Changes between Version 9 and Version 10 of FDORfc66

Timestamp:

May 9, 2013, 3:00:37 AM (11 years ago)

Author:

christinebao

Comment:

--

FDORfc66

@@ -57 +57 @@
 The caller can make a class inherit from !FdoCoordinateSystemTransform and implement real !CoordinateSystemTransform(...) function, set the instance to !FdoXmlFeatureFlags, and the feature data is transformed.
 
+== Managed FDO API ==
+
+The managed FDO API is a little tricky because it needs to allow the caller create managed child class and implement the coordinate system transformation in its own child class. A solution is to make a VirtualFdoCoordinateSystemTransform which inherits from VirtualObject, a template in OSGeo.Fdo.Common for forwarding unmanaged methods to managed one:
+
+{{{
+class VirtualFdoCoordinateSystemTransform : public VirtualObject <NAMESPACE_OSGEO_FDO_XML::CoordinateSystemTransform, FdoCoordinateSystemTransform>
+{
+public:
+        FdoIDirectPosition* CoordinateSystemTransform(FdoIDirectPosition* sourceGeometry);
+
+private:
+        enum WrapperCallBits
+        {
+                TransformBit              = 0x01,
+        };
+        mutable FdoInt32 wrapperCallBits;
+};
+
+FdoIDirectPosition* VirtualFdoCoordinateSystemTransform::CoordinateSystemTransform(FdoIDirectPosition* sourceGeometry)
+{
+        if (!WrapperCallWrapper::IsCalling(wrapperCallBits, TransformBit))
+        {
+                WrapperCallWrapper ctx(wrapperCallBits, TransformBit);
+                
+        NAMESPACE_OSGEO_GEOMETRY::IDirectPosition ^managedSourceGeometry =  gcnew NAMESPACE_OSGEO_GEOMETRY::IDirectPositionImp(IntPtr(sourceGeometry), true);
+                NAMESPACE_OSGEO_GEOMETRY::IDirectPositionImp^ destGeometry = static_cast<NAMESPACE_OSGEO_GEOMETRY::IDirectPositionImp^>(GetWrapper()->CoordinateSystemTransformPosition(managedSourceGeometry));
+                return static_cast<FdoIDirectPosition*>(destGeometry->GetDisposableObject().ToPointer());
+        }
+        else
+        {
+                return 0;
+        }
+}
+}}}
+
+And the managed !CoordinateSystemTransform can be initialized in this way:
+
+{{{
+NAMESPACE_OSGEO_FDO_XML::CoordinateSystemTransform::CoordinateSystemTransform() : Disposable(IntPtr(new VirtualFdoCoordinateSystemTransform()), true)
+{
+        static_cast<VirtualFdoCoordinateSystemTransform*>(GetImpObj())->SetWrapper(this);
+}
+}}}
+
+By doing this the child class of !CoordinateSystemTransform can do the coordinate system transformation.
+
+Above is pseudo code as a reference. Currently there is no concrete requirement in managed side, so the managed API is not added and tested.
+
 == Implications ==