For Valgrind, zero out alignment bytes of 24-bit bitmap, too

...caused false warnings in CppunitTest_sw_filters_test testing
sw/qa/core/exportdata/html/pass/cp1000068.odt

Change-Id: I48943d5d4999e1b8c9a7ab50e39e65b2171b1b94

1 files changed, 7 insertions, 2 deletions

diff --git a/vcl/source/gdi/dibtools.cxx b/vcl/source/gdi/dibtools.cxx
index cf3f68660513..8814965eee89 100644
--- a/vcl/source/gdi/dibtools.cxx
+++ b/vcl/source/gdi/dibtools.cxx
@@ -1310,10 +1310,15 @@ bool ImplWriteDIBBits(SvStream& rOStm, BitmapReadAccess& rAcc, BitmapReadAccess*
                 }
                 break;
 
+                case 24:
+                {
+                    //valgrind, zero out the trailing unused alignment bytes
+                    size_t nUnusedBytes = nAlignedWidth - nWidth * 3;
+                    memset(pBuf.get() + nAlignedWidth - nUnusedBytes, 0, nUnusedBytes);
+                }
+                SAL_FALLTHROUGH;
                 // #i59239# fallback to 24 bit format, if bitcount is non-default
                 default:
-                    // FALLTHROUGH intended
-                case 24:
                 {
                     BitmapColor aPixelColor;
                     const bool bWriteAlpha(32 == nBitCount && pAccAlpha);