QSize/QSizeF: add const versions of scale()/transpose()

Non-mutating functions can (potentially) be constexpr.
On top of that, they often make for more readable code.

Change-Id: I3547327cf5a7162737353a864a1025d0d02ccc2f
Reviewed-by: Gunnar Sletta <gunnar.sletta@nokia.com>
Reviewed-by: David Faure <faure@kde.org>

2 files changed, 85 insertions, 18 deletions

diff --git a/src/corelib/tools/qsize.cpp b/src/corelib/tools/qsize.cpp
index d5e6f18326..4c94f899e7 100644
--- a/src/corelib/tools/qsize.cpp
+++ b/src/corelib/tools/qsize.cpp
@@ -160,7 +160,7 @@ QT_BEGIN_NAMESPACE
 /*!
     Swaps the width and height values.
 
-    \sa setWidth(), setHeight()
+    \sa setWidth(), setHeight(), transposed()
 */
 
 void QSize::transpose()
@@ -171,6 +171,15 @@ void QSize::transpose()
 }
 
 /*!
+  \fn QSize QSize::transposed() const
+  \since 5.0
+
+  Returns a QSize with width and height swapped.
+
+  \sa transpose()
+*/
+
+/*!
   \fn void QSize::scale(int width, int height, Qt::AspectRatioMode mode)
 
     Scales the size to a rectangle with the given \a width and \a
@@ -187,7 +196,7 @@ void QSize::transpose()
     Example:
     \snippet doc/src/snippets/code/src_corelib_tools_qsize.cpp 0
 
-    \sa setWidth(), setHeight()
+    \sa setWidth(), setHeight(), scaled()
 */
 
 /*!
@@ -197,11 +206,25 @@ void QSize::transpose()
     Scales the size to a rectangle with the given \a size, according to
     the specified \a mode.
 */
-void QSize::scale(const QSize &s, Qt::AspectRatioMode mode)
+
+/*!
+    \fn QSize QSize::scaled(int width, int height, Qt::AspectRatioMode mode) const
+    \since 5.0
+
+    Return a size scaled to a rectangle with the given \a width and \a
+    height, according to the specified \a mode.
+
+    \sa scale()
+*/
+
+/*!
+  \overload
+  \since 5.0
+*/
+QSize QSize::scaled(const QSize &s, Qt::AspectRatioMode mode) const
 {
     if (mode == Qt::IgnoreAspectRatio || wd == 0 || ht == 0) {
-        wd = s.wd;
-        ht = s.ht;
+        return s;
     } else {
         bool useHeight;
         qint64 rw = qint64(s.ht) * qint64(wd) / qint64(ht);
@@ -213,11 +236,10 @@ void QSize::scale(const QSize &s, Qt::AspectRatioMode mode)
         }
 
         if (useHeight) {
-            wd = rw;
-            ht = s.ht;
+            return QSize(rw, s.ht);
         } else {
-            ht = qint32(qint64(s.wd) * qint64(ht) / qint64(wd));
-            wd = s.wd;
+            return QSize(s.wd,
+                         qint32(qint64(s.wd) * qint64(ht) / qint64(wd)));
         }
     }
 }
@@ -566,7 +588,7 @@ QDebug operator<<(QDebug dbg, const QSize &s) {
 /*!
     Swaps the width and height values.
 
-    \sa setWidth(), setHeight()
+    \sa setWidth(), setHeight(), transposed()
 */
 
 void QSizeF::transpose()
@@ -577,6 +599,15 @@ void QSizeF::transpose()
 }
 
 /*!
+    \fn QSizeF QSizeF::transposed() const
+    \since 5.0
+
+    Returns the size with width and height values swapped.
+
+    \sa transpose()
+*/
+
+/*!
   \fn void QSizeF::scale(qreal width, qreal height, Qt::AspectRatioMode mode)
 
     Scales the size to a rectangle with the given \a width and \a
@@ -593,7 +624,7 @@ void QSizeF::transpose()
     Example:
     \snippet doc/src/snippets/code/src_corelib_tools_qsize.cpp 5
 
-    \sa setWidth(), setHeight()
+    \sa setWidth(), setHeight(), scaled()
 */
 
 /*!
@@ -603,11 +634,25 @@ void QSizeF::transpose()
     Scales the size to a rectangle with the given \a size, according to
     the specified \a mode.
 */
-void QSizeF::scale(const QSizeF &s, Qt::AspectRatioMode mode)
+
+/*!
+    \fn QSizeF QSizeF::scaled(int width, int height, Qt::AspectRatioMode mode) const
+    \since 5.0
+
+    Returns a size scaled to a rectangle with the given \a width and
+    \a height, according to the specified \mode.
+
+    \sa scale()
+*/
+
+/*!
+  \overload
+  \since 5.0
+*/
+QSizeF QSizeF::scaled(const QSizeF &s, Qt::AspectRatioMode mode) const
 {
     if (mode == Qt::IgnoreAspectRatio || qIsNull(wd) || qIsNull(ht)) {
-        wd = s.wd;
-        ht = s.ht;
+        return s;
     } else {
         bool useHeight;
         qreal rw = s.ht * wd / ht;
@@ -619,11 +664,9 @@ void QSizeF::scale(const QSizeF &s, Qt::AspectRatioMode mode)
         }
 
         if (useHeight) {
-            wd = rw;
-            ht = s.ht;
+            return QSizeF(rw, s.ht);
         } else {
-            ht = s.wd * ht / wd;
-            wd = s.wd;
+            return QSizeF(s.wd, s.wd * ht / wd);
         }
     }
 }
diff --git a/src/corelib/tools/qsize.h b/src/corelib/tools/qsize.h
index 5400f76a3a..fece0ac943 100644
--- a/src/corelib/tools/qsize.h
+++ b/src/corelib/tools/qsize.h
@@ -64,9 +64,12 @@ public:
     void setWidth(int w);
     void setHeight(int h);
     void transpose();
+    QSize transposed() const;
 
     void scale(int w, int h, Qt::AspectRatioMode mode);
     void scale(const QSize &s, Qt::AspectRatioMode mode);
+    QSize scaled(int w, int h, Qt::AspectRatioMode mode) const;
+    QSize scaled(const QSize &s, Qt::AspectRatioMode mode) const;
 
     QSize expandedTo(const QSize &) const;
     QSize boundedTo(const QSize &) const;
@@ -134,9 +137,18 @@ inline void QSize::setWidth(int w)
 inline void QSize::setHeight(int h)
 { ht = h; }
 
+inline QSize QSize::transposed() const
+{ return QSize(ht, wd); }
+
 inline void QSize::scale(int w, int h, Qt::AspectRatioMode mode)
 { scale(QSize(w, h), mode); }
 
+inline void QSize::scale(const QSize &s, Qt::AspectRatioMode mode)
+{ *this = scaled(s, mode); }
+
+inline QSize QSize::scaled(int w, int h, Qt::AspectRatioMode mode) const
+{ return scaled(QSize(w, h), mode); }
+
 inline int &QSize::rwidth()
 { return wd; }
 
@@ -214,9 +226,12 @@ public:
     void setWidth(qreal w);
     void setHeight(qreal h);
     void transpose();
+    QSizeF transposed() const;
 
     void scale(qreal w, qreal h, Qt::AspectRatioMode mode);
     void scale(const QSizeF &s, Qt::AspectRatioMode mode);
+    QSizeF scaled(qreal w, qreal h, Qt::AspectRatioMode mode) const;
+    QSizeF scaled(const QSizeF &s, Qt::AspectRatioMode mode) const;
 
     QSizeF expandedTo(const QSizeF &) const;
     QSizeF boundedTo(const QSizeF &) const;
@@ -292,9 +307,18 @@ inline void QSizeF::setWidth(qreal w)
 inline void QSizeF::setHeight(qreal h)
 { ht = h; }
 
+inline QSizeF QSizeF::transposed() const
+{ return QSizeF(ht, wd); }
+
 inline void QSizeF::scale(qreal w, qreal h, Qt::AspectRatioMode mode)
 { scale(QSizeF(w, h), mode); }
 
+inline void QSizeF::scale(const QSizeF &s, Qt::AspectRatioMode mode)
+{ *this = scaled(s, mode); }
+
+inline QSizeF QSizeF::scaled(qreal w, qreal h, Qt::AspectRatioMode mode) const
+{ return scaled(QSizeF(w, h), mode); }
+
 inline qreal &QSizeF::rwidth()
 { return wd; }