[PATCH v4 5/9] win32u: Clip PAINTSTRUCT.rcPaint to the window client area.

[Dmitry Timoshkov]

From: Dmitry Timoshkov

Signed-off-by: Dmitry Timoshkov 
---
 dlls/win32u/dce.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/dlls/win32u/dce.c b/dlls/win32u/dce.c
index cfa3510c60b..727b5c31417 100644
--- a/dlls/win32u/dce.c
+++ b/dlls/win32u/dce.c
@@ -1157,6 +1157,8 @@ static BOOL send_erase( HWND hwnd, UINT flags, HRGN client_rgn,
     HDC hdc = 0;
     RECT dummy;

+    TRACE( "hwnd %p, flags %08x, client_rgn %p\n", hwnd, flags, client_rgn );
+
     if (!clip_rect) clip_rect = &dummy;
     if (hdc_ret || (flags & UPDATE_ERASE))
     {
@@ -1167,6 +1169,13 @@ static BOOL send_erase( HWND hwnd, UINT flags, HRGN client_rgn,
         {
             INT type = NtGdiGetAppClipBox( hdc, clip_rect );

+            if (get_class_long( hwnd, GCL_STYLE, FALSE ) & CS_PARENTDC)
+            {
+                RECT client_rect;
+                get_client_rect( hwnd, &client_rect, get_thread_dpi() );
+                intersect_rect( clip_rect, clip_rect, &client_rect );
+            }
+
             if (flags & UPDATE_ERASE)
             {
                 /* don't erase if the clip box is empty */