Add support for serializing transform contexts

qgis · Dec 15, 2017 · 1013c0b · 1013c0b
1 parent 3d1b8ae
commit 1013c0b
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Showing 4 changed files with 169 additions and 1 deletion.
diff --git a/python/core/qgscoordinatetransformcontext.sip b/python/core/qgscoordinatetransformcontext.sip
@@ -11,6 +11,7 @@
 
 
 
+
 class QgsCoordinateTransformContext
 {
 %Docstring
@@ -168,6 +169,19 @@ class QgsCoordinateTransformContext
  :rtype: QPair< int, int >
 %End
 
+    void readXml( const QDomElement &element, const QDomDocument &document, const QgsReadWriteContext &context );
+%Docstring
+ Reads the context's state from a DOM ``element``.
+.. seealso:: writeXml()
+%End
+
+    void writeXml( QDomElement &element, QDomDocument &document, const QgsReadWriteContext &context ) const;
+%Docstring
+ Writes the context's state to a DOM ``element``.
+.. seealso:: readXml()
+%End
+
+
 };
 
 

diff --git a/src/core/qgscoordinatetransformcontext.cpp b/src/core/qgscoordinatetransformcontext.cpp
@@ -147,3 +147,108 @@ QPair<int, int> QgsCoordinateTransformContext::calculateDatumTransforms( const Q
   d->mLock.unlock();
   return qMakePair( srcTransform, destTransform );
 }
+
+void QgsCoordinateTransformContext::readXml( const QDomElement &element, const QDomDocument &, const QgsReadWriteContext & )
+{
+  d.detach();
+  d->mLock.lockForWrite();
+
+  d->mSourceDestDatumTransforms.clear();
+  d->mSourceDatumTransforms.clear();
+  d->mDestDatumTransforms.clear();
+
+  const QDomNodeList contextNodes = element.elementsByTagName( QStringLiteral( "transformContext" ) );
+  if ( contextNodes.count() < 1 )
+  {
+    d->mLock.unlock();
+    return;
+  }
+
+  const QDomElement contextElem = contextNodes.at( 0 ).toElement();
+
+  // src/dest transforms
+  const QDomNodeList srcDestNodes = contextElem.elementsByTagName( QStringLiteral( "srcDest" ) );
+  for ( int i = 0; i < srcDestNodes.size(); ++i )
+  {
+    const QDomElement transformElem = srcDestNodes.at( i ).toElement();
+    QString key1 = transformElem.attribute( QStringLiteral( "source" ) );
+    QString key2 = transformElem.attribute( QStringLiteral( "dest" ) );
+    bool ok = false;
+    int value1 = transformElem.attribute( QStringLiteral( "sourceTransform" ) ).toInt( &ok );
+    bool ok2 = false;
+    int value2 = transformElem.attribute( QStringLiteral( "destTransform" ) ).toInt( &ok2 );
+    if ( ok && ok2 )
+    {
+      d->mSourceDestDatumTransforms.insert( qMakePair( key1, key2 ), qMakePair( value1, value2 ) );
+    }
+  }
+
+  // src transforms
+  const QDomNodeList srcNodes = contextElem.elementsByTagName( QStringLiteral( "source" ) );
+  for ( int i = 0; i < srcNodes .size(); ++i )
+  {
+    const QDomElement transformElem = srcNodes.at( i ).toElement();
+    QString key = transformElem.attribute( QStringLiteral( "crs" ) );
+    bool ok = false;
+    int value = transformElem.attribute( QStringLiteral( "transform" ) ).toInt( &ok );
+    if ( ok )
+    {
+      d->mSourceDatumTransforms.insert( key, value );
+    }
+  }
+
+  // dest transforms
+  const QDomNodeList destNodes = contextElem.elementsByTagName( QStringLiteral( "dest" ) );
+  for ( int i = 0; i < destNodes.size(); ++i )
+  {
+    const QDomElement transformElem = destNodes.at( i ).toElement();
+    QString key = transformElem.attribute( QStringLiteral( "crs" ) );
+    bool ok = false;
+    int value = transformElem.attribute( QStringLiteral( "transform" ) ).toInt( &ok );
+    if ( ok )
+    {
+      d->mDestDatumTransforms.insert( key, value );
+    }
+  }
+
+  d->mLock.unlock();
+}
+
+void QgsCoordinateTransformContext::writeXml( QDomElement &element, QDomDocument &document, const QgsReadWriteContext & ) const
+{
+  d->mLock.lockForRead();
+
+  QDomElement contextElem = document.createElement( QStringLiteral( "transformContext" ) );
+
+  //src/dest transforms
+  for ( auto it = d->mSourceDestDatumTransforms.constBegin(); it != d->mSourceDestDatumTransforms.constEnd(); ++ it )
+  {
+    QDomElement transformElem = document.createElement( QStringLiteral( "srcDest" ) );
+    transformElem.setAttribute( QStringLiteral( "source" ), it.key().first );
+    transformElem.setAttribute( QStringLiteral( "dest" ), it.key().second );
+    transformElem.setAttribute( QStringLiteral( "sourceTransform" ), it.value().first );
+    transformElem.setAttribute( QStringLiteral( "destTransform" ), it.value().second );
+    contextElem.appendChild( transformElem );
+  }
+
+  // src transforms
+  for ( auto it = d->mSourceDatumTransforms.constBegin(); it != d->mSourceDatumTransforms.constEnd(); ++ it )
+  {
+    QDomElement transformElem = document.createElement( QStringLiteral( "source" ) );
+    transformElem.setAttribute( QStringLiteral( "crs" ), it.key() );
+    transformElem.setAttribute( QStringLiteral( "transform" ), it.value() );
+    contextElem.appendChild( transformElem );
+  }
+
+  // dest transforms
+  for ( auto it = d->mDestDatumTransforms.constBegin(); it != d->mDestDatumTransforms.constEnd(); ++ it )
+  {
+    QDomElement transformElem = document.createElement( QStringLiteral( "dest" ) );
+    transformElem.setAttribute( QStringLiteral( "crs" ), it.key() );
+    transformElem.setAttribute( QStringLiteral( "transform" ), it.value() );
+    contextElem.appendChild( transformElem );
+  }
+
+  element.appendChild( contextElem );
+  d->mLock.unlock();
+}
diff --git a/src/core/qgscoordinatetransformcontext.h b/src/core/qgscoordinatetransformcontext.h
@@ -22,6 +22,8 @@
 #include "qgis.h"
 #include "qgscoordinatetransformcontext_p.h"
 
+class QgsReadWriteContext;
+
 /***************************************************************************
  * This class is considered CRITICAL and any change MUST be accompanied with
  * full unit tests in testqgsfeature.cpp.
@@ -175,6 +177,19 @@ class CORE_EXPORT QgsCoordinateTransformContext
     QPair< int, int > calculateDatumTransforms( const QgsCoordinateReferenceSystem &source,
         const QgsCoordinateReferenceSystem &destination ) const;
 
+    /**
+     * Reads the context's state from a DOM \a element.
+     * \see writeXml()
+     */
+    void readXml( const QDomElement &element, const QDomDocument &document, const QgsReadWriteContext &context );
+
+    /**
+     * Writes the context's state to a DOM \a element.
+     * \see readXml()
+     */
+    void writeXml( QDomElement &element, QDomDocument &document, const QgsReadWriteContext &context ) const;
+
+
   private:
 
     QExplicitlySharedDataPointer<QgsCoordinateTransformContextPrivate> d;

diff --git a/tests/src/python/test_qgscoordinatetransformcontext.py b/tests/src/python/test_qgscoordinatetransformcontext.py
@@ -15,8 +15,10 @@
 import qgis  # NOQA
 
 from qgis.core import (QgsCoordinateReferenceSystem,
-                       QgsCoordinateTransformContext)
+                       QgsCoordinateTransformContext,
+                       QgsReadWriteContext)
 from qgis.testing import start_app, unittest
+from qgis.PyQt.QtXml import QDomDocument
 
 app = start_app()
 
@@ -180,6 +182,38 @@ def testCalculate(self):
                                                           QgsCoordinateReferenceSystem('EPSG:3111')),
                          (1, -1))
 
+    def testWriteReadXml(self):
+        # setup a context
+        context = QgsCoordinateTransformContext()
+        self.assertTrue(context.addSourceDatumTransform(QgsCoordinateReferenceSystem('EPSG:3111'), 1))
+        self.assertTrue(context.addSourceDatumTransform(QgsCoordinateReferenceSystem('EPSG:28356'), 2))
+        self.assertTrue(context.addDestinationDatumTransform(QgsCoordinateReferenceSystem('EPSG:3113'), 11))
+        self.assertTrue(context.addDestinationDatumTransform(QgsCoordinateReferenceSystem('EPSG:28355'), 12))
+        self.assertTrue(context.addSourceDestinationDatumTransform(QgsCoordinateReferenceSystem('EPSG:3111'),
+                                                                   QgsCoordinateReferenceSystem('EPSG:4283'), 1, 2))
+        self.assertTrue(context.addSourceDestinationDatumTransform(QgsCoordinateReferenceSystem('EPSG:28356'),
+                                                                   QgsCoordinateReferenceSystem(4283), 3, 4))
+
+        self.assertEqual(context.sourceDatumTransforms(), {'EPSG:3111': 1, 'EPSG:28356': 2})
+        self.assertEqual(context.destinationDatumTransforms(), {'EPSG:3113': 11, 'EPSG:28355': 12})
+        self.assertEqual(context.sourceDestinationDatumTransforms(), {('EPSG:3111', 'EPSG:4283'): (1, 2),
+                                                                      ('EPSG:28356', 'EPSG:4283'): (3, 4)})
+
+        # save to xml
+        doc = QDomDocument("testdoc")
+        elem = doc.createElement("test")
+        context.writeXml(elem, doc, QgsReadWriteContext())
+
+        # restore from xml
+        context2 = QgsCoordinateTransformContext()
+        context2.readXml(elem, doc, QgsReadWriteContext())
+
+        # check result
+        self.assertEqual(context2.sourceDatumTransforms(), {'EPSG:3111': 1, 'EPSG:28356': 2})
+        self.assertEqual(context2.destinationDatumTransforms(), {'EPSG:3113': 11, 'EPSG:28355': 12})
+        self.assertEqual(context2.sourceDestinationDatumTransforms(), {('EPSG:3111', 'EPSG:4283'): (1, 2),
+                                                                       ('EPSG:28356', 'EPSG:4283'): (3, 4)})
+
 
 if __name__ == '__main__':
     unittest.main()