Add methods to add/subtract QgsVectors

nyalldawson · nyalldawson · commit 77a8e18ec1ea · 2016-12-09T08:13:48.000+10:00
diff --git a/python/core/qgspoint.sip b/python/core/qgspoint.sip
@@ -39,6 +39,30 @@ class QgsVector
      */
     double operator*( QgsVector v ) const;
 
+    /**
+     * Adds another vector to this vector.
+     * @node added in QGIS 3.0
+     */
+    QgsVector operator+( QgsVector other ) const;
+
+    /**
+     * Adds another vector to this vector in place.
+     * @node added in QGIS 3.0
+     */
+    QgsVector& operator+=( QgsVector other );
+
+    /**
+     * Subtracts another vector to this vector.
+     * @node added in QGIS 3.0
+     */
+    QgsVector operator-( QgsVector other ) const;
+
+    /**
+     * Subtracts another vector to this vector in place.
+     * @node added in QGIS 3.0
+     */
+    QgsVector& operator-=( QgsVector other );
+
     /** Returns the length of the vector.
      */
     double length() const;
diff --git a/src/core/qgspoint.cpp b/src/core/qgspoint.cpp
@@ -60,6 +60,30 @@ double QgsVector::operator*( QgsVector v ) const
   return mX * v.mX + mY * v.mY;
 }
 
+QgsVector QgsVector::operator+( QgsVector other ) const
+{
+  return QgsVector( mX + other.mX, mY + other.mY );
+}
+
+QgsVector& QgsVector::operator+=( QgsVector other )
+{
+  mX += other.mX;
+  mY += other.mY;
+  return *this;
+}
+
+QgsVector QgsVector::operator-( QgsVector other ) const
+{
+  return QgsVector( mX - other.mX, mY - other.mY );
+}
+
+QgsVector& QgsVector::operator-=( QgsVector other )
+{
+  mX -= other.mX;
+  mY -= other.mY;
+  return *this;
+}
+
 double QgsVector::length() const
 {
   return sqrt( mX * mX + mY * mY );
diff --git a/src/core/qgspoint.h b/src/core/qgspoint.h
@@ -57,11 +57,36 @@ class CORE_EXPORT QgsVector
      */
     QgsVector operator/( double scalar ) const;
 
-    /** Returns the sum of the x component of this vector multiplied by the x component of another
-     * vector plus the y component of this vector multipled by the y component of another vector.
+    /** Returns the dot product of two vectors, which is the sum of the x component
+     *  of this vector multiplied by the x component of another
+     *  vector plus the y component of this vector multipled by the y component of another vector.
      */
     double operator*( QgsVector v ) const;
 
+    /**
+     * Adds another vector to this vector.
+     * @note added in QGIS 3.0
+     */
+    QgsVector operator+( QgsVector other ) const;
+
+    /**
+     * Adds another vector to this vector in place.
+     * @note added in QGIS 3.0
+     */
+    QgsVector& operator+=( QgsVector other );
+
+    /**
+     * Subtracts another vector to this vector.
+     * @note added in QGIS 3.0
+     */
+    QgsVector operator-( QgsVector other ) const;
+
+    /**
+     * Subtracts another vector to this vector in place.
+     * @note added in QGIS 3.0
+     */
+    QgsVector& operator-=( QgsVector other );
+
     /** Returns the length of the vector.
      */
     double length() const;
diff --git a/tests/src/core/testqgspoint.cpp b/tests/src/core/testqgspoint.cpp
@@ -736,6 +736,23 @@ void TestQgsPoint::vector()
   QCOMPARE( QgsVector( 0, 2 ).normalized().y(), 1.0 );
   QCOMPARE( QgsVector( 2, 0 ).normalized().x(), 1.0 );
   QCOMPARE( QgsVector( 2, 0 ).normalized().y(), 0.0 );
+
+  // operator +, -
+  v1 = QgsVector( 1, 3 );
+  v2 = QgsVector( 2, 5 );
+  QgsVector v3 = v1 + v2;
+  QCOMPARE( v3.x(), 3.0 );
+  QCOMPARE( v3.y(), 8.0 );
+  v3 = v1 - v2;
+  QCOMPARE( v3.x(), -1.0 );
+  QCOMPARE( v3.y(), -2.0 );
+  // operator +=, -=
+  v1 += v2;
+  QCOMPARE( v1.x(), 3.0 );
+  QCOMPARE( v1.y(), 8.0 );
+  v1 -= v2;
+  QCOMPARE( v1.x(), 1.0 );
+  QCOMPARE( v1.y(), 3.0 );
 }
 
 QTEST_MAIN( TestQgsPoint )
