tdf#135500: always use transparent and clear content vdev in impBufferDevice

This removes the only place that hadn't used transparent impBufferDevice
yet - in VclProcessor2D::RenderMaskPrimitive2DPixel. Not clearing the vdev
made it draw on whatever garbage was left there from previous paints when
the buffer was taken from maFreeBuffers in VDevBuffer::alloc, so since this
was also the only place left that didn't clear the buffer explicitly, this
makes the clear unconditional in impBufferDevice ctor.

Also this makes sure to clear proper rectangle in VDevBuffer::alloc, and to
clear mpAlphaVDev in OutputDevice::Erase.

Change-Id: I7c1c0cc510a92628f19020b3faf0c0cd81f5a599
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/100674
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/vcl/source/outdev/wallpaper.cxx b/vcl/source/outdev/wallpaper.cxx
index ae3687d79f35..594fdbe05c9b 100644
--- a/vcl/source/outdev/wallpaper.cxx
+++ b/vcl/source/outdev/wallpaper.cxx
@@ -119,6 +119,19 @@ void OutputDevice::Erase()
         mpAlphaVDev->Erase();
 }
 
+void OutputDevice::Erase(const tools::Rectangle& rRect)
+{
+    const RasterOp eRasterOp = GetRasterOp();
+    if ( eRasterOp != RasterOp::OverPaint )
+        SetRasterOp( RasterOp::OverPaint );
+    DrawWallpaper(rRect, GetBackground());
+    if ( eRasterOp != RasterOp::OverPaint )
+        SetRasterOp( eRasterOp );
+
+    if (mpAlphaVDev)
+        mpAlphaVDev->Erase(rRect);
+}
+
 void OutputDevice::DrawBitmapWallpaper( long nX, long nY,
                                             long nWidth, long nHeight,
                                             const Wallpaper& rWallpaper )