Fix to data detaching in OpenVG pixmap data

QImage::converToFormat(format) won't detach QImage if
format stays the same. Because of this, internal QImage
buffer of QVGPixmapData was not deep copied. Drawing
to QPixmap target modified the original QImage that was
used to create QPixmap and in some cases crashed because
paint engine referred to wrong target.

Task-number: QT-4407
Reviewed-by: Jason Barron
(cherry picked from commit b928bab9dde43cf3acace6dfae0ae6a4f6649650)

1 files changed, 10 insertions, 2 deletions

diff --git a/src/openvg/qpixmapdata_vg.cpp b/src/openvg/qpixmapdata_vg.cpp
index 3f768fd..d9f9aaa 100644
--- a/src/openvg/qpixmapdata_vg.cpp
+++ b/src/openvg/qpixmapdata_vg.cpp
@@ -200,6 +200,9 @@ bool QVGPixmapData::fromData(const uchar *buffer, uint len, const char *format,
     return !isNull();
 }
 
+/*!
+    out-of-place conversion (inPlace == false) will always detach()
+ */
 void QVGPixmapData::createPixmapForImage(QImage &image, Qt::ImageConversionFlags flags, bool inPlace)
 {
     if (image.size() == QSize(w, h))
@@ -216,11 +219,16 @@ void QVGPixmapData::createPixmapForImage(QImage &image, Qt::ImageConversionFlags
     else
         format = image.hasAlphaChannel() ? sourceFormat() : QImage::Format_RGB32;
 
-    if (inPlace && image.data_ptr()->convertInPlace(format, flags))
+    if (inPlace && image.data_ptr()->convertInPlace(format, flags)) {
         source = image;
-    else
+    } else {
         source = image.convertToFormat(format);
 
+        // convertToFormat won't detach the image if format stays the same.
+        if (image.format() == format)
+            source.detach();
+    }
+
     recreate = true;
 }