1 files changed, 14 insertions, 0 deletions
diff --git a/win32/PlatWin.h b/win32/PlatWin.h
index 893618b38..68098f9c7 100644
--- a/win32/PlatWin.h
+++ b/win32/PlatWin.h
@@ -49,6 +49,20 @@ int SystemMetricsForDpi(int nIndex, UINT dpi) noexcept;
 
 HCURSOR LoadReverseArrowCursor(UINT dpi) noexcept;
 
+class MouseWheelDelta {
+	int wheelDelta = 0;
+public:
+	bool Accumulate(WPARAM wParam) noexcept {
+		wheelDelta -= GET_WHEEL_DELTA_WPARAM(wParam);
+		return std::abs(wheelDelta) >= WHEEL_DELTA;
+	}
+	int Actions() noexcept {
+		const int actions = wheelDelta / WHEEL_DELTA;
+		wheelDelta = wheelDelta % WHEEL_DELTA;
+		return actions;
+	}
+};
+
 #if defined(USE_D2D)
 extern bool LoadD2D();
 extern ID2D1Factory *pD2DFactory;