wintab32: Use 64-bit math in ScaleForContext.

With some tablet configurations, the InExt value passed to ScaleForContext can be very large, leading to an integer overflow. Signed-off-by: John Chadwick <john@jchw.io> Signed-off-by: Alexandre Julliard <julliard@winehq.org>

wintab32: Use 64-bit math in ScaleForContext.
27afc0d3 · John Chadwick · Alexandre Julliard · a45dfea9 · 27afc0d3
Commit 27afc0d3 authored Nov 17, 2019 by John Chadwick Committed by Alexandre Julliard Nov 18, 2019
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context.c dlls/wintab32/context.c +2 -2

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--- a/dlls/wintab32/context.c
+++ b/dlls/wintab32/context.c
@@ -178,9 +178,9 @@ int TABLET_PostTabletMessage(LPOPENCONTEXT newcontext, UINT msg, WPARAM wParam,
 static inline DWORD ScaleForContext(DWORD In, LONG InOrg, LONG InExt, LONG OutOrg, LONG OutExt)
 {
    if (((InExt > 0 )&&(OutExt > 0)) || ((InExt<0) && (OutExt < 0)))
-        return ((In - InOrg) * abs(OutExt) / abs(InExt)) + OutOrg;
+        return MulDiv(In - InOrg, abs(OutExt), abs(InExt)) + OutOrg;
    else
-        return ((abs(InExt) - (In - InOrg))*abs(OutExt) / abs(InExt)) + OutOrg;
+        return MulDiv(abs(InExt) - (In - InOrg), abs(OutExt), abs(InExt)) + OutOrg;
 }

 LPOPENCONTEXT AddPacketToContextQueue(LPWTPACKET packet, HWND hwnd)