Get transparency working by clearing the window surface.

This is duplicated code from the raster paint engine's beginPaint()
function. For translucent windows the previous contents must be cleared
from the backing store before the new content is painted. This class
should probably be re-written as a subclass of the raster version. The
reason we cannot use that implementation directly is because we cannot
use QNativeImage because it doesn't provide anywhere we can do locking.

1 files changed, 22 insertions, 1 deletions

diff --git a/src/gui/painting/qwindowsurface_s60.cpp b/src/gui/painting/qwindowsurface_s60.cpp
index 50278ce..85190c2 100644
--- a/src/gui/painting/qwindowsurface_s60.cpp
+++ b/src/gui/painting/qwindowsurface_s60.cpp
@@ -15,6 +15,7 @@
 #include <private/qwidget_p.h>
 #include "qwindowsurface_s60_p.h"
 #include "qt_s60_p.h"
+#include "private/qdrawhelper_p.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -61,7 +62,7 @@ QS60WindowSurface::~QS60WindowSurface()
     delete d_ptr;
 }
 
-void QS60WindowSurface::beginPaint(const QRegion &)
+void QS60WindowSurface::beginPaint(const QRegion &rgn)
 {
     if(!d_ptr->bitmap)
         return;
@@ -69,6 +70,26 @@ void QS60WindowSurface::beginPaint(const QRegion &)
     Q_ASSERT(!QS60WindowSurfacePrivate::lockedSurface);
     QS60WindowSurfacePrivate::lockedSurface = this;
     lockBitmapHeap();
+
+    if (!qt_widget_private(window())->isOpaque) {
+        QRgb *data = reinterpret_cast<QRgb *>(d_ptr->device.bits());
+        const int row_stride = d_ptr->device.bytesPerLine() / 4;
+
+        const QVector<QRect> rects = rgn.rects();
+        for (QVector<QRect>::const_iterator it = rects.begin(); it != rects.end(); ++it) {
+            const int x_start = it->x();
+            const int width = it->width();
+
+            const int y_start = it->y();
+            const int height = it->height();
+
+            QRgb *row = data + row_stride * y_start;
+            for (int y = 0; y < height; ++y) {
+                qt_memfill(row + x_start, 0U, width);
+                row += row_stride;
+            }
+        }
+    }
 }
 
 void QS60WindowSurface::flush(QWidget *widget, const QRegion &region, const QPoint &)