From 941b55f5464b0e3f89f4e51dda75d2d1aa4becc4 Mon Sep 17 00:00:00 2001
From: narzoul <narzoul@users.noreply.github.com>
Date: Sun, 14 Feb 2016 20:26:15 +0100
Subject: [PATCH] Improved detection of scrolling events

---
 DDrawCompat/CompatGdiFunctions.cpp | 31 ++++++++++++++++++++++++++++++
 DDrawCompat/CompatGdiWinProc.cpp   | 11 ++++++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/DDrawCompat/CompatGdiFunctions.cpp b/DDrawCompat/CompatGdiFunctions.cpp
index 9c725f1..e7126a8 100644
--- a/DDrawCompat/CompatGdiFunctions.cpp
+++ b/DDrawCompat/CompatGdiFunctions.cpp
@@ -82,8 +82,37 @@ namespace
 	{
 		return &compatGdiFunc<OrigFuncPtr, origFunc, Result, Params...>;
 	}
+
+	BOOL WINAPI scrollWindow(
+		_In_       HWND hWnd,
+		_In_       int  XAmount,
+		_In_       int  YAmount,
+		_In_ const RECT *lpRect,
+		_In_ const RECT *lpClipRect)
+	{
+		InvalidateRect(hWnd, nullptr, TRUE);
+		return CALL_ORIG_GDI(ScrollWindow)(hWnd, XAmount, YAmount, lpRect, lpClipRect);
+	}
+
+	int WINAPI scrollWindowEx(
+		_In_        HWND   hWnd,
+		_In_        int    dx,
+		_In_        int    dy,
+		_In_  const RECT   *prcScroll,
+		_In_  const RECT   *prcClip,
+		_In_        HRGN   hrgnUpdate,
+		_Out_       LPRECT prcUpdate,
+		_In_        UINT   flags)
+	{
+		InvalidateRect(hWnd, nullptr, TRUE);
+		return CALL_ORIG_GDI(ScrollWindowEx)(hWnd, dx, dy, prcScroll, prcClip, hrgnUpdate, prcUpdate, flags);
+	}
 }
 
+#define HOOK_GDI_FUNCTION_CUSTOM(module, func, newFunc) \
+	CompatGdi::hookGdiFunction<decltype(&func), &func>( \
+		#module, #func, &newFunc);
+
 #define HOOK_GDI_FUNCTION(module, func) \
 	CompatGdi::hookGdiFunction<decltype(&func), &func>( \
 		#module, #func, getCompatGdiFuncPtr<decltype(&func), &func>(&func));
@@ -182,6 +211,8 @@ namespace CompatGdiFunctions
 
 		// Scroll bar functions
 		HOOK_GDI_FUNCTION(user32, ScrollDC);
+		HOOK_GDI_FUNCTION_CUSTOM(user32, ScrollWindow, scrollWindow);
+		HOOK_GDI_FUNCTION_CUSTOM(user32, ScrollWindowEx, scrollWindowEx);
 
 		DetourTransactionCommit();
 	}
diff --git a/DDrawCompat/CompatGdiWinProc.cpp b/DDrawCompat/CompatGdiWinProc.cpp
index 29535d5..dc0c2a8 100644
--- a/DDrawCompat/CompatGdiWinProc.cpp
+++ b/DDrawCompat/CompatGdiWinProc.cpp
@@ -48,6 +48,15 @@ namespace
 			{
 				updateScrolledWindow(ret->hwnd);
 			}
+			else if (WM_COMMAND == ret->message)
+			{
+				auto msgSource = LOWORD(ret->wParam);
+				auto notifCode = HIWORD(ret->wParam);
+				if (0 != msgSource && 1 != msgSource && (EN_HSCROLL == notifCode || EN_VSCROLL == notifCode))
+				{
+					updateScrolledWindow(reinterpret_cast<HWND>(ret->lParam));
+				}
+			}
 		}
 
 		return CallNextHookEx(nullptr, nCode, wParam, lParam);
@@ -83,7 +92,7 @@ namespace
 		if (HC_ACTION == nCode)
 		{
 			auto mhs = reinterpret_cast<MOUSEHOOKSTRUCT*>(lParam);
-			if (WM_MOUSEWHEEL == wParam)
+			if (WM_MOUSEWHEEL == wParam || WM_MOUSEHWHEEL == wParam)
 			{
 				updateScrolledWindow(mhs->hwnd);
 			}