Python binding improvements and fixes (#583)

* Python binding improvements and fixes

* CR Fix and more decimation settings

Author: Grant Karapetyan

source/mrmeshpy/MRPythonBaseExposing.cpp

@@ -419,6 +419,8 @@ MR_ADD_PYTHON_CUSTOM_DEF( mrmeshpy, EdgeId, [] ( pybind11::module_& m )
         def( "get", &MR::EdgeId::operator int );
 } )
 
+MR_ADD_PYTHON_VEC( mrmeshpy, vectorUndirectedEdges, MR::UndirectedEdgeId )
+
 MR_ADD_PYTHON_VEC( mrmeshpy, vectorEdges, MR::EdgeId )
 
 MR_ADD_PYTHON_VEC( mrmeshpy, vectorVerts, MR::VertId )

source/mrmeshpy/MRPythonDecimate.cpp

@@ -4,16 +4,31 @@
 
 MR_ADD_PYTHON_CUSTOM_DEF( mrmeshpy, Decimate, [] ( pybind11::module_& m )
 {
+    pybind11::enum_<MR::DecimateStrategy>( m, "DecimateStrategy", "Defines the order of edge collapses inside Decimate algorithm" ).
+        value( "MinimizeError", MR::DecimateStrategy::MinimizeError, "the next edge to collapse will be the one that introduced minimal error to the surface" ).
+        value( "ShortestEdgeFirst", MR::DecimateStrategy::ShortestEdgeFirst, "the next edge to collapse will be the shortest one" );
+
     pybind11::class_<MR::DecimateSettings>( m, "DecimateSettings", "Parameters structure for decimateMesh" ).
         def( pybind11::init<>() ).
-        def_readwrite( "maxError", &MR::DecimateSettings::maxError, "stop the decimation as soon as the estimated distance deviation from the original mesh is more than this value" ). // only comment about default strategy
+        def_readwrite( "strategy", &MR::DecimateSettings::strategy ).
+        def_readwrite( "maxError", &MR::DecimateSettings::maxError, 
+            "for DecimateStrategy::MinimizeError:\n"
+            "\tstop the decimation as soon as the estimated distance deviation from the original mesh is more than this value\n"
+            "for DecimateStrategy::ShortestEdgeFirst only:\n"
+            "\tstop the decimation as soon as the shortest edge in the mesh is greater than this value" ).
+        def_readwrite( "maxEdgeLen", &MR::DecimateSettings::maxEdgeLen, "Edges longer than this value will not be collapsed (but they can appear after collapsing of shorter ones)" ).
         def_readwrite( "maxDeletedFaces", &MR::DecimateSettings::maxDeletedFaces, "Limit on the number of deleted faces" ).
         def_readwrite( "maxDeletedVertices", &MR::DecimateSettings::maxDeletedVertices, "Limit on the number of deleted vertices" ).
         def_readwrite( "maxTriangleAspectRatio", &MR::DecimateSettings::maxTriangleAspectRatio, "Maximal possible aspect ratio of a triangle introduced during decimation" ).
         def_readwrite( "stabilizer", &MR::DecimateSettings::stabilizer,
             "Small stabilizer is important to achieve good results on completely planar mesh parts,\n"
             "if your mesh is not-planer everywhere, then you can set it to zero" ).
-        def_readwrite( "region", &MR::DecimateSettings::region, "Region on mesh to be decimated, it is updated during the operation" );
+        def_readwrite("optimizeVertexPos",&MR::DecimateSettings::optimizeVertexPos,
+            "if true then after each edge collapse the position of remaining vertex is optimized to\n"
+            "minimize local shape change, if false then the edge is collapsed in one of its vertices, which keeps its position" ).
+        def_readwrite( "region", &MR::DecimateSettings::region, "Region on mesh to be decimated, it is updated during the operation" ).
+        def_readwrite( "touchBdVertices", &MR::DecimateSettings::touchBdVertices, "Whether to allow collapsing edges having at least one vertex on (region) boundary" ).
+        def_readwrite( "packMesh", &MR::DecimateSettings::packMesh, "whether to pack mesh at the end" );
 
     pybind11::class_<MR::DecimateResult>( m, "DecimateResult", "Results of decimateMesh" ).
         def( pybind11::init<>() ).

source/mrmeshpy/MRPythonIO.cpp

@@ -105,6 +105,36 @@ class PythonIstreamBuf : public std::streambuf
     std::streamsize size_;
 };
 
+// Buffer that writes in Python instead of C++
+class PythonOstreamBuf : public std::stringbuf
+{
+public:
+    PythonOstreamBuf( pybind11::object outFileHandle ) :
+        pywrite_( outFileHandle.attr( "write" ) ),
+        pyflush_( outFileHandle.attr( "flush" ) )
+    {
+    }
+    ~PythonOstreamBuf()
+    {
+        sync_();
+    }
+    int sync() override
+    {
+        sync_();
+        return 0;
+    }
+
+private:
+    pybind11::object pywrite_;
+    pybind11::object pyflush_;
+    void sync_()
+    {
+        pybind11::bytes bytes = pybind11::bytes( this->str() );
+        pywrite_( bytes );
+        pyflush_();
+    }
+};
+
 }
 
 tl::expected<MR::Mesh, std::string> pythonLoadMeshFromAnyFormat( pybind11::object fileHandle, const std::string& extension )
@@ -120,7 +150,7 @@ tl::expected<void, std::string> pythonSaveMeshToAnyFormat( const Mesh& mesh, con
 {
     if ( !( pybind11::hasattr( fileHandle, "write" ) && pybind11::hasattr( fileHandle, "flush" ) ) )
         return tl::make_unexpected( "Argument is not file handle" );
-    pybind11::detail::pythonbuf pybuf( fileHandle );
+    PythonOstreamBuf pybuf( fileHandle );
     std::ostream outfs( &pybuf );
     return MR::MeshSave::toAnySupportedFormat( mesh, outfs, extension );
 }
@@ -129,7 +159,7 @@ tl::expected<void, std::string> pythonSaveLinesToAnyFormat( const MR::Polyline3&
 {
     if ( !( pybind11::hasattr( fileHandle, "write" ) && pybind11::hasattr( fileHandle, "flush" ) ) )
         return tl::make_unexpected( "Argument is not file handle" );
-    pybind11::detail::pythonbuf pybuf( fileHandle );
+    PythonOstreamBuf pybuf( fileHandle );
     std::ostream outfs( &pybuf );
     return MR::LinesSave::toAnySupportedFormat( lines, outfs, extension );
 }
@@ -147,7 +177,7 @@ tl::expected<void, std::string> pythonSavePointCloudToAnyFormat( const PointClou
 {
     if ( !( pybind11::hasattr( fileHandle, "write" ) && pybind11::hasattr( fileHandle, "flush" ) ) )
         return tl::make_unexpected( "Argument is not file handle" );
-    pybind11::detail::pythonbuf pybuf( fileHandle );
+    PythonOstreamBuf pybuf( fileHandle );
     std::ostream outfs( &pybuf );
     return MR::PointsSave::toAnySupportedFormat( points, outfs, extension );
 }

source/mrmeshpy/MRPythonMeshExposing.cpp

@@ -88,6 +88,14 @@ MR_ADD_PYTHON_CUSTOM_DEF( mrmeshpy, Vector, [] ( pybind11::module_& m )
         def( pybind11::init<>() ).
         def_readwrite( "vec", &MR::VertMap::vec_ );
 
+    pybind11::class_<MR::WholeEdgeMap>( m, "WholeEdgeMap" ).
+        def( pybind11::init<>() ).
+        def_readwrite( "vec", &MR::WholeEdgeMap::vec_ );
+
+    pybind11::class_<MR::UndirectedEdgeMap>( m, "UndirectedEdgeMap" ).
+        def( pybind11::init<>() ).
+        def_readwrite( "vec", &MR::UndirectedEdgeMap::vec_ );
+
     pybind11::class_<MR::EdgeMap>( m, "EdgeMap" ).
         def( pybind11::init<>() ).
         def_readwrite( "vec", &MR::EdgeMap::vec_ );