QRect: add toRectF()

For symmetry with QRectF::toRect().

[ChangeLog][QtCore][QRect] Added toRectF().

Fixes: QTBUG-73160
Change-Id: If2bda64b8fe4bc113191dda927e9bb86ebcb4c69
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/tools/qrect.cpp

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2022 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -1232,6 +1232,18 @@ bool QRect::intersects(const QRect &r) const noexcept
     \since 6.0
 */
 
+/*!
+    \fn QRect::toRectF() const
+    \since 6.4
+
+    Returns this rectangle as a rectangle with floating point accuracy.
+
+    \note This function, like the QRectF(QRect) constructor, preserves the
+    size() of the rectangle, not its bottomRight() corner.
+
+    \sa QRectF::toRect()
+*/
+
 /*****************************************************************************
   QRect stream functions
  *****************************************************************************/
@@ -1480,7 +1492,10 @@ QDebug operator<<(QDebug dbg, const QRect &r)
 
     Constructs a QRectF rectangle from the given QRect \a rectangle.
 
-    \sa toRect()
+    \note This function, like QRect::toRectF(), preserves the size() of
+    \a rectangle, not its bottomRight() corner.
+
+    \sa toRect(), QRect::toRectF()
 */
 
 /*!
@@ -2334,7 +2349,7 @@ bool QRectF::intersects(const QRectF &r) const noexcept
     Returns a QRect based on the values of this rectangle.  Note that the
     coordinates in the returned rectangle are rounded to the nearest integer.
 
-    \sa QRectF(), toAlignedRect()
+    \sa QRectF(), toAlignedRect(), QRect::toRectF()
 */
 
 /*!

src/corelib/tools/qrect.h

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2022 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -55,6 +55,8 @@ struct CGRect;
 
 QT_BEGIN_NAMESPACE
 
+class QRectF;
+
 class Q_CORE_EXPORT QRect
 {
 public:
@@ -157,6 +159,7 @@ public:
 #if defined(Q_OS_DARWIN) || defined(Q_QDOC)
     [[nodiscard]] CGRect toCGRect() const noexcept;
 #endif
+    [[nodiscard]] constexpr inline QRectF toRectF() const noexcept;
 
 private:
     int x1;
@@ -863,6 +866,8 @@ inline QRectF QRectF::united(const QRectF &r) const noexcept
     return *this | r;
 }
 
+constexpr QRectF QRect::toRectF() const noexcept { return *this; }
+
 constexpr inline QRect QRectF::toRect() const noexcept
 {
     // This rounding is designed to minimize the maximum possible difference

tests/auto/corelib/tools/qrect/tst_qrect.cpp

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2022 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the test suite of the Qt Toolkit.
@@ -32,6 +32,7 @@
 #include <limits.h>
 #include <qdebug.h>
 
+#include <array>
 
 class tst_QRect : public QObject
 {
@@ -124,6 +125,9 @@ private slots:
     void margins();
     void marginsf();
 
+    void toRectF_data();
+    void toRectF();
+
     void translate_data();
     void translate();
 
@@ -3536,6 +3540,39 @@ void tst_QRect::marginsf()
     QCOMPARE(a, rectangle.marginsRemoved(margins));
 }
 
+void tst_QRect::toRectF_data()
+{
+    QTest::addColumn<QRect>("input");
+    QTest::addColumn<QRectF>("result");
+
+    auto row = [](int x1, int y1, int w, int h) {
+        // QRectF -> QRect conversion tries to maintain size(), not bottomRight(),
+        // so compare in (topLeft(), size()) space
+        QTest::addRow("((%d, %d) (%dx%d))", x1, y1, w, h)
+                << QRect({x1, y1}, QSize{w, h}) << QRectF(QPointF(x1, y1), QSizeF(w, h));
+    };
+    constexpr std::array samples = {-1, 0, 1};
+    for (int x1 : samples) {
+        for (int y1 : samples) {
+            for (int w : samples) {
+                for (int h : samples) {
+                    row(x1, y1, w, h);
+                }
+            }
+        }
+    }
+}
+
+void tst_QRect::toRectF()
+{
+    QFETCH(const QRect, input);
+    QFETCH(const QRectF, result);
+
+    QCOMPARE(result.toRect(), input); // consistency check
+    QCOMPARE(input.toRectF(), result);
+}
+
+
 void tst_QRect::translate_data()
 {
     QTest::addColumn<QRect>("r");