Add qHash(QMatrix) and qHash(QTransform)

QMatrix and QTransform can be compared for equality,
so qHash should be overloaded, too.

[ChangeLog][QtCore][QMatrix] Added qHash(QMatrix).
[ChangeLog][QtCore][QTransform] Added qHash(QTransform).

Change-Id: I1ce925ebe258c9d7e35b68e5ac5c3373f1460c58
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

src/gui/painting/qmatrix.cpp

@@ -31,9 +31,11 @@
 **
 ****************************************************************************/
 
+#include "qmatrix.h"
+
 #include "qdatastream.h"
 #include "qdebug.h"
-#include "qmatrix.h"
+#include "qhashfunctions.h"
 #include "qregion.h"
 #include "qpainterpath.h"
 #include "qpainterpath_p.h"
@@ -972,6 +974,26 @@ bool QMatrix::operator==(const QMatrix &m) const
            _dy == m._dy;
 }
 
+
+/*!
+    \since 5.6
+    \relates QMatrix
+
+    Returns the hash value for \a key, using
+    \a seed to seed the calculation.
+*/
+uint qHash(const QMatrix &key, uint seed) Q_DECL_NOTHROW
+{
+    QtPrivate::QHashCombine hash;
+    seed = hash(key.m11(), seed);
+    seed = hash(key.m12(), seed);
+    seed = hash(key.m21(), seed);
+    seed = hash(key.m22(), seed);
+    seed = hash(key.dx(),  seed);
+    seed = hash(key.dy(),  seed);
+    return seed;
+}
+
 /*!
     \fn bool QMatrix::operator!=(const QMatrix &matrix) const
 

src/gui/painting/qmatrix.h

@@ -126,6 +126,8 @@ private:
 };
 Q_DECLARE_TYPEINFO(QMatrix, Q_MOVABLE_TYPE);
 
+Q_GUI_EXPORT Q_DECL_CONST_FUNCTION uint qHash(const QMatrix &key, uint seed = 0) Q_DECL_NOTHROW;
+
 // mathematical semantics
 inline QPoint operator*(const QPoint &p, const QMatrix &m)
 { return m.map(p); }

src/gui/painting/qtransform.cpp

@@ -34,6 +34,7 @@
 
 #include "qdatastream.h"
 #include "qdebug.h"
+#include "qhashfunctions.h"
 #include "qmatrix.h"
 #include "qregion.h"
 #include "qpainterpath.h"
@@ -775,6 +776,29 @@ bool QTransform::operator==(const QTransform &o) const
            m_33 == o.m_33;
 }
 
+/*!
+    \since 5.6
+    \relates QTransform
+
+    Returns the hash value for \a key, using
+    \a seed to seed the calculation.
+*/
+uint qHash(const QTransform &key, uint seed) Q_DECL_NOTHROW
+{
+    QtPrivate::QHashCombine hash;
+    seed = hash(key.m11(), seed);
+    seed = hash(key.m12(), seed);
+    seed = hash(key.m21(), seed);
+    seed = hash(key.m22(), seed);
+    seed = hash(key.dx(),  seed);
+    seed = hash(key.dy(),  seed);
+    seed = hash(key.m13(), seed);
+    seed = hash(key.m23(), seed);
+    seed = hash(key.m33(), seed);
+    return seed;
+}
+
+
 /*!
     \fn bool QTransform::operator!=(const QTransform &matrix) const
     Returns \c true if this matrix is not equal to the given \a matrix,

src/gui/painting/qtransform.h

@@ -180,6 +180,8 @@ private:
 };
 Q_DECLARE_TYPEINFO(QTransform, Q_MOVABLE_TYPE);
 
+Q_GUI_EXPORT Q_DECL_CONST_FUNCTION uint qHash(const QTransform &key, uint seed = 0) Q_DECL_NOTHROW;
+
 /******* inlines *****/
 inline QTransform::TransformationType QTransform::inline_type() const
 {

tests/auto/gui/painting/qtransform/tst_qtransform.cpp

@@ -57,6 +57,7 @@ private slots:
     void mapRect();
     void assignments();
     void mapToPolygon();
+    void qhash();
     void translate();
     void scale();
     void matrix();
@@ -361,6 +362,22 @@ void tst_QTransform::mapToPolygon()
     QVERIFY(equal);
 }
 
+void tst_QTransform::qhash()
+{
+    QMatrix m1;
+    m1.shear(3.0, 2.0);
+    m1.rotate(44);
+
+    QMatrix m2 = m1;
+
+    QTransform t1(m1);
+    QTransform t2(m2);
+
+    // not really much to test here, so just the bare minimum:
+    QCOMPARE(qHash(m1), qHash(m2));
+    QCOMPARE(qHash(t1), qHash(t2));
+}
+
 
 void tst_QTransform::translate()
 {