View source for Documentation/Nightly/Developers/Tutorials/MigrationGuide/VTK6-to-VTK7

<noinclude>__TOC__</noinclude>
==Migration guide: Transition from VTK6 to VTK7==
This section lists categories of code changes necessary to build Slicer with VTK 7.1. Each category has a short description, an example error message, a suggested upgrade path, and references to relevant commits.

Referencing this list might be helpful if Slicer extensions require updates to be compatible with VTK 7.1.

===Deprecated the vtkStreamer class hierarchy===

VTK has deprecated the vtkStreamer class hierarchy.

<b>Error message similar to:</b>

 'VTK_INTEGRATE_FORWARD' : undeclared identifier

<b>Solution:</b>

Replace lines like:

 #include "vtkStreamer.h"

with:

 #include "vtkHyperStreamline.h"

<b>References:</b>

* https://github.com/Slicer/Slicer/commit/a78fa0dc33d7c3822bff14b0e2bc403cf6ee9b31 (COMP: Update #include of deprecated vtkStreamer.h)
* https://github.com/Kitware/VTK/commit/c9f7a5e (vtkStreamer: deprecate the class hierarchy)

===Deprecated vtkMatrix4x4::operator[] method===

VTK has deprecated the <tt>vtkMatrix4x4::operator[]</tt> method.

<b>Error message similar to:</b>

 binary '[' : 'vtkMatrix4x4' does not define this operator or a conversion to a type acceptable to the predefined operator

<b>Solution:</b>

Replace lines like:

 (*mat)[i][j] = val;
 val = (*mat)[i][j];

with:

 mat->SetElement(i, j, val);
 val = mat->GetElement(i, j);

<b>References:</b>

* https://github.com/Slicer/Slicer/commit/375e69d37326d6280fea9100ba786267feae46c4 (COMP: Update usage of legacy vtkMatrix4x4 method)
* https://github.com/Kitware/VTK/commit/d9c5ca0 (Mark legacy methods as "legacy".)

===Removed vtksys/ios, vtksys/stl compatibility layers===

VTK has removed the vtksys/ios and vtksys/stl compatibility layers.

<b>Error message similar to:</b>

 Cannot open include file: 'vtksys/ios/iostream': No such file or directory

<b>Solution:</b>

Replace lines like:

 #include <vtksys/ios/iostream>
 #include <vtksys/ios/sstream>
 
 vtksys_ios::ofstream ofs;

with:

 #include <iostream>
 #include <sstream>
 
 std::ofstream ofs;

Replace lines like:

 #include <vtksys/stl/string>
 #include <vtksys/stl/vector>
 
 vtksys_stl::string str;
 vtksys_stl::vector<double> vec;

with:

 #include <string>
 #include <vector>
 
 std::string str;
 std::vector<double> vec;

<b>References:</b>
* https://github.com/msmolens/Slicer/commit/55731d6caa7811df346319fdbf6f1d7c6036a31a (COMP: Remove usage of #include <vtksys/stl/*>)
* https://github.com/Kitware/VTK/commit/eaf0f6ac1bc2f65770adf5ff6f17759485cd8072 (ENH: Remove use of include <vtksys/stl/*> and vtksys_stl::*)
* https://github.com/Kitware/VTK/commit/3ae7dd3a106d6b59380e35dfe6962a8c849316c8 (ENH: Remove use of include <vtksys/ios/*> and vtksys_ios::*)

===vtkDataArray refactored===

VTK has refactored the vtkDataArray class hierarchy.

<b>Error message similar to:</b>

 'class XXX’ has no member named ‘SetTupleValue’

<b>Solution:</b>

Replace lines like:

 array->GetTupleValue(0, val);
 array->SetTupleValue(0, val);
 array->InsertTupleValue(i, val);
 array->InsertNextTupleValue(val);

with:

 array->GetTypedTuple(0, val);
 array->SetTypedTuple(0, val);
 array->InsertTypedTuple(i, val);
 array->InsertNextTypedTuple(val);

Replace lines like:

 #include <vtkDataArrayTemplate.h>
 
 <any reference to "vtkDataArrayTemplate">

with:

 #include <vtkAOSDataArrayTemplate.h>
 
 <reference to "vtkAOSDataArrayTemplate">

<b>References:</b>
* https://github.com/msmolens/Slicer/commit/fedb69d0e622d00c81102461ab13909f96341528 (COMP: Update usage of deprecated vtkDataArrayTemplate)
* https://github.com/Kitware/VTK/commit/06e98d0 (Replace vtkDataArrayTemplate with vtkAoSDataArrayTemplate.)
* https://github.com/Kitware/VTK/commit/893fb6e (Refactor data array APIs.)
* http://public.kitware.com/pipermail/vtkusers/2016-May/095388.html ([vtkusers] Wiki examples fail to build due to no InsertNextTypedTuple)
* https://github.com/Kitware/VTK/blob/master/Documentation/Doxygen/ChangesVTK-7-1.md#vtkdataarray-refactor-vtkarraydispatch-and-related-tools

===Deprecated pipeline update methods===

VTK has deprecated and replaced certain pipeline update methods.

<b>Error message similar to:</b>

 'class XXX’ has no member named ‘SetUpdateExtent’

<b>Solution:</b>

Follow suggestions in VTK changelog: https://github.com/Kitware/VTK/blob/master/Documentation/Doxygen/ChangesVTK-7-1.md#pipeline-update-methods

<b>References:</b>

* https://github.com/msmolens/Slicer/commit/f1b93c432dd9ab3f93987c656e3947b90a7cdb45 (COMP: Update usage of deprecated SetUpdateExtent methods)
* https://github.com/Kitware/VTK/commit/f020ebb

===Updated Python wrapping===

VTK has updated its Python wrapping to support Python 3 and to wrap more code by default.

<b>Symptoms:</b>

Compile or link error while building a Python-wrapped class or library.

<b>Solution 1:</b>

In <tt>CMakeLists.txt</tt>, add the <tt>WRAP_EXCLUDE_PYTHON</tt> property anywhere that the <tt>WRAP_EXCLUDE</tt> property is defined on source files.

<b>Solution 2:</b>

Replace lines of code like:

 //BTX
 ...
 //ETX

with:

 #ifndef __VTK_WRAP__
 ...
 #endif // __VTK_WRAP__

<b>References:</b>

* https://github.com/msmolens/Slicer/commit/10a69c987dcdd4abdbaa74afad22f4af3c16b417 (COMP: Update usage of WRAP_EXCLUDE for Python)
* https://github.com/msmolens/Slicer/commit/d5ca934951cf411c2a4b9b56de533a07e265dcaf (COMP: Update excluding singleton intializers for wrapping)
* https://github.com/Kitware/VTK/commit/e6f75b9 (Wrap many more classes with python.)
* https://github.com/Kitware/VTK/commit/55878a2 (Manual search & destroy of (B|E)TX)
* http://www.vtk.org/Wiki/VTK/Python_Wrapper_Enhancement
* http://www.vtk.org/Wiki/VTK/Python_Wrapping_FAQ

===vtkMTimeType===

VTK introduced a specific type—<tt>vtkMTimeType</tt>—to be used for <tt>vtkObject</tt> modified time (MTime).

<b>Error message similar to:</b>

 vtkDiffusionTensorGlyph::GetMTime': overriding virtual function return type differs and is not covariant from 'vtkObject::GetMTime'

<b>Solution:</b>

Update code that uses <tt>unsigned long</tt> or <tt>unsigned long int</tt> for modified times to use <tt>vtkMTimeType</tt>.

<b>References:</b>

* https://gitlab.kitware.com/vtk/vtk/merge_requests/1790

===vtkStandardNewMacro expects vtkObjectFactory.h===

<b>Error message similar to:</b>

  expected constructor, destructor, or type conversion before ‘;’ token
    vtkStandardNewMacro(vtkSlicerModelClipLogic);

<b>Solution:</b>

Add:

  #include <vtkObjectFactory.h>