Add convenience constructor to create QgsLineString between two points

qgis · Apr 23, 2018 · 3f3b951 · 3f3b951
1 parent fbf6b4a
commit 3f3b951
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diff --git a/python/core/geometry/qgslinestring.sip.in b/python/core/geometry/qgslinestring.sip.in
@@ -46,6 +46,13 @@ This constructor is more efficient then calling setPoints()
 or repeatedly calling addVertex()
 
 .. versionadded:: 3.0
+%End
+
+    QgsLineString( const QgsPoint &p1, const QgsPoint &p2 );
+%Docstring
+Constructs a linestring with a single segment from ``p1`` to ``p2``.
+
+.. versionadded:: 3.2
 %End
 
     QgsLineString( const QVector<QgsPointXY> &points );

diff --git a/src/core/geometry/qgslinestring.cpp b/src/core/geometry/qgslinestring.cpp
@@ -124,6 +124,31 @@ QgsLineString::QgsLineString( const QVector<double> &x, const QVector<double> &y
   }
 }
 
+QgsLineString::QgsLineString( const QgsPoint &p1, const QgsPoint &p2 )
+{
+  mWkbType = QgsWkbTypes::LineString;
+  mX.resize( 2 );
+  mX[ 0 ] = p1.x();
+  mX[ 1 ] = p2.x();
+  mY.resize( 2 );
+  mY[ 0 ] = p1.y();
+  mY[ 1 ] = p2.y();
+  if ( p1.is3D() )
+  {
+    mWkbType = QgsWkbTypes::addZ( mWkbType );
+    mZ.resize( 2 );
+    mZ[ 0 ] = p1.z();
+    mZ[ 1 ] = p2.z();
+  }
+  if ( p1.isMeasure() )
+  {
+    mWkbType = QgsWkbTypes::addM( mWkbType );
+    mM.resize( 2 );
+    mM[ 0 ] = p1.m();
+    mM[ 1 ] = p2.m();
+  }
+}
+
 QgsLineString::QgsLineString( const QVector<QgsPointXY> &points )
 {
   mWkbType = QgsWkbTypes::LineString;

diff --git a/src/core/geometry/qgslinestring.h b/src/core/geometry/qgslinestring.h
@@ -63,6 +63,12 @@ class CORE_EXPORT QgsLineString: public QgsCurve
                    const QVector<double> &z = QVector<double>(),
                    const QVector<double> &m = QVector<double>() );
 
+    /**
+     * Constructs a linestring with a single segment from \a p1 to \a p2.
+     * \since QGIS 3.2
+     */
+    QgsLineString( const QgsPoint &p1, const QgsPoint &p2 );
+
     /**
      * Construct a linestring from list of points.
      * This constructor is more efficient then calling setPoints()

diff --git a/tests/src/core/testqgsgeometry.cpp b/tests/src/core/testqgsgeometry.cpp
@@ -2696,6 +2696,44 @@ void TestQgsGeometry::lineString()
   QCOMPARE( fromVector3D.yAt( 1 ), 40.0 );
   QCOMPARE( fromVector3D.zAt( 1 ), 200.0 );
 
+  // from 2 points
+  QgsLineString from2Pts( QgsPoint( 1, 2 ), QgsPoint( 21, 22 ) );
+  QCOMPARE( from2Pts.wkbType(), QgsWkbTypes::LineString );
+  QCOMPARE( from2Pts.numPoints(), 2 );
+  QCOMPARE( from2Pts.xAt( 0 ), 1.0 );
+  QCOMPARE( from2Pts.yAt( 0 ), 2.0 );
+  QCOMPARE( from2Pts.xAt( 1 ), 21.0 );
+  QCOMPARE( from2Pts.yAt( 1 ), 22.0 );
+  from2Pts = QgsLineString( QgsPoint( QgsWkbTypes::PointZ, 1, 2, 3 ), QgsPoint( QgsWkbTypes::PointZ, 21, 22, 23 ) );
+  QCOMPARE( from2Pts.wkbType(), QgsWkbTypes::LineStringZ );
+  QCOMPARE( from2Pts.numPoints(), 2 );
+  QCOMPARE( from2Pts.xAt( 0 ), 1.0 );
+  QCOMPARE( from2Pts.yAt( 0 ), 2.0 );
+  QCOMPARE( from2Pts.zAt( 0 ), 3.0 );
+  QCOMPARE( from2Pts.xAt( 1 ), 21.0 );
+  QCOMPARE( from2Pts.yAt( 1 ), 22.0 );
+  QCOMPARE( from2Pts.zAt( 1 ), 23.0 );
+  from2Pts = QgsLineString( QgsPoint( QgsWkbTypes::PointM, 1, 2, 0, 3 ), QgsPoint( QgsWkbTypes::PointM, 21, 22, 0, 23 ) );
+  QCOMPARE( from2Pts.wkbType(), QgsWkbTypes::LineStringM );
+  QCOMPARE( from2Pts.numPoints(), 2 );
+  QCOMPARE( from2Pts.xAt( 0 ), 1.0 );
+  QCOMPARE( from2Pts.yAt( 0 ), 2.0 );
+  QCOMPARE( from2Pts.mAt( 0 ), 3.0 );
+  QCOMPARE( from2Pts.xAt( 1 ), 21.0 );
+  QCOMPARE( from2Pts.yAt( 1 ), 22.0 );
+  QCOMPARE( from2Pts.mAt( 1 ), 23.0 );
+  from2Pts = QgsLineString( QgsPoint( QgsWkbTypes::PointZM, 1, 2, 3, 4 ), QgsPoint( QgsWkbTypes::PointZM, 21, 22, 23, 24 ) );
+  QCOMPARE( from2Pts.wkbType(), QgsWkbTypes::LineStringZM );
+  QCOMPARE( from2Pts.numPoints(), 2 );
+  QCOMPARE( from2Pts.xAt( 0 ), 1.0 );
+  QCOMPARE( from2Pts.yAt( 0 ), 2.0 );
+  QCOMPARE( from2Pts.zAt( 0 ), 3.0 );
+  QCOMPARE( from2Pts.mAt( 0 ), 4.0 );
+  QCOMPARE( from2Pts.xAt( 1 ), 21.0 );
+  QCOMPARE( from2Pts.yAt( 1 ), 22.0 );
+  QCOMPARE( from2Pts.zAt( 1 ), 23.0 );
+  QCOMPARE( from2Pts.mAt( 1 ), 24.0 );
+
   //addVertex
   QgsLineString l2;
   l2.addVertex( QgsPoint( 1.0, 2.0 ) );