Fixed bug in X11 paint engine causing source pixmap depth to change.

Setting a pixmap brush when painting to a 32-bit target might cause the
source pixmap to be converted to 32-bit. We should detach the pixmap if
we need to convert it.

Reviewed-by: Trond

2 files changed, 20 insertions, 0 deletions

diff --git a/src/gui/painting/qpaintengine_x11.cpp b/src/gui/painting/qpaintengine_x11.cpp
index 4d2521a..59482c6 100644
--- a/src/gui/painting/qpaintengine_x11.cpp
+++ b/src/gui/painting/qpaintengine_x11.cpp
@@ -1402,6 +1402,7 @@ void QX11PaintEngine::updateBrush(const QBrush &brush, const QPointF &origin)
             mask |= GCTile;
 #ifndef QT_NO_XRENDER
             if (d->pdev_depth == 32 && d->brush_pm.depth() != 32) {
+                d->brush_pm.detach();
                 QX11PixmapData *brushData = static_cast<QX11PixmapData*>(d->brush_pm.data.data());
                 brushData->convertToARGB32();
             }
diff --git a/tests/auto/qpixmap/tst_qpixmap.cpp b/tests/auto/qpixmap/tst_qpixmap.cpp
index 2568b94..36c1518 100644
--- a/tests/auto/qpixmap/tst_qpixmap.cpp
+++ b/tests/auto/qpixmap/tst_qpixmap.cpp
@@ -166,6 +166,8 @@ private slots:
     void fromImage_crash();
 
     void fromData();
+
+    void preserveDepth();
 };
 
 static bool lenientCompare(const QPixmap &actual, const QPixmap &expected)
@@ -1448,6 +1450,23 @@ void tst_QPixmap::task_246446()
     QVERIFY(pm.mask().isNull());
 }
 
+void tst_QPixmap::preserveDepth()
+{
+    QPixmap target(64, 64);
+    target.fill(Qt::transparent);
+
+    QPixmap source(64, 64);
+    source.fill(Qt::white);
+
+    int depth = source.depth();
+
+    QPainter painter(&target);
+    painter.setBrush(source);
+    painter.drawRect(target.rect());
+    painter.end();
+
+    QCOMPARE(depth, source.depth());
+}
 
 QTEST_MAIN(tst_QPixmap)
 #include "tst_qpixmap.moc"