From 527c11cf4d123b2c6a4bcb9f50774922dc3edbc0 Mon Sep 17 00:00:00 2001
From: James Tabor <james.tabor@reactos.org>
Date: Thu, 22 Dec 2016 16:39:33 +0000
Subject: [PATCH] [Win32SS|RTL] - Fix clipping for Draw Text. Inspired by
 Katayama Hirofumi MZ patch and ComCtl32/RichEd20/UxThmems. See CORE-2201.

svn path=/trunk/; revision=73475
---
 reactos/win32ss/user/rtl/text.c | 58 ++++++++++++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/reactos/win32ss/user/rtl/text.c b/reactos/win32ss/user/rtl/text.c
index 00a38e09030..f278bffec4e 100644
--- a/reactos/win32ss/user/rtl/text.c
+++ b/reactos/win32ss/user/rtl/text.c
@@ -986,6 +986,9 @@ INT WINAPI DrawTextExWorker( HDC hdc,
     int prefix_offset;
     ellipsis_data ellip;
     BOOL invert_y=FALSE;
+
+    HRGN    hrgn = 0;
+
 #ifdef _WIN32K_
     TRACE("%S, %d, %08x\n", str, count, flags);
 #else
@@ -1072,7 +1075,40 @@ INT WINAPI DrawTextExWorker( HDC hdc,
     }
 
     if (flags & DT_CALCRECT) flags |= DT_NOCLIP;
-
+#ifndef _WIN32K_ ///// Fix CORE-2201.
+    if (!(flags & DT_NOCLIP) )
+    {
+       int hasClip;
+       hrgn = CreateRectRgn(0,0,0,0);
+       if (hrgn)
+       {
+          hasClip = GetClipRgn(hdc, hrgn);
+          // If the region to be retrieved is NULL, the return value is 0.
+          if (hasClip != 1)
+          {
+             DeleteObject(hrgn);
+             hrgn = NULL;
+          }
+          IntersectClipRect(hdc, rect->left, rect->top, rect->right, rect->bottom);
+       }
+    }
+#else
+    if (!(flags & DT_NOCLIP) )
+    {
+       int hasClip;
+       hrgn = NtGdiCreateRectRgn(0,0,0,0);
+       if (hrgn)
+       {
+          hasClip = NtGdiGetRandomRgn(hdc, hrgn, CLIPRGN);
+          if (hasClip != 1)
+          {
+             GreDeleteObject(hrgn);
+             hrgn = NULL;
+          }
+          NtGdiIntersectClipRect(hdc, rect->left, rect->top, rect->right, rect->bottom);
+       }
+    }
+#endif /////
     if (flags & DT_MODIFYSTRING)
     {
         size_retstr = (count + 4) * sizeof (WCHAR);
@@ -1226,6 +1262,26 @@ INT WINAPI DrawTextExWorker( HDC hdc,
     }
     while (strPtr && !last_line);
 
+#ifndef _WIN32K_
+    if (!(flags & DT_NOCLIP) )
+    {
+       SelectClipRgn(hdc, hrgn);
+       if (hrgn)
+       {
+          DeleteObject(hrgn);
+       }
+    }
+#else
+    if (!(flags & DT_NOCLIP) )
+    {
+       NtGdiExtSelectClipRgn(hdc, hrgn, RGN_COPY);
+       if (hrgn)
+       {
+          GreDeleteObject(hrgn);
+       }
+    }
+#endif
+
     if (flags & DT_CALCRECT)
     {
 	rect->right = rect->left + max_width;