Add center() function to QGeoShape.

It is frequently useful to calculate the geometric center of a shape.
Both QGeoCircle and QGeoRectangle already define center() functions,
however, the application developer must cast each QGeoShape into either
a QGeoCirlce or QGeoRectangle before calling. Providing
QGeoShape::center() allows application code to be simplified.

Existing QGeoCircle::center() and QGeoRectangle::center() functions are
kept for compatibility.

Change-Id: I92b727ab5e713f70174588a27040446c992ae14e
Reviewed-by: Alex Blasche <alexander.blasche@theqtcompany.com>

7 files changed, 62 insertions, 30 deletions

diff --git a/src/positioning/qgeocircle.cpp b/src/positioning/qgeocircle.cpp
index 459ce824..61336d1f 100644
--- a/src/positioning/qgeocircle.cpp
+++ b/src/positioning/qgeocircle.cpp
@@ -151,7 +151,7 @@ bool QGeoCircle::operator!=(const QGeoCircle &other) const
 
 bool QGeoCirclePrivate::isValid() const
 {
-    return center.isValid() && !qIsNaN(radius) && radius >= -1e-7;
+    return m_center.isValid() && !qIsNaN(radius) && radius >= -1e-7;
 }
 
 bool QGeoCirclePrivate::isEmpty() const
@@ -166,17 +166,17 @@ void QGeoCircle::setCenter(const QGeoCoordinate &center)
 {
     Q_D(QGeoCircle);
 
-    d->center = center;
+    d->m_center = center;
 }
 
 /*!
-    Returns the center coordinate of this geo circle.
+    Returns the center coordinate of this geo circle. Equivalent to QGeoShape::center().
 */
 QGeoCoordinate QGeoCircle::center() const
 {
     Q_D(const QGeoCircle);
 
-    return d->center;
+    return d->center();
 }
 
 /*!
@@ -205,13 +205,18 @@ bool QGeoCirclePrivate::contains(const QGeoCoordinate &coordinate) const
         return false;
 
     // see QTBUG-41447 for details
-    qreal distance = center.distanceTo(coordinate);
+    qreal distance = m_center.distanceTo(coordinate);
     if (qFuzzyCompare(distance, radius) || distance <= radius)
         return true;
 
     return false;
 }
 
+QGeoCoordinate QGeoCirclePrivate::center() const
+{
+    return m_center;
+}
+
 /*!
   Extends the circle to include \a coordinate
 */
@@ -220,7 +225,7 @@ void QGeoCirclePrivate::extendShape(const QGeoCoordinate &coordinate)
     if (!isValid() || !coordinate.isValid() || contains(coordinate))
         return;
 
-    radius = center.distanceTo(coordinate);
+    radius = m_center.distanceTo(coordinate);
 }
 
 /*!
@@ -235,8 +240,8 @@ void QGeoCircle::translate(double degreesLatitude, double degreesLongitude)
 
     Q_D(QGeoCircle);
 
-    double lat = d->center.latitude();
-    double lon = d->center.longitude();
+    double lat = d->m_center.latitude();
+    double lon = d->m_center.longitude();
 
     lat += degreesLatitude;
     lon += degreesLongitude;
@@ -262,7 +267,7 @@ void QGeoCircle::translate(double degreesLatitude, double degreesLongitude)
             lon -= 180;
     }
 
-    d->center = QGeoCoordinate(lat, lon);
+    d->m_center = QGeoCoordinate(lat, lon);
 }
 
 /*!
@@ -290,12 +295,12 @@ QGeoCirclePrivate::QGeoCirclePrivate()
 }
 
 QGeoCirclePrivate::QGeoCirclePrivate(const QGeoCoordinate &center, qreal radius)
-:   QGeoShapePrivate(QGeoShape::CircleType), center(center), radius(radius)
+:   QGeoShapePrivate(QGeoShape::CircleType), m_center(center), radius(radius)
 {
 }
 
 QGeoCirclePrivate::QGeoCirclePrivate(const QGeoCirclePrivate &other)
-:   QGeoShapePrivate(QGeoShape::CircleType), center(other.center),
+:   QGeoShapePrivate(QGeoShape::CircleType), m_center(other.m_center),
     radius(other.radius)
 {
 }
@@ -314,7 +319,7 @@ bool QGeoCirclePrivate::operator==(const QGeoShapePrivate &other) const
 
     const QGeoCirclePrivate &otherCircle = static_cast<const QGeoCirclePrivate &>(other);
 
-    return radius == otherCircle.radius && center == otherCircle.center;
+    return radius == otherCircle.radius && m_center == otherCircle.m_center;
 }
 
 QT_END_NAMESPACE
diff --git a/src/positioning/qgeocircle_p.h b/src/positioning/qgeocircle_p.h
index d6fe37b5..635bd2ec 100644
--- a/src/positioning/qgeocircle_p.h
+++ b/src/positioning/qgeocircle_p.h
@@ -62,13 +62,15 @@ public:
     bool isEmpty() const;
     bool contains(const QGeoCoordinate &coordinate) const;
 
+    QGeoCoordinate center() const Q_DECL_OVERRIDE;
+
     void extendShape(const QGeoCoordinate &coordinate);
 
     QGeoShapePrivate *clone() const;
 
     bool operator==(const QGeoShapePrivate &other) const;
 
-    QGeoCoordinate center;
+    QGeoCoordinate m_center;
     qreal radius;
 };
 
diff --git a/src/positioning/qgeorectangle.cpp b/src/positioning/qgeorectangle.cpp
index d514edf9..808e091c 100644
--- a/src/positioning/qgeorectangle.cpp
+++ b/src/positioning/qgeorectangle.cpp
@@ -374,28 +374,13 @@ void QGeoRectangle::setCenter(const QGeoCoordinate &center)
 }
 
 /*!
-    Returns the center of this geo rectangle.
+    Returns the center of this geo rectangle. Equivalent to QGeoShape::center().
 */
 QGeoCoordinate QGeoRectangle::center() const
 {
-    if (!isValid())
-        return QGeoCoordinate();
-
     Q_D(const QGeoRectangle);
 
-    double cLat = (d->topLeft.latitude() + d->bottomRight.latitude()) / 2.0;
-
-    double cLon = (d->bottomRight.longitude() + d->topLeft.longitude()) / 2.0;
-    if (d->topLeft.longitude() > d->bottomRight.longitude()) {
-        cLon = cLon - 180.0;
-    }
-
-    if (cLon < -180.0)
-        cLon += 360.0;
-    if (cLon > 180.0)
-        cLon -= 360.0;
-
-    return QGeoCoordinate(cLat, cLon);
+    return d->center();
 }
 
 /*!
@@ -586,6 +571,25 @@ bool QGeoRectanglePrivate::contains(const QGeoCoordinate &coordinate) const
     return true;
 }
 
+QGeoCoordinate QGeoRectanglePrivate::center() const
+{
+    if (!isValid())
+        return QGeoCoordinate();
+
+    double cLat = (topLeft.latitude() + bottomRight.latitude()) / 2.0;
+    double cLon = (bottomRight.longitude() + topLeft.longitude()) / 2.0;
+
+    if (topLeft.longitude() > bottomRight.longitude())
+        cLon = cLon - 180.0;
+
+    if (cLon < -180.0)
+        cLon += 360.0;
+    if (cLon > 180.0)
+        cLon -= 360.0;
+
+    return QGeoCoordinate(cLat, cLon);
+}
+
 /*!
     Returns whether the geo rectangle \a rectangle is contained within this
     geo rectangle.
diff --git a/src/positioning/qgeorectangle_p.h b/src/positioning/qgeorectangle_p.h
index 1c5bc6f2..817fd360 100644
--- a/src/positioning/qgeorectangle_p.h
+++ b/src/positioning/qgeorectangle_p.h
@@ -62,6 +62,8 @@ public:
     bool isEmpty() const;
     bool contains(const QGeoCoordinate &coordinate) const;
 
+    QGeoCoordinate center() const Q_DECL_OVERRIDE;
+
     void extendShape(const QGeoCoordinate &coordinate);
 
     QGeoShapePrivate *clone() const;
diff --git a/src/positioning/qgeoshape.cpp b/src/positioning/qgeoshape.cpp
index 932f7618..c331ef81 100644
--- a/src/positioning/qgeoshape.cpp
+++ b/src/positioning/qgeoshape.cpp
@@ -185,6 +185,21 @@ bool QGeoShape::contains(const QGeoCoordinate &coordinate) const
 }
 
 /*!
+    Returns the coordinate located at the geometric center of the geo shape.
+
+    \since 5.5
+*/
+QGeoCoordinate QGeoShape::center() const
+{
+    Q_D(const QGeoShape);
+
+    if (d)
+        return d->center();
+    else
+        return QGeoCoordinate();
+}
+
+/*!
     Extends the geo shape to also cover the coordinate \a coordinate
 */
 void QGeoShape::extendShape(const QGeoCoordinate &coordinate)
diff --git a/src/positioning/qgeoshape.h b/src/positioning/qgeoshape.h
index 3704ba6a..edaf263f 100644
--- a/src/positioning/qgeoshape.h
+++ b/src/positioning/qgeoshape.h
@@ -61,6 +61,8 @@ public:
     bool isEmpty() const;
     bool contains(const QGeoCoordinate &coordinate) const;
 
+    QGeoCoordinate center() const;
+
     void extendShape(const QGeoCoordinate &coordinate);
 
     bool operator==(const QGeoShape &other) const;
diff --git a/src/positioning/qgeoshape_p.h b/src/positioning/qgeoshape_p.h
index 62ddd77c..154a4505 100644
--- a/src/positioning/qgeoshape_p.h
+++ b/src/positioning/qgeoshape_p.h
@@ -61,6 +61,8 @@ public:
     virtual bool isEmpty() const = 0;
     virtual bool contains(const QGeoCoordinate &coordinate) const = 0;
 
+    virtual QGeoCoordinate center() const = 0;
+
     virtual void extendShape(const QGeoCoordinate &coordinate) = 0;
 
     virtual QGeoShapePrivate *clone() const = 0;