2 files changed, 14 insertions, 2 deletions
diff --git a/src/platformsupport/fbconvenience/qfbbackingstore.cpp b/src/platformsupport/fbconvenience/qfbbackingstore.cpp
index e6b9e09a25..2cad3441e4 100644
--- a/src/platformsupport/fbconvenience/qfbbackingstore.cpp
+++ b/src/platformsupport/fbconvenience/qfbbackingstore.cpp
@@ -43,6 +43,7 @@
 
 #include <qpa/qplatformwindow.h>
 #include <QtGui/qscreen.h>
+#include <QtGui/qpainter.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -96,9 +97,17 @@ void QFbBackingStore::unlock()
     mImageMutex.unlock();
 }
 
-void QFbBackingStore::beginPaint(const QRegion &)
+void QFbBackingStore::beginPaint(const QRegion &region)
 {
     lock();
+
+    if (mImage.hasAlphaChannel()) {
+        QPainter p(&mImage);
+        p.setCompositionMode(QPainter::CompositionMode_Source);
+        const QVector<QRect> rects = region.rects();
+        for (QVector<QRect>::const_iterator it = rects.begin(); it != rects.end(); ++it)
+            p.fillRect(*it, Qt::transparent);
+    }
 }
 
 void QFbBackingStore::endPaint()
diff --git a/src/platformsupport/fbconvenience/qfbscreen.cpp b/src/platformsupport/fbconvenience/qfbscreen.cpp
index ee8183c896..01de2a59b2 100644
--- a/src/platformsupport/fbconvenience/qfbscreen.cpp
+++ b/src/platformsupport/fbconvenience/qfbscreen.cpp
@@ -237,6 +237,7 @@ QRegion QFbScreen::doRedraw()
 
     if (!mCompositePainter)
         mCompositePainter = new QPainter(mScreenImage);
+
     for (int rectIndex = 0; rectIndex < mRepaintRegion.rectCount(); rectIndex++) {
         QRegion rectRegion = rects[rectIndex];
 
@@ -254,7 +255,8 @@ QRegion QFbScreen::doRedraw()
             for (const QRect &rect : intersect) {
                 bool firstLayer = true;
                 if (layer == -1) {
-                    mCompositePainter->fillRect(rect, Qt::black);
+                    mCompositePainter->setCompositionMode(QPainter::CompositionMode_Source);
+                    mCompositePainter->fillRect(rect, mScreenImage->hasAlphaChannel() ? Qt::transparent : Qt::black);
                     firstLayer = false;
                     layer = mWindowStack.size() - 1;
                 }
@@ -287,6 +289,7 @@ QRegion QFbScreen::doRedraw()
 
     QRect cursorRect;
     if (mCursor && (mCursor->isDirty() || mRepaintRegion.intersects(mCursor->lastPainted()))) {
+        mCompositePainter->setCompositionMode(QPainter::CompositionMode_SourceOver);
         cursorRect = mCursor->drawCursor(*mCompositePainter);
         touchedRegion += cursorRect;
     }