[reactos] 01/02: [WIN32K] Fix off-by-one errors

[Jérôme Gardou]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=068687e0fde0f417ed8a8…

commit 068687e0fde0f417ed8a81c44a0009de721da68a
Author:     Jérôme Gardou <jerome.gardou(a)reactos.org>
AuthorDate: Wed Mar 31 09:59:44 2021 +0200
Commit:     Jérôme Gardou <zefklop(a)users.noreply.github.com>
CommitDate: Wed Mar 31 16:39:57 2021 +0200

    [WIN32K] Fix off-by-one errors
    
    Spotted by Doug Lyons
    CORE-17520
---
 win32ss/gdi/dib/dib1bpp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/win32ss/gdi/dib/dib1bpp.c b/win32ss/gdi/dib/dib1bpp.c
index 6a90282808d..c1b33ad4182 100644
--- a/win32ss/gdi/dib/dib1bpp.c
+++ b/win32ss/gdi/dib/dib1bpp.c
@@ -78,7 +78,7 @@ DIB_1BPP_BitBltSrcCopy_From1BPP (
     {
         LONG yDst = DestRect->top + Height;
         LONG ySrc = bTopToBottom ?
-            SourcePoint->y + RECTL_lGetHeight(DestRect) - Height
+            SourcePoint->y + RECTL_lGetHeight(DestRect) - Height - 1
             : SourcePoint->y + Height;
         LONG Width = RECTL_lGetWidth(DestRect);
 
@@ -86,7 +86,7 @@ DIB_1BPP_BitBltSrcCopy_From1BPP (
         {
             LONG xDst = DestRect->left + Width;
             LONG xSrc = bLeftToRight ?
-                SourcePoint->x + RECTL_lGetWidth(DestRect) - Width
+                SourcePoint->x + RECTL_lGetWidth(DestRect) - Width - 1
                 : SourcePoint->x + Width;
             ULONG PixelPut = DIB_1BPP_GetPixel(SourceSurf, xSrc, ySrc);
             if (XorBit)