QQuaternion: make methods constexpr, noexcept; fix style

The class stores all data inline, and most member functions are inline
already with trivial arithmetic operations on those data members. So we
can make the class almost completely constexpr. This includes member
functions that construct or use QVector3D/4D, as those types are also
fully constexpr.

Almost all inline (and now constexpr) member functions can then also be
made noexcept, with the exception of the division operators that don't
check the divisor for 0. qFuzzyCompare(float, float) is not noexcept,
but it has no preconditions and never throws, so we can make the
QQuaternion overload noexcept.

Remove const from values returned by arithmetic operators, and fix
whitespace style in prototypes (also the few that are not already
touched by the other changes).

Prepare unexporting the class wholesale in Qt 7; we only have to
export out-of-line functions, but can't make that change in Qt 6,
as the implicitly defined special member functions are exported (at
least on MSVC).

Change-Id: I3e43232bf66009352e8de937c07b2985147fb33c
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Sami Varanka <sami.varanka@qt.io>

2 files changed, 137 insertions, 136 deletions

diff --git a/src/gui/math3d/qquaternion.cpp b/src/gui/math3d/qquaternion.cpp
index f546d63a72..e7c5945208 100644
--- a/src/gui/math3d/qquaternion.cpp
+++ b/src/gui/math3d/qquaternion.cpp
@@ -26,14 +26,14 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QQuaternion::QQuaternion()
+    \fn QQuaternion::QQuaternion() noexcept
 
     Constructs an identity quaternion (1, 0, 0, 0), i.e. with the vector (0, 0, 0)
     and scalar 1.
 */
 
 /*!
-    \fn QQuaternion::QQuaternion(Qt::Initialization)
+    \fn QQuaternion::QQuaternion(Qt::Initialization) noexcept
     \since 5.5
     \internal
 
@@ -41,7 +41,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QQuaternion::QQuaternion(float scalar, float xpos, float ypos, float zpos)
+    \fn QQuaternion::QQuaternion(float scalar, float xpos, float ypos, float zpos) noexcept
 
     Constructs a quaternion with the vector (\a xpos, \a ypos, \a zpos)
     and \a scalar.
@@ -50,7 +50,7 @@ QT_BEGIN_NAMESPACE
 #ifndef QT_NO_VECTOR3D
 
 /*!
-    \fn QQuaternion::QQuaternion(float scalar, const QVector3D& vector)
+    \fn QQuaternion::QQuaternion(float scalar, const QVector3D &vector) noexcept
 
     Constructs a quaternion vector from the specified \a vector and
     \a scalar.
@@ -59,7 +59,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn QVector3D QQuaternion::vector() const
+    \fn QVector3D QQuaternion::vector() const noexcept
 
     Returns the vector component of this quaternion.
 
@@ -67,7 +67,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn void QQuaternion::setVector(const QVector3D& vector)
+    \fn void QQuaternion::setVector(const QVector3D &vector) noexcept
 
     Sets the vector component of this quaternion to \a vector.
 
@@ -77,7 +77,7 @@ QT_BEGIN_NAMESPACE
 #endif
 
 /*!
-    \fn void QQuaternion::setVector(float x, float y, float z)
+    \fn void QQuaternion::setVector(float x, float y, float z) noexcept
 
     Sets the vector component of this quaternion to (\a x, \a y, \a z).
 
@@ -87,13 +87,13 @@ QT_BEGIN_NAMESPACE
 #ifndef QT_NO_VECTOR4D
 
 /*!
-    \fn QQuaternion::QQuaternion(const QVector4D& vector)
+    \fn QQuaternion::QQuaternion(const QVector4D &vector) noexcept
 
     Constructs a quaternion from the components of \a vector.
 */
 
 /*!
-    \fn QVector4D QQuaternion::toVector4D() const
+    \fn QVector4D QQuaternion::toVector4D() const noexcept
 
     Returns this quaternion as a 4D vector.
 */
@@ -101,14 +101,14 @@ QT_BEGIN_NAMESPACE
 #endif
 
 /*!
-    \fn bool QQuaternion::isNull() const
+    \fn bool QQuaternion::isNull() const noexcept
 
     Returns \c true if the x, y, z, and scalar components of this
     quaternion are set to 0.0; otherwise returns \c false.
 */
 
 /*!
-    \fn bool QQuaternion::isIdentity() const
+    \fn bool QQuaternion::isIdentity() const noexcept
 
     Returns \c true if the x, y, and z components of this
     quaternion are set to 0.0, and the scalar component is set
@@ -116,7 +116,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn float QQuaternion::x() const
+    \fn float QQuaternion::x() const noexcept
 
     Returns the x coordinate of this quaternion's vector.
 
@@ -124,7 +124,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn float QQuaternion::y() const
+    \fn float QQuaternion::y() const noexcept
 
     Returns the y coordinate of this quaternion's vector.
 
@@ -132,7 +132,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn float QQuaternion::z() const
+    \fn float QQuaternion::z() const noexcept
 
     Returns the z coordinate of this quaternion's vector.
 
@@ -140,7 +140,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn float QQuaternion::scalar() const
+    \fn float QQuaternion::scalar() const noexcept
 
     Returns the scalar component of this quaternion.
 
@@ -148,7 +148,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn void QQuaternion::setX(float x)
+    \fn void QQuaternion::setX(float x) noexcept
 
     Sets the x coordinate of this quaternion's vector to the given
     \a x coordinate.
@@ -157,7 +157,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn void QQuaternion::setY(float y)
+    \fn void QQuaternion::setY(float y) noexcept
 
     Sets the y coordinate of this quaternion's vector to the given
     \a y coordinate.
@@ -166,7 +166,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn void QQuaternion::setZ(float z)
+    \fn void QQuaternion::setZ(float z) noexcept
 
     Sets the z coordinate of this quaternion's vector to the given
     \a z coordinate.
@@ -175,7 +175,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn void QQuaternion::setScalar(float scalar)
+    \fn void QQuaternion::setScalar(float scalar) noexcept
 
     Sets the scalar component of this quaternion to \a scalar.
 
@@ -183,7 +183,7 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-    \fn float QQuaternion::dotProduct(const QQuaternion &q1, const QQuaternion &q2)
+    \fn float QQuaternion::dotProduct(const QQuaternion &q1, const QQuaternion &q2) noexcept
     \since 5.5
 
     Returns the dot product of \a q1 and \a q2.
@@ -251,7 +251,7 @@ void QQuaternion::normalize()
 }
 
 /*!
-    \fn QQuaternion QQuaternion::inverted() const
+    \fn QQuaternion QQuaternion::inverted() const noexcept
     \since 5.5
 
     Returns the inverse of this quaternion.
@@ -261,7 +261,7 @@ void QQuaternion::normalize()
 */
 
 /*!
-    \fn QQuaternion QQuaternion::conjugated() const
+    \fn QQuaternion QQuaternion::conjugated() const noexcept
     \since 5.5
 
     Returns the conjugate of this quaternion, which is
@@ -278,13 +278,13 @@ void QQuaternion::normalize()
 
     \snippet code/src_gui_math3d_qquaternion.cpp 1
 */
-QVector3D QQuaternion::rotatedVector(const QVector3D& vector) const
+QVector3D QQuaternion::rotatedVector(const QVector3D &vector) const
 {
     return (*this * QQuaternion(0, vector) * conjugated()).vector();
 }
 
 /*!
-    \fn QQuaternion &QQuaternion::operator+=(const QQuaternion &quaternion)
+    \fn QQuaternion &QQuaternion::operator+=(const QQuaternion &quaternion) noexcept
 
     Adds the given \a quaternion to this quaternion and returns a reference to
     this quaternion.
@@ -293,7 +293,7 @@ QVector3D QQuaternion::rotatedVector(const QVector3D& vector) const
 */
 
 /*!
-    \fn QQuaternion &QQuaternion::operator-=(const QQuaternion &quaternion)
+    \fn QQuaternion &QQuaternion::operator-=(const QQuaternion &quaternion) noexcept
 
     Subtracts the given \a quaternion from this quaternion and returns a
     reference to this quaternion.
@@ -302,7 +302,7 @@ QVector3D QQuaternion::rotatedVector(const QVector3D& vector) const
 */
 
 /*!
-    \fn QQuaternion &QQuaternion::operator*=(float factor)
+    \fn QQuaternion &QQuaternion::operator*=(float factor) noexcept
 
     Multiplies this quaternion's components by the given \a factor, and
     returns a reference to this quaternion.
@@ -311,7 +311,7 @@ QVector3D QQuaternion::rotatedVector(const QVector3D& vector) const
 */
 
 /*!
-    \fn QQuaternion &QQuaternion::operator*=(const QQuaternion &quaternion)
+    \fn QQuaternion &QQuaternion::operator*=(const QQuaternion &quaternion) noexcept
 
     Multiplies this quaternion by \a quaternion and returns a reference
     to this quaternion.
@@ -329,7 +329,7 @@ QVector3D QQuaternion::rotatedVector(const QVector3D& vector) const
 #ifndef QT_NO_VECTOR3D
 
 /*!
-    \fn void QQuaternion::getAxisAndAngle(QVector3D *axis, float *angle) const
+    \fn void QQuaternion::getAxisAndAngle(QVector3D *axis, float *angle) const noexcept
     \since 5.5
     \overload
 
@@ -345,7 +345,7 @@ QVector3D QQuaternion::rotatedVector(const QVector3D& vector) const
 
     \sa getAxisAndAngle()
 */
-QQuaternion QQuaternion::fromAxisAndAngle(const QVector3D& axis, float angle)
+QQuaternion QQuaternion::fromAxisAndAngle(const QVector3D &axis, float angle)
 {
     // Algorithm from:
     // http://www.j3d.org/matrix_faq/matrfaq_latest.html#Q56
@@ -738,21 +738,21 @@ QQuaternion QQuaternion::rotationTo(const QVector3D &from, const QVector3D &to)
 #endif // QT_NO_VECTOR3D
 
 /*!
-    \fn bool QQuaternion::operator==(const QQuaternion &q1, const QQuaternion &q2)
+    \fn bool QQuaternion::operator==(const QQuaternion &q1, const QQuaternion &q2) noexcept
 
     Returns \c true if \a q1 is equal to \a q2; otherwise returns \c false.
     This operator uses an exact floating-point comparison.
 */
 
 /*!
-    \fn bool QQuaternion::operator!=(const QQuaternion &q1, const QQuaternion &q2)
+    \fn bool QQuaternion::operator!=(const QQuaternion &q1, const QQuaternion &q2) noexcept
 
     Returns \c true if \a q1 is not equal to \a q2; otherwise returns \c false.
     This operator uses an exact floating-point comparison.
 */
 
 /*!
-    \fn const QQuaternion operator+(const QQuaternion &q1, const QQuaternion &q2)
+    \fn const QQuaternion operator+(const QQuaternion &q1, const QQuaternion &q2) noexcept
     \relates QQuaternion
 
     Returns a QQuaternion object that is the sum of the given quaternions,
@@ -762,7 +762,7 @@ QQuaternion QQuaternion::rotationTo(const QVector3D &from, const QVector3D &to)
 */
 
 /*!
-    \fn const QQuaternion operator-(const QQuaternion &q1, const QQuaternion &q2)
+    \fn const QQuaternion operator-(const QQuaternion &q1, const QQuaternion &q2) noexcept
     \relates QQuaternion
 
     Returns a QQuaternion object that is formed by subtracting
@@ -772,7 +772,7 @@ QQuaternion QQuaternion::rotationTo(const QVector3D &from, const QVector3D &to)
 */
 
 /*!
-    \fn const QQuaternion operator*(float factor, const QQuaternion &quaternion)
+    \fn const QQuaternion operator*(float factor, const QQuaternion &quaternion) noexcept
     \relates QQuaternion
 
     Returns a copy of the given \a quaternion,  multiplied by the
@@ -782,7 +782,7 @@ QQuaternion QQuaternion::rotationTo(const QVector3D &from, const QVector3D &to)
 */
 
 /*!
-    \fn const QQuaternion operator*(const QQuaternion &quaternion, float factor)
+    \fn const QQuaternion operator*(const QQuaternion &quaternion, float factor) noexcept
     \relates QQuaternion
 
     Returns a copy of the given \a quaternion,  multiplied by the
@@ -792,7 +792,7 @@ QQuaternion QQuaternion::rotationTo(const QVector3D &from, const QVector3D &to)
 */
 
 /*!
-    \fn const QQuaternion operator*(const QQuaternion &q1, const QQuaternion& q2)
+    \fn const QQuaternion operator*(const QQuaternion &q1, const QQuaternion &q2) noexcept
     \relates QQuaternion
 
     Multiplies \a q1 and \a q2 using quaternion multiplication.
@@ -803,7 +803,7 @@ QQuaternion QQuaternion::rotationTo(const QVector3D &from, const QVector3D &to)
 */
 
 /*!
-    \fn const QQuaternion operator-(const QQuaternion &quaternion)
+    \fn const QQuaternion operator-(const QQuaternion &quaternion) noexcept
     \relates QQuaternion
     \overload
 
@@ -826,7 +826,7 @@ QQuaternion QQuaternion::rotationTo(const QVector3D &from, const QVector3D &to)
 #ifndef QT_NO_VECTOR3D
 
 /*!
-    \fn QVector3D operator*(const QQuaternion &quaternion, const QVector3D &vec)
+    \fn QVector3D operator*(const QQuaternion &quaternion, const QVector3D &vec) noexcept
     \since 5.5
     \relates QQuaternion
 
@@ -836,7 +836,7 @@ QQuaternion QQuaternion::rotationTo(const QVector3D &from, const QVector3D &to)
 #endif
 
 /*!
-    \fn bool qFuzzyCompare(const QQuaternion& q1, const QQuaternion& q2)
+    \fn bool qFuzzyCompare(const QQuaternion &q1, const QQuaternion &q2) noexcept
     \relates QQuaternion
 
     Returns \c true if \a q1 and \a q2 are equal, allowing for a small
@@ -855,7 +855,7 @@ QQuaternion QQuaternion::rotationTo(const QVector3D &from, const QVector3D &to)
     \sa nlerp()
 */
 QQuaternion QQuaternion::slerp
-    (const QQuaternion& q1, const QQuaternion& q2, float t)
+    (const QQuaternion &q1, const QQuaternion &q2, float t)
 {
     // Handle the easy cases first.
     if (t <= 0.0f)
@@ -904,7 +904,7 @@ QQuaternion QQuaternion::slerp
     \sa slerp()
 */
 QQuaternion QQuaternion::nlerp
-    (const QQuaternion& q1, const QQuaternion& q2, float t)
+    (const QQuaternion &q1, const QQuaternion &q2, float t)
 {
     // Handle the easy cases first.
     if (t <= 0.0f)
diff --git a/src/gui/math3d/qquaternion.h b/src/gui/math3d/qquaternion.h
index 226a077d4c..e6456e6e27 100644
--- a/src/gui/math3d/qquaternion.h
+++ b/src/gui/math3d/qquaternion.h
@@ -17,117 +17,117 @@ QT_BEGIN_NAMESPACE
 class QMatrix4x4;
 class QVariant;
 
-class Q_GUI_EXPORT QQuaternion
+class QT6_ONLY(Q_GUI_EXPORT) QQuaternion
 {
 public:
-    QQuaternion();
-    explicit QQuaternion(Qt::Initialization) {}
-    QQuaternion(float scalar, float xpos, float ypos, float zpos);
+    constexpr QQuaternion() noexcept;
+    explicit QQuaternion(Qt::Initialization) noexcept {}
+    constexpr QQuaternion(float scalar, float xpos, float ypos, float zpos) noexcept;
 #ifndef QT_NO_VECTOR3D
-    QQuaternion(float scalar, const QVector3D& vector);
+    constexpr QQuaternion(float scalar, const QVector3D &vector) noexcept;
 #endif
 #ifndef QT_NO_VECTOR4D
-    explicit QQuaternion(const QVector4D& vector);
+    constexpr explicit QQuaternion(const QVector4D &vector) noexcept;
 #endif
 
-    bool isNull() const;
-    bool isIdentity() const;
+    constexpr bool isNull() const noexcept;
+    constexpr bool isIdentity() const noexcept;
 
 #ifndef QT_NO_VECTOR3D
-    QVector3D vector() const;
-    void setVector(const QVector3D& vector);
+    constexpr QVector3D vector() const noexcept;
+    constexpr void setVector(const QVector3D &vector) noexcept;
 #endif
-    void setVector(float x, float y, float z);
+    constexpr void setVector(float x, float y, float z) noexcept;
 
-    float x() const;
-    float y() const;
-    float z() const;
-    float scalar() const;
+    constexpr float x() const noexcept;
+    constexpr float y() const noexcept;
+    constexpr float z() const noexcept;
+    constexpr float scalar() const noexcept;
 
-    void setX(float x);
-    void setY(float y);
-    void setZ(float z);
-    void setScalar(float scalar);
+    constexpr void setX(float x) noexcept;
+    constexpr void setY(float y) noexcept;
+    constexpr void setZ(float z) noexcept;
+    constexpr void setScalar(float scalar) noexcept;
 
-    constexpr static inline float dotProduct(const QQuaternion &q1, const QQuaternion &q2);
+    constexpr static float dotProduct(const QQuaternion &q1, const QQuaternion &q2) noexcept;
 
-    float length() const;
-    float lengthSquared() const;
+    // ### Qt 7: make the next four constexpr
+    // (perhaps using std::hypot, constexpr in C++26, or constexpr qHypot)
+    QT7_ONLY(Q_GUI_EXPORT) float length() const;
+    QT7_ONLY(Q_GUI_EXPORT) float lengthSquared() const;
 
-    [[nodiscard]] QQuaternion normalized() const;
-    void normalize();
+    [[nodiscard]] QT7_ONLY(Q_GUI_EXPORT) QQuaternion normalized() const;
+   QT7_ONLY(Q_GUI_EXPORT)  void normalize();
 
-    inline QQuaternion inverted() const;
+    constexpr QQuaternion inverted() const noexcept;
 
-    [[nodiscard]] QQuaternion conjugated() const;
+    [[nodiscard]] constexpr QQuaternion conjugated() const noexcept;
 
-    QVector3D rotatedVector(const QVector3D& vector) const;
+    QT7_ONLY(Q_GUI_EXPORT) QVector3D rotatedVector(const QVector3D &vector) const;
 
-    QQuaternion &operator+=(const QQuaternion &quaternion);
-    QQuaternion &operator-=(const QQuaternion &quaternion);
-    QQuaternion &operator*=(float factor);
-    QQuaternion &operator*=(const QQuaternion &quaternion);
-    QQuaternion &operator/=(float divisor);
+    constexpr QQuaternion &operator+=(const QQuaternion &quaternion) noexcept;
+    constexpr QQuaternion &operator-=(const QQuaternion &quaternion) noexcept;
+    constexpr QQuaternion &operator*=(float factor) noexcept;
+    constexpr QQuaternion &operator*=(const QQuaternion &quaternion) noexcept;
+    constexpr QQuaternion &operator/=(float divisor);
 
 QT_WARNING_PUSH
 QT_WARNING_DISABLE_FLOAT_COMPARE
-    friend inline bool operator==(const QQuaternion &q1, const QQuaternion &q2) noexcept
+    friend constexpr bool operator==(const QQuaternion &q1, const QQuaternion &q2) noexcept
     {
         return q1.wp == q2.wp && q1.xp == q2.xp && q1.yp == q2.yp && q1.zp == q2.zp;
     }
-    friend inline bool operator!=(const QQuaternion &q1, const QQuaternion &q2) noexcept
+    friend constexpr bool operator!=(const QQuaternion &q1, const QQuaternion &q2) noexcept
     {
         return !(q1 == q2);
     }
 QT_WARNING_POP
 
-    friend inline const QQuaternion operator+(const QQuaternion &q1, const QQuaternion &q2);
-    friend inline const QQuaternion operator-(const QQuaternion &q1, const QQuaternion &q2);
-    friend inline const QQuaternion operator*(float factor, const QQuaternion &quaternion);
-    friend inline const QQuaternion operator*(const QQuaternion &quaternion, float factor);
-    friend inline const QQuaternion operator*(const QQuaternion &q1, const QQuaternion& q2);
-    friend inline const QQuaternion operator-(const QQuaternion &quaternion);
-    friend inline const QQuaternion operator/(const QQuaternion &quaternion, float divisor);
+    friend constexpr QQuaternion operator+(const QQuaternion &q1, const QQuaternion &q2) noexcept;
+    friend constexpr QQuaternion operator-(const QQuaternion &q1, const QQuaternion &q2) noexcept;
+    friend constexpr QQuaternion operator*(float factor, const QQuaternion &quaternion) noexcept;
+    friend constexpr QQuaternion operator*(const QQuaternion &quaternion, float factor) noexcept;
+    friend constexpr QQuaternion operator*(const QQuaternion &q1, const QQuaternion &q2) noexcept;
+    friend constexpr QQuaternion operator-(const QQuaternion &quaternion) noexcept;
+    friend constexpr QQuaternion operator/(const QQuaternion &quaternion, float divisor);
 
-    friend inline bool qFuzzyCompare(const QQuaternion& q1, const QQuaternion& q2);
+    friend constexpr bool qFuzzyCompare(const QQuaternion &q1, const QQuaternion &q2) noexcept;
 
 #ifndef QT_NO_VECTOR4D
-    QVector4D toVector4D() const;
+    constexpr QVector4D toVector4D() const noexcept;
 #endif
 
-    operator QVariant() const;
+    QT7_ONLY(Q_GUI_EXPORT) operator QVariant() const;
 
 #ifndef QT_NO_VECTOR3D
     inline void getAxisAndAngle(QVector3D *axis, float *angle) const;
-    static QQuaternion fromAxisAndAngle(const QVector3D& axis, float angle);
+    QT7_ONLY(Q_GUI_EXPORT) static QQuaternion fromAxisAndAngle(const QVector3D &axis, float angle);
 #endif
-    void getAxisAndAngle(float *x, float *y, float *z, float *angle) const;
-    static QQuaternion fromAxisAndAngle
-            (float x, float y, float z, float angle);
+    QT7_ONLY(Q_GUI_EXPORT) void getAxisAndAngle(float *x, float *y, float *z, float *angle) const;
+    QT7_ONLY(Q_GUI_EXPORT) static QQuaternion fromAxisAndAngle(float x, float y, float z, float angle);
 
 #ifndef QT_NO_VECTOR3D
     inline QVector3D toEulerAngles() const;
-    static inline QQuaternion fromEulerAngles(const QVector3D &eulerAngles);
+    QT7_ONLY(Q_GUI_EXPORT) static inline QQuaternion fromEulerAngles(const QVector3D &eulerAngles);
 #endif
-    void getEulerAngles(float *pitch, float *yaw, float *roll) const;
-    static QQuaternion fromEulerAngles(float pitch, float yaw, float roll);
+    QT7_ONLY(Q_GUI_EXPORT) void getEulerAngles(float *pitch, float *yaw, float *roll) const;
+    QT7_ONLY(Q_GUI_EXPORT) static QQuaternion fromEulerAngles(float pitch, float yaw, float roll);
 
-    QMatrix3x3 toRotationMatrix() const;
-    static QQuaternion fromRotationMatrix(const QMatrix3x3 &rot3x3);
+    QT7_ONLY(Q_GUI_EXPORT) QMatrix3x3 toRotationMatrix() const;
+    QT7_ONLY(Q_GUI_EXPORT) static QQuaternion fromRotationMatrix(const QMatrix3x3 &rot3x3);
 
 #ifndef QT_NO_VECTOR3D
-    void getAxes(QVector3D *xAxis, QVector3D *yAxis, QVector3D *zAxis) const;
-    static QQuaternion fromAxes(const QVector3D &xAxis, const QVector3D &yAxis, const QVector3D &zAxis);
+    QT7_ONLY(Q_GUI_EXPORT) void getAxes(QVector3D *xAxis, QVector3D *yAxis, QVector3D *zAxis) const;
+    QT7_ONLY(Q_GUI_EXPORT) static QQuaternion fromAxes(const QVector3D &xAxis, const QVector3D &yAxis,
+                                                       const QVector3D &zAxis);
 
-    static QQuaternion fromDirection(const QVector3D &direction, const QVector3D &up);
+    QT7_ONLY(Q_GUI_EXPORT) static QQuaternion fromDirection(const QVector3D &direction, const QVector3D &up);
 
-    static QQuaternion rotationTo(const QVector3D &from, const QVector3D &to);
+    QT7_ONLY(Q_GUI_EXPORT) static QQuaternion rotationTo(const QVector3D &from, const QVector3D &to);
 #endif
 
-    static QQuaternion slerp
-        (const QQuaternion& q1, const QQuaternion& q2, float t);
-    static QQuaternion nlerp
-        (const QQuaternion& q1, const QQuaternion& q2, float t);
+    QT7_ONLY(Q_GUI_EXPORT) static QQuaternion slerp(const QQuaternion &q1, const QQuaternion &q2, float t);
+    QT7_ONLY(Q_GUI_EXPORT) static QQuaternion nlerp(const QQuaternion &q1, const QQuaternion &q2, float t);
 
 private:
     float wp, xp, yp, zp;
@@ -135,40 +135,41 @@ private:
 
 Q_DECLARE_TYPEINFO(QQuaternion, Q_PRIMITIVE_TYPE);
 
-inline QQuaternion::QQuaternion() : wp(1.0f), xp(0.0f), yp(0.0f), zp(0.0f) {}
+constexpr QQuaternion::QQuaternion() noexcept : wp(1.0f), xp(0.0f), yp(0.0f), zp(0.0f) {}
 
-inline QQuaternion::QQuaternion(float aScalar, float xpos, float ypos, float zpos) : wp(aScalar), xp(xpos), yp(ypos), zp(zpos) {}
+constexpr QQuaternion::QQuaternion(float aScalar, float xpos, float ypos, float zpos) noexcept
+    : wp(aScalar), xp(xpos), yp(ypos), zp(zpos) {}
 
 QT_WARNING_PUSH
 QT_WARNING_DISABLE_FLOAT_COMPARE
 
-inline bool QQuaternion::isNull() const
+constexpr bool QQuaternion::isNull() const noexcept
 {
     return wp == 0.0f && xp == 0.0f && yp == 0.0f && zp == 0.0f;
 }
 
-inline bool QQuaternion::isIdentity() const
+constexpr bool QQuaternion::isIdentity() const noexcept
 {
     return wp == 1.0f && xp == 0.0f && yp == 0.0f && zp == 0.0f;
 }
 QT_WARNING_POP
 
-inline float QQuaternion::x() const { return xp; }
-inline float QQuaternion::y() const { return yp; }
-inline float QQuaternion::z() const { return zp; }
-inline float QQuaternion::scalar() const { return wp; }
+constexpr float QQuaternion::x() const noexcept { return xp; }
+constexpr float QQuaternion::y() const noexcept { return yp; }
+constexpr float QQuaternion::z() const noexcept { return zp; }
+constexpr float QQuaternion::scalar() const noexcept { return wp; }
 
-inline void QQuaternion::setX(float aX) { xp = aX; }
-inline void QQuaternion::setY(float aY) { yp = aY; }
-inline void QQuaternion::setZ(float aZ) { zp = aZ; }
-inline void QQuaternion::setScalar(float aScalar) { wp = aScalar; }
+constexpr void QQuaternion::setX(float aX) noexcept { xp = aX; }
+constexpr void QQuaternion::setY(float aY) noexcept { yp = aY; }
+constexpr void QQuaternion::setZ(float aZ) noexcept { zp = aZ; }
+constexpr void QQuaternion::setScalar(float aScalar) noexcept { wp = aScalar; }
 
-constexpr inline float QQuaternion::dotProduct(const QQuaternion &q1, const QQuaternion &q2)
+constexpr float QQuaternion::dotProduct(const QQuaternion &q1, const QQuaternion &q2) noexcept
 {
     return q1.wp * q2.wp + q1.xp * q2.xp + q1.yp * q2.yp + q1.zp * q2.zp;
 }
 
-inline QQuaternion QQuaternion::inverted() const
+constexpr QQuaternion QQuaternion::inverted() const noexcept
 {
     // Need some extra precision if the length is very small.
     double len = double(wp) * double(wp) +
@@ -181,12 +182,12 @@ inline QQuaternion QQuaternion::inverted() const
     return QQuaternion(0.0f, 0.0f, 0.0f, 0.0f);
 }
 
-inline QQuaternion QQuaternion::conjugated() const
+constexpr QQuaternion QQuaternion::conjugated() const noexcept
 {
     return QQuaternion(wp, -xp, -yp, -zp);
 }
 
-inline QQuaternion &QQuaternion::operator+=(const QQuaternion &quaternion)
+constexpr QQuaternion &QQuaternion::operator+=(const QQuaternion &quaternion) noexcept
 {
     wp += quaternion.wp;
     xp += quaternion.xp;
@@ -195,7 +196,7 @@ inline QQuaternion &QQuaternion::operator+=(const QQuaternion &quaternion)
     return *this;
 }
 
-inline QQuaternion &QQuaternion::operator-=(const QQuaternion &quaternion)
+constexpr QQuaternion &QQuaternion::operator-=(const QQuaternion &quaternion) noexcept
 {
     wp -= quaternion.wp;
     xp -= quaternion.xp;
@@ -204,7 +205,7 @@ inline QQuaternion &QQuaternion::operator-=(const QQuaternion &quaternion)
     return *this;
 }
 
-inline QQuaternion &QQuaternion::operator*=(float factor)
+constexpr QQuaternion &QQuaternion::operator*=(float factor) noexcept
 {
     wp *= factor;
     xp *= factor;
@@ -213,7 +214,7 @@ inline QQuaternion &QQuaternion::operator*=(float factor)
     return *this;
 }
 
-inline const QQuaternion operator*(const QQuaternion &q1, const QQuaternion& q2)
+constexpr QQuaternion operator*(const QQuaternion &q1, const QQuaternion &q2) noexcept
 {
     float yy = (q1.wp - q1.yp) * (q2.wp + q2.zp);
     float zz = (q1.wp + q1.yp) * (q2.wp - q2.zp);
@@ -229,13 +230,13 @@ inline const QQuaternion operator*(const QQuaternion &q1, const QQuaternion& q2)
     return QQuaternion(w, x, y, z);
 }
 
-inline QQuaternion &QQuaternion::operator*=(const QQuaternion &quaternion)
+constexpr QQuaternion &QQuaternion::operator*=(const QQuaternion &quaternion) noexcept
 {
     *this = *this * quaternion;
     return *this;
 }
 
-inline QQuaternion &QQuaternion::operator/=(float divisor)
+constexpr QQuaternion &QQuaternion::operator/=(float divisor)
 {
     wp /= divisor;
     xp /= divisor;
@@ -244,37 +245,37 @@ inline QQuaternion &QQuaternion::operator/=(float divisor)
     return *this;
 }
 
-inline const QQuaternion operator+(const QQuaternion &q1, const QQuaternion &q2)
+constexpr QQuaternion operator+(const QQuaternion &q1, const QQuaternion &q2) noexcept
 {
     return QQuaternion(q1.wp + q2.wp, q1.xp + q2.xp, q1.yp + q2.yp, q1.zp + q2.zp);
 }
 
-inline const QQuaternion operator-(const QQuaternion &q1, const QQuaternion &q2)
+constexpr QQuaternion operator-(const QQuaternion &q1, const QQuaternion &q2) noexcept
 {
     return QQuaternion(q1.wp - q2.wp, q1.xp - q2.xp, q1.yp - q2.yp, q1.zp - q2.zp);
 }
 
-inline const QQuaternion operator*(float factor, const QQuaternion &quaternion)
+constexpr QQuaternion operator*(float factor, const QQuaternion &quaternion) noexcept
 {
     return QQuaternion(quaternion.wp * factor, quaternion.xp * factor, quaternion.yp * factor, quaternion.zp * factor);
 }
 
-inline const QQuaternion operator*(const QQuaternion &quaternion, float factor)
+constexpr QQuaternion operator*(const QQuaternion &quaternion, float factor) noexcept
 {
     return QQuaternion(quaternion.wp * factor, quaternion.xp * factor, quaternion.yp * factor, quaternion.zp * factor);
 }
 
-inline const QQuaternion operator-(const QQuaternion &quaternion)
+constexpr QQuaternion operator-(const QQuaternion &quaternion) noexcept
 {
     return QQuaternion(-quaternion.wp, -quaternion.xp, -quaternion.yp, -quaternion.zp);
 }
 
-inline const QQuaternion operator/(const QQuaternion &quaternion, float divisor)
+constexpr QQuaternion operator/(const QQuaternion &quaternion, float divisor)
 {
     return QQuaternion(quaternion.wp / divisor, quaternion.xp / divisor, quaternion.yp / divisor, quaternion.zp / divisor);
 }
 
-inline bool qFuzzyCompare(const QQuaternion& q1, const QQuaternion& q2)
+constexpr bool qFuzzyCompare(const QQuaternion &q1, const QQuaternion &q2) noexcept
 {
     return qFuzzyCompare(q1.wp, q2.wp) &&
            qFuzzyCompare(q1.xp, q2.xp) &&
@@ -284,17 +285,17 @@ inline bool qFuzzyCompare(const QQuaternion& q1, const QQuaternion& q2)
 
 #ifndef QT_NO_VECTOR3D
 
-inline QQuaternion::QQuaternion(float aScalar, const QVector3D& aVector)
+constexpr QQuaternion::QQuaternion(float aScalar, const QVector3D &aVector) noexcept
     : wp(aScalar), xp(aVector.x()), yp(aVector.y()), zp(aVector.z()) {}
 
-inline void QQuaternion::setVector(const QVector3D& aVector)
+constexpr void QQuaternion::setVector(const QVector3D &aVector) noexcept
 {
     xp = aVector.x();
     yp = aVector.y();
     zp = aVector.z();
 }
 
-inline QVector3D QQuaternion::vector() const
+constexpr QVector3D QQuaternion::vector() const noexcept
 {
     return QVector3D(xp, yp, zp);
 }
@@ -325,7 +326,7 @@ inline QQuaternion QQuaternion::fromEulerAngles(const QVector3D &eulerAngles)
 
 #endif
 
-inline void QQuaternion::setVector(float aX, float aY, float aZ)
+constexpr void QQuaternion::setVector(float aX, float aY, float aZ) noexcept
 {
     xp = aX;
     yp = aY;
@@ -334,10 +335,10 @@ inline void QQuaternion::setVector(float aX, float aY, float aZ)
 
 #ifndef QT_NO_VECTOR4D
 
-inline QQuaternion::QQuaternion(const QVector4D& aVector)
+constexpr QQuaternion::QQuaternion(const QVector4D &aVector) noexcept
     : wp(aVector.w()), xp(aVector.x()), yp(aVector.y()), zp(aVector.z()) {}
 
-inline QVector4D QQuaternion::toVector4D() const
+constexpr QVector4D QQuaternion::toVector4D() const noexcept
 {
     return QVector4D(xp, yp, zp, wp);
 }