From 8217ce0fef83a0aea3c658489c885d9bb69a3056 Mon Sep 17 00:00:00 2001
From: Jacek Caban <jacek@codeweavers.com>
Date: Thu, 2 Sep 2021 14:14:00 +0200
Subject: [PATCH] gdi32: Use NtGdiGetRandomRgn for GetClipRgn.

Signed-off-by: Jacek Caban <jacek@codeweavers.com>
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
---
 dlls/gdi32/clipping.c       | 36 ++++++++----------------------------
 dlls/gdi32/gdidc.c          |  8 ++++++++
 dlls/gdi32/tests/clipping.c |  7 ++++++-
 include/ntgdi.h             |  3 +++
 4 files changed, 25 insertions(+), 29 deletions(-)

diff --git a/dlls/gdi32/clipping.c b/dlls/gdi32/clipping.c
index 28a314b76b9..4f22e6f3cde 100644
--- a/dlls/gdi32/clipping.c
+++ b/dlls/gdi32/clipping.c
@@ -392,31 +392,6 @@ INT WINAPI NtGdiGetAppClipBox( HDC hdc, RECT *rect )
 }
 
 
-/***********************************************************************
- *           GetClipRgn  (GDI32.@)
- */
-INT WINAPI GetClipRgn( HDC hdc, HRGN hRgn )
-{
-    INT ret = -1;
-    DC * dc;
-    if ((dc = get_dc_ptr( hdc )))
-    {
-      if( dc->hClipRgn )
-      {
-          if (NtGdiCombineRgn( hRgn, dc->hClipRgn, 0, RGN_COPY ) != ERROR)
-          {
-              ret = 1;
-              if (dc->attr->layout & LAYOUT_RTL)
-                  mirror_region( hRgn, hRgn, dc->attr->vis_rect.right - dc->attr->vis_rect.left );
-          }
-      }
-      else ret = 0;
-      release_dc_ptr( dc );
-    }
-    return ret;
-}
-
-
 /***********************************************************************
  *           GetMetaRgn    (GDI32.@)
  */
@@ -460,11 +435,11 @@ INT WINAPI NtGdiGetRandomRgn( HDC hDC, HRGN hRgn, INT iCode )
 
     if (!dc) return -1;
 
-    switch (iCode)
+    switch (iCode & ~NTGDI_RGN_MIRROR_RTL)
     {
     case 1:
-        if (dc->hClipRgn) NtGdiCombineRgn( hRgn, dc->hClipRgn, 0, RGN_COPY );
-        else ret = 0;
+        if (!dc->hClipRgn) ret = 0;
+        else if (!NtGdiCombineRgn( hRgn, dc->hClipRgn, 0, RGN_COPY )) ret = -1;
         break;
     case 2:
         if (dc->hMetaRgn) NtGdiCombineRgn( hRgn, dc->hMetaRgn, 0, RGN_COPY );
@@ -496,6 +471,11 @@ INT WINAPI NtGdiGetRandomRgn( HDC hDC, HRGN hRgn, INT iCode )
         ret = -1;
         break;
     }
+
+    /* Wine extension */
+    if (ret > 0 && (iCode & NTGDI_RGN_MIRROR_RTL) && (dc->attr->layout & LAYOUT_RTL))
+        mirror_region( hRgn, hRgn, dc->attr->vis_rect.right - dc->attr->vis_rect.left );
+
     release_dc_ptr( dc );
     return ret;
 }
diff --git a/dlls/gdi32/gdidc.c b/dlls/gdi32/gdidc.c
index 0be21c75d58..6f534dce061 100644
--- a/dlls/gdi32/gdidc.c
+++ b/dlls/gdi32/gdidc.c
@@ -1633,6 +1633,14 @@ BOOL WINAPI SelectClipPath( HDC hdc, INT mode )
     return NtGdiSelectClipPath( hdc, mode );
 }
 
+/***********************************************************************
+ *           GetClipRgn  (GDI32.@)
+ */
+INT WINAPI GetClipRgn( HDC hdc, HRGN rgn )
+{
+    return NtGdiGetRandomRgn( hdc, rgn, NTGDI_RGN_MIRROR_RTL | 1 );
+}
+
 /***********************************************************************
  *           IntersectClipRect    (GDI32.@)
  */
diff --git a/dlls/gdi32/tests/clipping.c b/dlls/gdi32/tests/clipping.c
index 484430b0cb9..37a96de2bb4 100644
--- a/dlls/gdi32/tests/clipping.c
+++ b/dlls/gdi32/tests/clipping.c
@@ -42,6 +42,8 @@ static void test_GetRandomRgn(void)
 
     ret = GetRandomRgn(hdc, hrgn, 1);
     ok(ret == 0, "GetRandomRgn rets %d\n", ret);
+    ret = GetRandomRgn(hdc, NULL, 1);
+    ok(ret == 0, "GetRandomRgn rets %d\n", ret);
     ret = GetRandomRgn(hdc, hrgn, 2);
     ok(ret == 0, "GetRandomRgn rets %d\n", ret);
     ret = GetRandomRgn(hdc, hrgn, 3);
@@ -84,10 +86,13 @@ static void test_GetRandomRgn(void)
     IntersectClipRect(hdc, rc2.left, rc2.top, rc2.right, rc2.bottom);
 
     ret = GetRandomRgn(hdc, hrgn, 1);
-    ok(ret != 0, "GetRandomRgn rets %d\n", ret);
+    ok(ret > 0, "GetRandomRgn rets %d\n", ret);
     GetRgnBox(hrgn, &ret_rc);
     ok(EqualRect(&rc2, &ret_rc), "GetRandomRgn %s\n", wine_dbgstr_rect(&ret_rc));
 
+    ret = GetRandomRgn(hdc, NULL, 1);
+    ok(ret == -1, "GetRandomRgn rets %d\n", ret);
+
     ret = GetRandomRgn(hdc, hrgn, 2);
     ok(ret != 0, "GetRandomRgn rets %d\n", ret);
     GetRgnBox(hrgn, &ret_rc);
diff --git a/include/ntgdi.h b/include/ntgdi.h
index 00783975e18..061ed40779c 100644
--- a/include/ntgdi.h
+++ b/include/ntgdi.h
@@ -178,6 +178,9 @@ struct font_enum_entry
     NEWTEXTMETRICEXW tm;
 };
 
+/* flag for NtGdiGetRandomRgn to respect LAYOUT_RTL */
+#define NTGDI_RGN_MIRROR_RTL   0x80000000
+
 #endif /* __WINESRC__ */
 
 struct font_realization_info