Provide operators for QMargins.

Provide addition/subtraction for QMargins as well as
multiplication and division for int/qreal similar
to QPoint. Add unary minus.

Change-Id: If4eb831cfd610b34b5ca361619b1636031811d0a
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>

2 files changed, 267 insertions, 0 deletions

diff --git a/src/corelib/tools/qmargins.cpp b/src/corelib/tools/qmargins.cpp
index 214466194a..e30675dc63 100644
--- a/src/corelib/tools/qmargins.cpp
+++ b/src/corelib/tools/qmargins.cpp
@@ -216,6 +216,181 @@ QT_BEGIN_NAMESPACE
     \since 5.1
 */
 
+/*!
+    \fn const QMargins operator+(const QMargins &m1, const QMargins &m2)
+    \relates QMargins
+
+    Returns a QMargins object that is the sum of the given margins, \a m1
+    and \a m2; each component is added separately.
+
+    \sa QMargins::operator+=(), QMargins::operator-=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn const QMargins operator-(const QMargins &m1, const QMargins &m2)
+    \relates QMargins
+
+    Returns a QMargins object that is formed by subtracting \a m2 from
+    \a m1; each component is subtracted separately.
+
+    \sa QMargins::operator+=(), QMargins::operator-=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn const QMargins operator*(const QMargins &margins, int factor)
+    \relates QMargins
+
+    Returns a QMargins object that is formed by multiplying each component
+    of the given \a margins by \a factor.
+
+    \sa QMargins::operator*=(), QMargins::operator/=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn const QMargins operator*(int factor, const QMargins &margins)
+    \relates QMargins
+    \overload
+
+    Returns a QMargins object that is formed by multiplying each component
+    of the given \a margins by \a factor.
+
+    \sa QMargins::operator*=(), QMargins::operator/=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn const QMargins operator*(const QMargins &margins, qreal factor)
+    \relates QMargins
+    \overload
+
+    Returns a QMargins object that is formed by multiplying each component
+    of the given \a margins by \a factor.
+
+    \sa QMargins::operator*=(), QMargins::operator/=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn const QMargins operator*(qreal factor, const QMargins &margins)
+    \relates QMargins
+    \overload
+
+    Returns a QMargins object that is formed by multiplying each component
+    of the given \a margins by \a factor.
+
+    \sa QMargins::operator*=(), QMargins::operator/=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn const QMargins operator/(const QMargins &margins, int divisor)
+    \relates QMargins
+
+    Returns a QMargins object that is formed by dividing the components of
+    the given \a margins by the given \a divisor.
+
+    \sa QMargins::operator*=(), QMargins::operator/=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn const QMargins operator/(const QMargins &, qreal)
+    \relates QMargins
+    \overload
+
+    Returns a QMargins object that is formed by dividing the components of
+    the given \a margins by the given \a divisor.
+
+    \sa QMargins::operator*=(), QMargins::operator/=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn QMargins operator-(const QMargins &margins)
+    \relates QMargins
+
+    Returns a QMargin object that is formed by negating all components of \a margins.
+
+    \since 5.1
+*/
+
+/*!
+    \fn QMargins &operator+=(const QMargins &margins)
+
+    Add each component of \a margins to the respective component of this object
+    and returns a reference to it.
+
+    \sa operator-=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn QMargins &operator-=(const QMargins &margins)
+
+    Subtract each component of \a margins from the respective component of this object
+    and returns a reference to it.
+
+    \sa operator+=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn QMargins &operator*=(int factor)
+
+    Multiplies each component of this object by \a factor
+    and returns a reference to it.
+
+    \sa operator/=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn QMargins &operator*=(qreal factor)
+    \overload
+
+    Multiplies each component of this object by \a factor
+    and returns a reference to it.
+
+    \sa operator/=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn QMargins &operator/=(int divisor)
+
+    Divides each component of this object by \a divisor
+    and returns a reference to it.
+
+    \sa operator*=()
+
+    \since 5.1
+*/
+
+/*!
+    \fn QMargins &operator/=(qreal divisor)
+
+    \overload
+
+    \sa operator*=()
+
+    \since 5.1
+*/
+
 /*****************************************************************************
   QMargins stream functions
  *****************************************************************************/
diff --git a/src/corelib/tools/qmargins.h b/src/corelib/tools/qmargins.h
index a933a60fed..dd6fb0261a 100644
--- a/src/corelib/tools/qmargins.h
+++ b/src/corelib/tools/qmargins.h
@@ -67,6 +67,15 @@ public:
     void setRight(int right);
     void setBottom(int bottom);
 
+    QMargins &operator+=(const QMargins &margins);
+    QMargins &operator-=(const QMargins &margins);
+    QMargins &operator+=(int);
+    QMargins &operator-=(int);
+    QMargins &operator*=(int);
+    QMargins &operator/=(int);
+    QMargins &operator*=(qreal);
+    QMargins &operator/=(qreal);
+
 private:
     int m_left;
     int m_top;
@@ -177,6 +186,89 @@ inline QRect &QRect::operator-=(const QMargins &margins)
     return *this;
 }
 
+Q_DECL_CONSTEXPR inline QMargins operator+(const QMargins &m1, const QMargins &m2)
+{
+    return QMargins(m1.left() + m2.left(), m1.top() + m2.top(),
+                    m1.right() + m2.right(), m1.bottom() + m2.bottom());
+}
+
+Q_DECL_CONSTEXPR inline QMargins operator-(const QMargins &m1, const QMargins &m2)
+{
+    return QMargins(m1.left() - m2.left(), m1.top() - m2.top(),
+                    m1.right() - m2.right(), m1.bottom() - m2.bottom());
+}
+
+Q_DECL_CONSTEXPR inline QMargins operator*(const QMargins &margins, int factor)
+{
+    return QMargins(margins.left() * factor, margins.top() * factor,
+                    margins.right() * factor, margins.bottom() * factor);
+}
+
+Q_DECL_CONSTEXPR inline QMargins operator*(int factor, const QMargins &margins)
+{
+    return QMargins(margins.left() * factor, margins.top() * factor,
+                    margins.right() * factor, margins.bottom() * factor);
+}
+
+Q_DECL_CONSTEXPR inline QMargins operator*(const QMargins &margins, qreal factor)
+{
+    return QMargins(qRound(margins.left() * factor), qRound(margins.top() * factor),
+                    qRound(margins.right() * factor), qRound(margins.bottom() * factor));
+}
+
+Q_DECL_CONSTEXPR inline QMargins operator*(qreal factor, const QMargins &margins)
+{
+    return QMargins(qRound(margins.left() * factor), qRound(margins.top() * factor),
+                    qRound(margins.right() * factor), qRound(margins.bottom() * factor));
+}
+
+Q_DECL_CONSTEXPR inline QMargins operator/(const QMargins &margins, int divisor)
+{
+    return QMargins(margins.left() / divisor, margins.top() / divisor,
+                    margins.right() / divisor, margins.bottom() / divisor);
+}
+
+Q_DECL_CONSTEXPR inline QMargins operator/(const QMargins &margins, qreal divisor)
+{
+    return QMargins(qRound(margins.left() / divisor), qRound(margins.top() / divisor),
+                    qRound(margins.right() / divisor), qRound(margins.bottom() / divisor));
+}
+
+inline QMargins &QMargins::operator+=(const QMargins &margins)
+{
+    return *this = *this + margins;
+}
+
+inline QMargins &QMargins::operator-=(const QMargins &margins)
+{
+    return *this = *this - margins;
+}
+
+inline QMargins &QMargins::operator*=(int factor)
+{
+    return *this = *this * factor;
+}
+
+inline QMargins &QMargins::operator/=(int divisor)
+{
+    return *this = *this / divisor;
+}
+
+inline QMargins &QMargins::operator*=(qreal factor)
+{
+    return *this = *this * factor;
+}
+
+inline QMargins &QMargins::operator/=(qreal divisor)
+{
+    return *this = *this / divisor;
+}
+
+Q_DECL_CONSTEXPR inline QMargins operator-(const QMargins &margins)
+{
+    return QMargins(-margins.left(), -margins.top(), -margins.right(), -margins.bottom());
+}
+
 #ifndef QT_NO_DEBUG_STREAM
 Q_CORE_EXPORT QDebug operator<<(QDebug, const QMargins &);
 #endif