RValue ref version of QPixmap::fromImage()

When converting from a temporary image we can use inplace conversion
since we don't have to worry about changes made to the original.

This should give a speedup in several places where QPixmaps are made
from
the return values of methods returning QImages.

Change-Id: I1835bcf3fc061c4dbbb3d0507ec84178dc49b29b
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/gui/image/qpixmap.cpp

@@ -1616,6 +1616,28 @@ QPixmap QPixmap::fromImage(const QImage &image, Qt::ImageConversionFlags flags)
     return QPixmap(data.take());
 }
 
+/*!
+    \fn QPixmap QPixmap::fromImage(QImage &&image, Qt::ImageConversionFlags flags)
+    \since 5.3
+    \overload
+
+    Converts the given \a image to a pixmap without copying if possible.
+*/
+
+
+/*!
+    \internal
+*/
+QPixmap QPixmap::fromImageInPlace(QImage &image, Qt::ImageConversionFlags flags)
+{
+    if (image.isNull())
+        return QPixmap();
+
+    QScopedPointer<QPlatformPixmap> data(QGuiApplicationPrivate::platformIntegration()->createPlatformPixmap(QPlatformPixmap::PixmapType));
+    data->fromImageInPlace(image, flags);
+    return QPixmap(data.take());
+}
+
 /*!
     \fn QPixmap QPixmap::fromImageReader(QImageReader *imageReader, Qt::ImageConversionFlags flags)
 

src/gui/image/qpixmap.h

@@ -131,6 +131,12 @@ public:
     QImage toImage() const;
     static QPixmap fromImage(const QImage &image, Qt::ImageConversionFlags flags = Qt::AutoColor);
     static QPixmap fromImageReader(QImageReader *imageReader, Qt::ImageConversionFlags flags = Qt::AutoColor);
+#ifdef Q_COMPILER_RVALUE_REFS
+    static QPixmap fromImage(QImage &&image, Qt::ImageConversionFlags flags = Qt::AutoColor)
+    {
+        return fromImageInPlace(image, flags);
+    }
+#endif
 
     bool load(const QString& fileName, const char *format = 0, Qt::ImageConversionFlags flags = Qt::AutoColor);
     bool loadFromData(const uchar *buf, uint len, const char* format = 0, Qt::ImageConversionFlags flags = Qt::AutoColor);
@@ -167,6 +173,7 @@ public:
 
 protected:
     int metric(PaintDeviceMetric) const;
+    static QPixmap fromImageInPlace(QImage &image, Qt::ImageConversionFlags flags = Qt::AutoColor);
 
 private:
     QExplicitlySharedDataPointer<QPlatformPixmap> data;

src/gui/image/qpixmap_raster.cpp

@@ -135,11 +135,16 @@ bool QRasterPlatformPixmap::fromData(const uchar *buffer, uint len, const char *
 void QRasterPlatformPixmap::fromImage(const QImage &sourceImage,
                                   Qt::ImageConversionFlags flags)
 {
-    Q_UNUSED(flags);
     QImage image = sourceImage;
     createPixmapForImage(image, flags, /* inplace = */false);
 }
 
+void QRasterPlatformPixmap::fromImageInPlace(QImage &sourceImage,
+                                             Qt::ImageConversionFlags flags)
+{
+    createPixmapForImage(sourceImage, flags, /* inplace = */true);
+}
+
 void QRasterPlatformPixmap::fromImageReader(QImageReader *imageReader,
                                         Qt::ImageConversionFlags flags)
 {

src/gui/image/qpixmap_raster_p.h

@@ -69,6 +69,7 @@ public:
     void resize(int width, int height);
     bool fromData(const uchar *buffer, uint len, const char *format, Qt::ImageConversionFlags flags);
     void fromImage(const QImage &image, Qt::ImageConversionFlags flags);
+    void fromImageInPlace(QImage &image, Qt::ImageConversionFlags flags);
     void fromImageReader(QImageReader *imageReader, Qt::ImageConversionFlags flags);
 
     void copy(const QPlatformPixmap *data, const QRect &rect);

src/gui/image/qplatformpixmap.h

@@ -79,6 +79,12 @@ public:
     virtual void resize(int width, int height) = 0;
     virtual void fromImage(const QImage &image,
                            Qt::ImageConversionFlags flags) = 0;
+    virtual void fromImageInPlace(QImage &image,
+                                  Qt::ImageConversionFlags flags)
+    {
+        fromImage(image, flags);
+    }
+
     virtual void fromImageReader(QImageReader *imageReader,
                                  Qt::ImageConversionFlags flags);