Ref qualified version of QImage::convertToFormat

Add ref qualified versions of QImage::convertToFormat, so that a
temporary QImage can be converted in-place to a format of equal depth.

[ChangeLog][QtGui][QImage]Added rvalue qualified convertToFormat method
for in-place conversion

Change-Id: I2eed5ffd63f5aea4ffa1147bf7607b02a49d9c5d
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>

src/gui/image/qimage.cpp

@@ -1862,6 +1862,8 @@ QImage::Format QImage::format() const
 }
 
 /*!
+    \fn QImage QImage::convertToFormat(Format format, Qt::ImageConversionFlags flags) const
+
     Returns a copy of the image in the given \a format.
 
     The specified image conversion \a flags control how the image data
@@ -1869,7 +1871,11 @@ QImage::Format QImage::format() const
 
     \sa {Image Formats}
 */
-QImage QImage::convertToFormat(Format format, Qt::ImageConversionFlags flags) const
+
+/*!
+    \internal
+*/
+QImage QImage::convertToFormat_helper(Format format, Qt::ImageConversionFlags flags) const
 {
     if (!d || d->format == format)
         return *this;
@@ -1902,6 +1908,14 @@ QImage QImage::convertToFormat(Format format, Qt::ImageConversionFlags flags) co
     return convertToFormat(Format_ARGB32, flags).convertToFormat(format, flags);
 }
 
+/*!
+    \internal
+*/
+bool QImage::convertToFormat_inplace(Format format, Qt::ImageConversionFlags flags)
+{
+    return d && d->convertInPlace(format, flags);
+}
+
 static inline int pixel_distance(QRgb p1, QRgb p2) {
     int r1 = qRed(p1);
     int g1 = qGreen(p1);

src/gui/image/qimage.h

@@ -172,7 +172,19 @@ public:
 
     Format format() const;
 
+#if defined(Q_COMPILER_REF_QUALIFIERS) && !defined(QT_COMPILING_QIMAGE_COMPAT_CPP)
+    QImage convertToFormat(Format f, Qt::ImageConversionFlags flags = Qt::AutoColor) const & Q_REQUIRED_RESULT
+    { return convertToFormat_helper(f, flags); }
+    QImage convertToFormat(Format f, Qt::ImageConversionFlags flags = Qt::AutoColor) && Q_REQUIRED_RESULT
+    {
+        if (convertToFormat_inplace(f, flags))
+            return std::move(*this);
+        else
+            return convertToFormat_helper(f, flags);
+    }
+#else
     QImage convertToFormat(Format f, Qt::ImageConversionFlags flags = Qt::AutoColor) const Q_REQUIRED_RESULT;
+#endif
     QImage convertToFormat(Format f, const QVector<QRgb> &colorTable, Qt::ImageConversionFlags flags = Qt::AutoColor) const Q_REQUIRED_RESULT;
 
     int width() const;
@@ -313,6 +325,8 @@ protected:
     QImage rgbSwapped_helper() const;
     void mirrored_inplace(bool horizontal, bool vertical);
     void rgbSwapped_inplace();
+    QImage convertToFormat_helper(Format format, Qt::ImageConversionFlags flags) const;
+    bool convertToFormat_inplace(Format format, Qt::ImageConversionFlags flags);
 
 private:
     friend class QWSOnScreenSurface;

src/gui/image/qimage_compat.cpp

@@ -49,6 +49,12 @@
 QT_BEGIN_NAMESPACE
 
 // These implementations must be the same as the inline versions in qimage.h
+
+QImage QImage::convertToFormat(Format f, Qt::ImageConversionFlags flags) const
+{
+    return convertToFormat_helper(f, flags);
+}
+
 QImage QImage::mirrored(bool horizontally, bool vertically) const
 {
     return mirrored_helper(horizontally, vertically);

tests/auto/gui/image/qimage/tst_qimage.cpp

@@ -158,7 +158,10 @@ private slots:
     void inplaceMirrored_data();
     void inplaceMirrored();
 
-    void inplaceDoubleConversion();
+    void inplaceRgbMirrored();
+
+    void inplaceConversion_data();
+    void inplaceConversion();
 
     void deepCopyWhenPaintingActive();
     void scaled_QTBUG19157();
@@ -2342,7 +2345,7 @@ void tst_QImage::inplaceMirrored()
 #endif
 }
 
-void tst_QImage::inplaceDoubleConversion()
+void tst_QImage::inplaceRgbMirrored()
 {
 #if defined(Q_COMPILER_REF_QUALIFIERS)
     QImage image1(32, 32, QImage::Format_ARGB32);
@@ -2357,6 +2360,47 @@ void tst_QImage::inplaceDoubleConversion()
 #endif
 }
 
+void tst_QImage::inplaceConversion_data()
+{
+    QTest::addColumn<QImage::Format>("format");
+    QTest::addColumn<QImage::Format>("dest_format");
+
+    QTest::newRow("Format_ARGB32 -> Format_RGBA8888") << QImage::Format_ARGB32 << QImage::Format_RGBA8888;
+    QTest::newRow("Format_RGB888 -> Format_ARGB6666_Premultiplied") << QImage::Format_RGB888 << QImage::Format_ARGB6666_Premultiplied;
+    QTest::newRow("Format_RGB16 -> Format_RGB555") << QImage::Format_RGB16 << QImage::Format_RGB555;
+    QTest::newRow("Format_RGB666 -> Format_RGB888") << QImage::Format_RGB666 << QImage::Format_RGB888;
+    QTest::newRow("Format_ARGB8565_Premultiplied, Format_ARGB8555_Premultiplied") << QImage::Format_ARGB8565_Premultiplied << QImage::Format_ARGB8555_Premultiplied;
+    QTest::newRow("Format_ARGB4444_Premultiplied, Format_RGB444") << QImage::Format_ARGB4444_Premultiplied << QImage::Format_RGB444;
+}
+
+void tst_QImage::inplaceConversion()
+{
+    // Test that conversions between RGB formats of the same bitwidth can be done inplace.
+#if defined(Q_COMPILER_REF_QUALIFIERS)
+    QFETCH(QImage::Format, format);
+    QFETCH(QImage::Format, dest_format);
+
+    QImage image(16, 16, format);
+
+    for (int i = 0; i < image.height(); ++i)
+        for (int j = 0; j < image.width(); ++j)
+            image.setPixel(j, i, qRgb(j*16, i*16, 0));
+
+    const uchar* originalPtr = image.constScanLine(0);
+
+    QImage imageConverted = std::move(image).convertToFormat(dest_format);
+    for (int i = 0; i < imageConverted.height(); ++i) {
+        for (int j = 0; j < imageConverted.width(); ++j) {
+            QRgb convertedColor = imageConverted.pixel(j,i);
+            QCOMPARE(qRed(convertedColor) & 0xF0, j * 16);
+            QCOMPARE(qGreen(convertedColor) & 0xF0, i * 16);
+        }
+    }
+
+    QCOMPARE(imageConverted.constScanLine(0), originalPtr);
+#endif
+}
+
 void tst_QImage::deepCopyWhenPaintingActive()
 {
     QImage image(64, 64, QImage::Format_ARGB32_Premultiplied);