Normalize rounding

Change the rounding of negative half values to match standard C++
round, this will also allow future optimizations.

Change-Id: I8f8c71bed1f05891e82ea787c6bc284297de9c5c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

4 files changed, 10 insertions, 9 deletions

diff --git a/src/corelib/global/qglobal.cpp b/src/corelib/global/qglobal.cpp
index 39f36bb3cc..1c55cb8f9f 100644
--- a/src/corelib/global/qglobal.cpp
+++ b/src/corelib/global/qglobal.cpp
@@ -973,7 +973,7 @@ static_assert((std::is_same<qsizetype, qptrdiff>::value));
 
     Rounds \a d to the nearest integer.
 
-    Rounds half up (e.g. 0.5 -> 1, -0.5 -> 0).
+    Rounds half away from zero (e.g. 0.5 -> 1, -0.5 -> -1).
 
     Example:
 
@@ -985,7 +985,7 @@ static_assert((std::is_same<qsizetype, qptrdiff>::value));
 
     Rounds \a d to the nearest integer.
 
-    Rounds half up (e.g. 0.5f -> 1, -0.5f -> 0).
+    Rounds half away from zero (e.g. 0.5f -> 1, -0.5f -> -1).
 
     Example:
 
@@ -997,7 +997,7 @@ static_assert((std::is_same<qsizetype, qptrdiff>::value));
 
     Rounds \a d to the nearest 64-bit integer.
 
-    Rounds half up (e.g. 0.5 -> 1, -0.5 -> 0).
+    Rounds half away from zero (e.g. 0.5 -> 1, -0.5 -> -1).
 
     Example:
 
@@ -1009,7 +1009,7 @@ static_assert((std::is_same<qsizetype, qptrdiff>::value));
 
     Rounds \a d to the nearest 64-bit integer.
 
-    Rounds half up (e.g. 0.5f -> 1, -0.5f -> 0).
+    Rounds half away from zero (e.g. 0.5f -> 1, -0.5f -> -1).
 
     Example:
 
diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index 418cc2f66b..c268d59e8f 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -582,14 +582,14 @@ template <typename T>
 constexpr inline T qAbs(const T &t) { return t >= 0 ? t : -t; }
 
 constexpr inline int qRound(double d)
-{ return d >= 0.0 ? int(d + 0.5) : int(d - double(int(d-1)) + 0.5) + int(d-1); }
+{ return d >= 0.0 ? int(d + 0.5) : int(d - 0.5); }
 constexpr inline int qRound(float d)
-{ return d >= 0.0f ? int(d + 0.5f) : int(d - float(int(d-1)) + 0.5f) + int(d-1); }
+{ return d >= 0.0f ? int(d + 0.5f) : int(d - 0.5f); }
 
 constexpr inline qint64 qRound64(double d)
-{ return d >= 0.0 ? qint64(d + 0.5) : qint64(d - double(qint64(d-1)) + 0.5) + qint64(d-1); }
+{ return d >= 0.0 ? qint64(d + 0.5) : qint64(d - 0.5); }
 constexpr inline qint64 qRound64(float d)
-{ return d >= 0.0f ? qint64(d + 0.5f) : qint64(d - float(qint64(d-1)) + 0.5f) + qint64(d-1); }
+{ return d >= 0.0f ? qint64(d + 0.5f) : qint64(d - 0.5f); }
 
 namespace QTypeTraits {
 
diff --git a/tests/auto/corelib/tools/qpointf/tst_qpointf.cpp b/tests/auto/corelib/tools/qpointf/tst_qpointf.cpp
index e78a8e3082..ef08352dfc 100644
--- a/tests/auto/corelib/tools/qpointf/tst_qpointf.cpp
+++ b/tests/auto/corelib/tools/qpointf/tst_qpointf.cpp
@@ -381,7 +381,7 @@ void tst_QPointF::toPoint_data()
 
     QTest::newRow("(0.0, 0.0) ==> (0, 0)") << QPointF(0, 0) << QPoint(0, 0);
     QTest::newRow("(0.5, 0.5) ==> (1, 1)") << QPointF(0.5, 0.5) << QPoint(1, 1);
-    QTest::newRow("(-0.5, -0.5) ==> (0, 0)") << QPointF(-0.5, -0.5) << QPoint(0, 0);
+    QTest::newRow("(-0.5, -0.5) ==> (-1, -1)") << QPointF(-0.5, -0.5) << QPoint(-1, -1);
 }
 
 void tst_QPointF::toPoint()
diff --git a/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp b/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp
index 77b2c0251d..42a16dc1f4 100644
--- a/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp
+++ b/tests/auto/widgets/graphicsview/qgraphicsview/tst_qgraphicsview.cpp
@@ -4840,6 +4840,7 @@ public:
     {
         setFlag(QGraphicsItem::ItemIsFocusable, true);
         setFlag(QGraphicsItem::ItemAcceptsInputMethod, true);
+        setPen(Qt::NoPen); // Avoid adding a half pixel border to the rect.
     }
 
     QVariant inputMethodQuery(Qt::InputMethodQuery) const override