From a7372fd79d9416d4b0de3d47ef869aff12048aa3 Mon Sep 17 00:00:00 2001
From: Lorenz Haas <lorenz.haas@histomatics.de>
Date: Sun, 1 May 2016 22:47:01 +0200
Subject: Add QLineF::center() returning the point in the center of the line

[ChangeLog][QtCore][QLine/QLineF] Added center().

Change-Id: I6dcfa9e839190c0a4caf36fb6ecd01b37d65d274
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
---
 src/corelib/tools/qline.cpp | 23 +++++++++++++++++++++++
 src/corelib/tools/qline.h   | 14 ++++++++++++++
 2 files changed, 37 insertions(+)

(limited to 'src/corelib')

diff --git a/src/corelib/tools/qline.cpp b/src/corelib/tools/qline.cpp
index b004f74be9..8942292a3d 100644
--- a/src/corelib/tools/qline.cpp
+++ b/src/corelib/tools/qline.cpp
@@ -214,6 +214,14 @@ QT_BEGIN_NAMESPACE
     Returns this line translated the distance specified by \a dx and \a dy.
 */
 
+/*!
+    \fn QPoint QLine::center() const
+
+    \since 5.8
+
+    Returns the center point of this line. This is equivalent to
+    (p1() + p2()) / 2, except it will never overflow.
+*/
 
 /*!
     \fn void QLine::setP1(const QPoint &p1)
@@ -351,6 +359,12 @@ QDataStream &operator>>(QDataStream &stream, QLine &line)
     translate() function, and can be traversed using the pointAt()
     function.
 
+    \section1 Constraints
+
+    QLine is limited to the minimum and maximum values for the
+    \c int type. Operations on a QLine that could potentially result
+    in values outside this range will result in undefined behavior.
+
     \sa QLine, QPolygonF, QRectF
 */
 
@@ -710,6 +724,15 @@ QLineF::IntersectType QLineF::intersect(const QLineF &l, QPointF *intersectionPo
     Returns this line translated the distance specified by \a dx and \a dy.
 */
 
+/*!
+    \fn QPointF QLineF::center() const
+
+    \since 5.8
+
+    Returns the center point of this line. This is equivalent to
+    0.5 * p1() + 0.5 * p2().
+*/
+
 /*!
     \fn void QLineF::setP1(const QPointF &p1)
     \since 4.4
diff --git a/src/corelib/tools/qline.h b/src/corelib/tools/qline.h
index 819dd3fd3b..5b5ca3b4c8 100644
--- a/src/corelib/tools/qline.h
+++ b/src/corelib/tools/qline.h
@@ -76,6 +76,8 @@ public:
     Q_DECL_CONSTEXPR inline QLine translated(const QPoint &p) const Q_REQUIRED_RESULT;
     Q_DECL_CONSTEXPR inline QLine translated(int dx, int dy) const Q_REQUIRED_RESULT;
 
+    Q_DECL_CONSTEXPR inline QPoint center() const Q_REQUIRED_RESULT;
+
     inline void setP1(const QPoint &p1);
     inline void setP2(const QPoint &p2);
     inline void setPoints(const QPoint &p1, const QPoint &p2);
@@ -165,6 +167,11 @@ Q_DECL_CONSTEXPR inline QLine QLine::translated(int adx, int ady) const
     return translated(QPoint(adx, ady));
 }
 
+Q_DECL_CONSTEXPR inline QPoint QLine::center() const
+{
+    return QPoint(int((qint64(pt1.x()) + pt2.x()) / 2), int((qint64(pt1.y()) + pt2.y()) / 2));
+}
+
 inline void QLine::setP1(const QPoint &aP1)
 {
     pt1 = aP1;
@@ -253,6 +260,8 @@ public:
     Q_DECL_CONSTEXPR inline QLineF translated(const QPointF &p) const Q_REQUIRED_RESULT;
     Q_DECL_CONSTEXPR inline QLineF translated(qreal dx, qreal dy) const Q_REQUIRED_RESULT;
 
+    Q_DECL_CONSTEXPR inline QPointF center() const Q_REQUIRED_RESULT;
+
     inline void setP1(const QPointF &p1);
     inline void setP2(const QPointF &p2);
     inline void setPoints(const QPointF &p1, const QPointF &p2);
@@ -357,6 +366,11 @@ Q_DECL_CONSTEXPR inline QLineF QLineF::translated(qreal adx, qreal ady) const
     return translated(QPointF(adx, ady));
 }
 
+Q_DECL_CONSTEXPR inline QPointF QLineF::center() const
+{
+    return QPointF(0.5 * pt1.x() + 0.5 * pt2.x(), 0.5 * pt1.y() + 0.5 * pt2.y());
+}
+
 inline void QLineF::setLength(qreal len)
 {
     if (isNull())
-- 
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