Add rotate and transform(QTransform) methods to QgsGeometry

Reimplement translate in terms of transform(QTransform).
Includes new unit test for rotate() and translate() methods.
Includes sip bindings update.

Author: Sandro Santilli

python/core/qgsgeometry.sip

@@ -251,6 +251,18 @@ class QgsGeometry
      @return 0 in case of success*/
     int transform( const QgsCoordinateTransform& ct );
 
+    /**Transform this geometry as described by QTransform ct
+     @note added in 2.8
+     @return 0 in case of success*/
+    int transform( const QTransform& ct );
+
+    /**Rotate this geometry around the Z axis
+     @note added in 2.8
+     @param rotation clockwise rotation in degrees
+     @param center rotation center
+     @return 0 in case of success*/
+    int rotate( double rotation, const QgsPoint& center );
+
     /**Splits this geometry according to a given line. Note that the geometry is only split once. If there are several intersections
      between geometry and splitLine, only the first one is considered.
     @param splitLine the line that splits the geometry

src/core/qgsgeometry.cpp

@@ -2706,7 +2706,7 @@ int QgsGeometry::addPart( GEOSGeometry *newPart )
   return 0;
 }
 
-int QgsGeometry::translate( double dx, double dy )
+int QgsGeometry::transform( const QTransform& t )
 {
   if ( mDirtyWkb )
     exportGeosToWkb();
@@ -2717,17 +2717,17 @@ int QgsGeometry::translate( double dx, double dy )
     return 1;
   }
 
+  bool hasZValue = false;
   QgsWkbPtr wkbPtr( mGeometry + 1 );
   QGis::WkbType wkbType;
   wkbPtr >> wkbType;
 
-  bool hasZValue = false;
   switch ( wkbType )
   {
     case QGis::WKBPoint25D:
     case QGis::WKBPoint:
     {
-      translateVertex( wkbPtr, dx, dy, hasZValue );
+      transformVertex( wkbPtr, t, hasZValue );
     }
     break;
 
@@ -2738,7 +2738,7 @@ int QgsGeometry::translate( double dx, double dy )
       int nPoints;
       wkbPtr >> nPoints;
       for ( int index = 0; index < nPoints; ++index )
-        translateVertex( wkbPtr, dx, dy, hasZValue );
+        transformVertex( wkbPtr, t, hasZValue );
 
       break;
     }
@@ -2754,7 +2754,7 @@ int QgsGeometry::translate( double dx, double dy )
         int nPoints;
         wkbPtr >> nPoints;
         for ( int index2 = 0; index2 < nPoints; ++index2 )
-          translateVertex( wkbPtr, dx, dy, hasZValue );
+          transformVertex( wkbPtr, t, hasZValue );
 
       }
       break;
@@ -2766,11 +2766,10 @@ int QgsGeometry::translate( double dx, double dy )
     {
       int nPoints;
       wkbPtr >> nPoints;
-
       for ( int index = 0; index < nPoints; ++index )
       {
         wkbPtr += 1 + sizeof( int );
-        translateVertex( wkbPtr, dx, dy, hasZValue );
+        transformVertex( wkbPtr, t, hasZValue );
       }
       break;
     }
@@ -2787,7 +2786,8 @@ int QgsGeometry::translate( double dx, double dy )
         int nPoints;
         wkbPtr >> nPoints;
         for ( int index2 = 0; index2 < nPoints; ++index2 )
-          translateVertex( wkbPtr, dx, dy, hasZValue );
+          transformVertex( wkbPtr, t, hasZValue );
+
       }
       break;
     }
@@ -2801,19 +2801,17 @@ int QgsGeometry::translate( double dx, double dy )
       for ( int index = 0; index < nPolys; ++index )
       {
         wkbPtr += 1 + sizeof( int ); //skip endian and polygon type
-
         int nRings;
         wkbPtr >> nRings;
-
         for ( int index2 = 0; index2 < nRings; ++index2 )
         {
           int nPoints;
           wkbPtr >> nPoints;
           for ( int index3 = 0; index3 < nPoints; ++index3 )
-            translateVertex( wkbPtr, dx, dy, hasZValue );
+            transformVertex( wkbPtr, t, hasZValue );
+
         }
       }
-      break;
     }
 
     default:
@@ -2823,6 +2821,19 @@ int QgsGeometry::translate( double dx, double dy )
   return 0;
 }
 
+int QgsGeometry::translate( double dx, double dy )
+{
+  return transform( QTransform::fromTranslate( dx, dy ) );
+}
+
+int QgsGeometry::rotate( double rotation, const QgsPoint& center )
+{
+  QTransform t = QTransform::fromTranslate( center.x(), center.y() );
+  t.rotate( -rotation );
+  t.translate( -center.x(), -center.y() );
+  return transform( t );
+}
+
 int QgsGeometry::transform( const QgsCoordinateTransform& ct )
 {
   if ( mDirtyWkb )
@@ -4612,20 +4623,25 @@ bool QgsGeometry::convertToMultiType()
   return true;
 }
 
-void QgsGeometry::translateVertex( QgsWkbPtr &wkbPtr, double dx, double dy, bool hasZValue )
+void QgsGeometry::transformVertex( QgsWkbPtr &wkbPtr, const QTransform& trans, bool hasZValue )
 {
-  double x, y, translated_x, translated_y;
+  double x, y, rotated_x, rotated_y;
+
+  QgsWkbPtr tmp = wkbPtr;
+
+  memcpy( &x, tmp, sizeof( double ) );
+  tmp += sizeof( double );
+  memcpy( &y, tmp, sizeof( double ) );
+  tmp += sizeof( double );
+
+  trans.map( x, y, &rotated_x, &rotated_y );
 
   //x-coordinate
-  memcpy( &x, wkbPtr, sizeof( double ) );
-  translated_x = x + dx;
-  memcpy( wkbPtr, &translated_x, sizeof( double ) );
+  memcpy( wkbPtr, &rotated_x, sizeof( double ) );
   wkbPtr += sizeof( double );
 
   //y-coordinate
-  memcpy( &y, wkbPtr, sizeof( double ) );
-  translated_y = y + dy;
-  memcpy( wkbPtr, &translated_y, sizeof( double ) );
+  memcpy( wkbPtr, &rotated_y, sizeof( double ) );
   wkbPtr += sizeof( double );
 
   if ( hasZValue )

src/core/qgsgeometry.h

@@ -293,6 +293,18 @@ class CORE_EXPORT QgsGeometry
      @return 0 in case of success*/
     int transform( const QgsCoordinateTransform& ct );
 
+    /**Transform this geometry as described by QTransform ct
+     @note added in 2.8
+     @return 0 in case of success*/
+    int transform( const QTransform& ct );
+
+    /**Rotate this geometry around the Z axis
+     @note added in 2.8
+     @param rotation clockwise rotation in degrees
+     @param center rotation center
+     @return 0 in case of success*/
+    int rotate( double rotation, const QgsPoint& center );
+
     /**Splits this geometry according to a given line. Note that the geometry is only split once. If there are several intersections
      between geometry and splitLine, only the first one is considered.
     @param splitLine the line that splits the geometry
@@ -565,12 +577,11 @@ class CORE_EXPORT QgsGeometry
                        const GEOSCoordSequence*  old_sequence,
                        GEOSCoordSequence** new_sequence );
 
-    /**Translates a single vertex by dx and dy.
+    /**Transform a single vertex by QTransform
     @param wkbPtr pointer to current position in wkb array. Is increased automatically by the function
-    @param dx translation of x coordinate
-    @param dy translation of y coordinate
+    @param trans transform matrix
     @param hasZValue 25D type?*/
-    void translateVertex( QgsWkbPtr &wkbPtr, double dx, double dy, bool hasZValue );
+    void transformVertex( QgsWkbPtr &wkbPtr, const QTransform& trans, bool hasZValue );
 
     /**Transforms a single vertex by ct.
     @param wkbPtr pointer to current position in wkb. Is increased automatically by the function

tests/src/core/testqgsgeometry.cpp

@@ -60,6 +60,8 @@ class TestQgsGeometry : public QObject
 #endif
     void intersectionCheck1();
     void intersectionCheck2();
+    void translateCheck1();
+    void rotateCheck1();
     void unionCheck1();
     void unionCheck2();
     void differenceCheck1();
@@ -359,6 +361,81 @@ void TestQgsGeometry::intersectionCheck2()
   QVERIFY( !mpPolygonGeometryA->intersects( mpPolygonGeometryC ) );
 }
 
+void TestQgsGeometry::translateCheck1()
+{
+  QString wkt = "LINESTRING(0 0, 10 0, 10 10)";
+  QScopedPointer<QgsGeometry> geom( QgsGeometry::fromWkt( wkt ) );
+  geom->translate( 10, -5 );
+  QString obtained = geom->exportToWkt();
+  QString expected = "LINESTRING(10 -5, 20 -5, 20 5)";
+  QCOMPARE( obtained, expected );
+  geom->translate( -10, 5 );
+  obtained = geom->exportToWkt();
+  QCOMPARE( obtained, wkt );
+
+  wkt = "POLYGON((-2 4,-2 -10,2 3,-2 4),(1 1,-1 1,-1 -1,1 1))";
+  geom.reset( QgsGeometry::fromWkt( wkt ) );
+  geom->translate( -2, 10 );
+  obtained = geom->exportToWkt();
+  expected = "POLYGON((-4 14,-4 0,0 13,-4 14),(-1 11,-3 11,-3 9,-1 11))";
+  QCOMPARE( obtained, expected );
+  geom->translate( 2, -10 );
+  obtained = geom->exportToWkt();
+  QCOMPARE( obtained, wkt );
+
+  wkt = "POINT(40 50)";
+  geom.reset( QgsGeometry::fromWkt( wkt ) );
+  geom->translate( -2, 10 );
+  obtained = geom->exportToWkt();
+  expected = "POINT(38 60)";
+  QCOMPARE( obtained, expected );
+  geom->translate( 2, -10 );
+  obtained = geom->exportToWkt();
+  QCOMPARE( obtained, wkt );
+
+}
+
+void TestQgsGeometry::rotateCheck1()
+{
+  QString wkt = "LINESTRING(0 0, 10 0, 10 10)";
+  QScopedPointer<QgsGeometry> geom( QgsGeometry::fromWkt( wkt ) );
+  geom->rotate( 90, QgsPoint( 0, 0 ) );
+  QString obtained = geom->exportToWkt();
+  QString expected = "LINESTRING(0 0, 0 -10, 10 -10)";
+  QCOMPARE( obtained, expected );
+  geom->rotate( -90, QgsPoint( 0, 0 ) );
+  obtained = geom->exportToWkt();
+  QCOMPARE( obtained, wkt );
+
+  wkt = "POLYGON((-2 4,-2 -10,2 3,-2 4),(1 1,-1 1,-1 -1,1 1))";
+  geom.reset( QgsGeometry::fromWkt( wkt ) );
+  geom->rotate( 90, QgsPoint( 0, 0 ) );
+  obtained = geom->exportToWkt();
+  expected = "POLYGON((4 2,-10 2,3 -2,4 2),(1 -1,1 1,-1 1,1 -1))";
+  QCOMPARE( obtained, expected );
+  geom->rotate( -90, QgsPoint( 0, 0 ) );
+  obtained = geom->exportToWkt();
+  QCOMPARE( obtained, wkt );
+
+  wkt = "POINT(40 50)";
+  geom.reset( QgsGeometry::fromWkt( wkt ) );
+  geom->rotate( 90, QgsPoint( 0, 0 ) );
+  obtained = geom->exportToWkt();
+  expected = "POINT(50 -40)";
+  QCOMPARE( obtained, expected );
+  geom->rotate( -90, QgsPoint( 0, 0 ) );
+  obtained = geom->exportToWkt();
+  QCOMPARE( obtained, wkt );
+  geom->rotate( 180, QgsPoint( 40, 0 ) );
+  expected = "POINT(40 -50)";
+  obtained = geom->exportToWkt();
+  QCOMPARE( obtained, expected );
+  geom->rotate( 180, QgsPoint( 40, 0 ) ); // round-trip
+  obtained = geom->exportToWkt();
+  QCOMPARE( obtained, wkt );
+
+}
+
 void TestQgsGeometry::unionCheck1()
 {
   // should be a multipolygon with 2 parts as A does not intersect C