Resolves: tdf#92982 vcl rendercontext: handle buffered paint of vcl::Cursor

Instead of painting on the vcl::Window directly, take a
PaintBufferGuard, and use the vcl::RenderContext of it, that may be
either the vcl::Window or the toplevel frame's buffer.

Trigger the paint of the buffer by informing the guard what area was
painted. In case of direct painting, both the ctor and the dtor of the
guard is a NOP.

This means that finally we can also assert Invert() calls on the output
device, so that direct paint can't happen when double-buffering.

Change-Id: I0322563369dc63b3c49061cbe7c4a911cb13a2e2

1 files changed, 2 insertions, 0 deletions

diff --git a/vcl/source/outdev/rect.cxx b/vcl/source/outdev/rect.cxx
index d786649c0cb4..e8ecf440de50 100644
--- a/vcl/source/outdev/rect.cxx
+++ b/vcl/source/outdev/rect.cxx
@@ -131,6 +131,7 @@ void OutputDevice::DrawRect( const Rectangle& rRect,
 
 void OutputDevice::Invert( const Rectangle& rRect, InvertFlags nFlags )
 {
+    assert(!is_double_buffered_window());
     if ( !IsDeviceOutputNecessary() )
         return;
 
@@ -163,6 +164,7 @@ void OutputDevice::Invert( const Rectangle& rRect, InvertFlags nFlags )
 
 void OutputDevice::Invert( const Polygon& rPoly, InvertFlags nFlags )
 {
+    assert(!is_double_buffered_window());
     if ( !IsDeviceOutputNecessary() )
         return;