
Merge-request: !748

Wrapping/Python/CMakeLists.txt

@@ -166,13 +166,9 @@ if(PYTHON_EXECUTABLE)
 # Wrapping/Python/vtk/*.py
   unset(VTK_PYTHON_FILES)
   unset(VTK_PYTHON_IMPORT_ALL)
-  set(LOCAL_IMPORT_DOT ".")
-  if("${PYTHON_MAJOR_VERSION}" LESS 3)
-    set(LOCAL_IMPORT_DOT "")
-  endif()
   foreach(module ${VTK_PYTHON_MODULES})
     set(VTK_PYTHON_IMPORT_ALL
-      "${VTK_PYTHON_IMPORT_ALL}from ${LOCAL_IMPORT_DOT}${module} import *\n")
+      "${VTK_PYTHON_IMPORT_ALL}from .${module} import *\n")
     configure_file(vtk/module.py.in vtk/${module}.py @ONLY)
     list(APPEND VTK_PYTHON_FILES
       "${CMAKE_CURRENT_BINARY_DIR}/vtk/${module}.py")

Wrapping/Python/vtk/__init__.py.in

 """ This module loads the entire VTK library into its namespace.  It
 also allows one to use specific packages inside the vtk directory.."""
 
+from __future__ import absolute_import
+
 import os
 import sys
 
@@ -62,10 +64,10 @@ def vtkImageScalarTypeNameMacro(type):
   return __vtkTypeNameDict[type]
 
 # import convenience decorators
-from @LOCAL_IMPORT_DOT@util.misc import calldata_type
+from .util.misc import calldata_type
 
 # import the vtkVariant helpers
-from @LOCAL_IMPORT_DOT@util.vtkVariant import *
+from .util.vtkVariant import *
 
 # reset the dlopen flags to the original state if possible.
 if dl and (os.name == 'posix') and orig_dlopen_flags:

Wrapping/Python/vtk/module.py.in

-from @module@Python import *
+from __future__ import absolute_import
+
+try:
+    # use relative import for installed modules
+    from .@module@Python import *
+except ImportError:
+    # during build and testing, the modules will be elsewhere,
+    # e.g. in lib directory or Release/Debug config directories
+    from @module@Python import *