Optimized sub-rect copying / painting of QPixmaps.

Prevented downloading of the whole XImage by introducing new
QPixmapData::toImage() overload taking a sub-rect. Also avoid an
additional copy by simply taking ownership of the XImage data when
the XImage format matches the QImage format.

Reviewed-by: Trond

1 files changed, 9 insertions, 1 deletions

diff --git a/src/gui/image/qpixmapdata.cpp b/src/gui/image/qpixmapdata.cpp
index 31ca909661..345e3cf6e1 100644
--- a/src/gui/image/qpixmapdata.cpp
+++ b/src/gui/image/qpixmapdata.cpp
@@ -146,7 +146,7 @@ bool QPixmapData::fromData(const uchar *buf, uint len, const char *format, Qt::I
 
 void QPixmapData::copy(const QPixmapData *data, const QRect &rect)
 {
-    fromImage(data->toImage().copy(rect), Qt::NoOpaqueDetection);
+    fromImage(data->toImage(rect), Qt::NoOpaqueDetection);
 }
 
 bool QPixmapData::scroll(int dx, int dy, const QRect &rect)
@@ -255,6 +255,14 @@ void QPixmapData::setSerialNumber(int serNo)
     ser_no = serNo;
 }
 
+QImage QPixmapData::toImage(const QRect &rect) const
+{
+    if (rect.contains(QRect(0, 0, w, h)))
+        return toImage();
+    else
+        return toImage().copy(rect);
+}
+
 QImage* QPixmapData::buffer()
 {
     return 0;