add eigen2support Transform typedefs, add Eigen2To3 section on Transform

Eigen/Eigen2Support

@@ -50,6 +50,7 @@ namespace Eigen {
 #include "src/Eigen2Support/Block.h"
 #include "src/Eigen2Support/VectorBlock.h"
 #include "src/Eigen2Support/Minor.h"
+#include "src/Eigen2Support/Transform.h"
 
 
 } // namespace Eigen

Eigen/src/Eigen2Support/Transform.h

@@ -0,0 +1,37 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2010 Benoit Jacob <jacob.benoit.1@gmail.com>
+//
+// Eigen is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 3 of the License, or (at your option) any later version.
+//
+// Alternatively, you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License and a copy of the GNU General Public License along with
+// Eigen. If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef EIGEN_TRANSFORM2_H
+#define EIGEN_TRANSFORM2_H
+
+/** \ingroup Geometry_Module */
+typedef Projective2f Transform2f;
+/** \ingroup Geometry_Module */
+typedef Projective2d Transform2d;
+/** \ingroup Geometry_Module */
+typedef Projective3f Transform3f;
+/** \ingroup Geometry_Module */
+typedef Projective3d Transform3d;
+
+#endif // EIGEN_TRANSFORM2_H

doc/A05_PortingFrom2To3.dox

@@ -7,6 +7,7 @@ and gives tips to help porting your application from Eigen2 to Eigen3.
 
 \b Table \b of \b contents
   - \ref CompatibilitySupport
+  - \ref Using
   - \ref VectorBlocks
   - \ref Corners
   - \ref CoefficientWiseOperations
@@ -14,7 +15,7 @@ and gives tips to help porting your application from Eigen2 to Eigen3.
   - \ref TriangularSolveInPlace
   - \ref Decompositions
   - \ref LinearSolvers
-  - \ref Using
+  - \ref Transform
   - \ref LazyVsNoalias
   - \ref AlignMacros
   - \ref AlignedMap
@@ -23,6 +24,13 @@ and gives tips to help porting your application from Eigen2 to Eigen3.
 
 In order to ease the switch from Eigen2 to Eigen3, Eigen3 features a compatibility mode which can be enabled by defining the EIGEN2_SUPPORT preprocessor token \b before including any Eigen header (typically it should be set in your project options).
 
+\section Using The USING_PART_OF_NAMESPACE_EIGEN macro
+
+The USING_PART_OF_NAMESPACE_EIGEN macro has been removed. In Eigen 3, just do:
+\code
+using namespace Eigen;
+\endcode
+
 \section VectorBlocks Vector blocks
 
 <table class="manual">
@@ -219,12 +227,20 @@ the selfadjointView API allows you to select the \n
 triangular part to work on</td></tr>
 </table>
 
-\section Using The USING_PART_OF_NAMESPACE_EIGEN macro
+\section Transform The Transform class
 
-The USING_PART_OF_NAMESPACE_EIGEN macro has been removed. In Eigen 3, just do:
-\code
-using namespace Eigen;
-\endcode
+In Eigen 2, the Transform class didn't really know whether it was a projective or affine transformation. In Eigen 3, it takes a new \a Mode template parameter, which indicates whether it's \a Projective or \a Affine transform. The default is \a Projective.
+
+The Transform3f (etc) typedefs are no more. In Eigen 3, the Transform typedefs explicitly refer to the \a Projective and \a Affine modes:
+
+<table class="manual">
+<tr><th>Eigen 2</th><th>Eigen 3</th><th>Notes</th></tr>
+<tr>
+  <td> Transform3f </td>
+  <td> Affine3f or Projective3f </td>
+  <td> Of course 3f is just an example here </td>
+</tr>
+</table>
 
 
 \section LazyVsNoalias Lazy evaluation and noalias