[PATCH 4/5] win32u: Only reuse scaling target surface if it matches the monitor rect.

[Rémi Bernon]

From: Rémi Bernon

---
 dlls/win32u/dce.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/dlls/win32u/dce.c b/dlls/win32u/dce.c
index 2faf73f2f53..b7272b8bef8 100644
--- a/dlls/win32u/dce.c
+++ b/dlls/win32u/dce.c
@@ -274,10 +274,15 @@ void create_window_surface( HWND hwnd, BOOL create_layered, const RECT *surface_
     UINT dpi = get_dpi_for_window( hwnd );
     RECT monitor_rect;

-    if ((driver_surface = get_driver_window_surface( *window_surface, monitor_dpi )))
-        window_surface_add_ref( driver_surface );

monitor_rect = get_surface_rect( map_dpi_rect( *surface_rect, dpi, monitor_dpi ) );
+    if ((driver_surface = get_driver_window_surface( *window_surface, monitor_dpi )))
+    {
+        /* reuse the underlying driver surface only if it also matches the target monitor rect */
+        if (EqualRect( &driver_surface->rect, &monitor_rect )) window_surface_add_ref( driver_surface );
+        else window_surface_add_ref( (driver_surface = &dummy_surface) );
+    }
+
     if (!user_driver->pCreateWindowSurface( hwnd, create_layered, &monitor_rect, &driver_surface ))
     {
         if (driver_surface) window_surface_release( driver_surface );