windows-server-2003/windows/advcore/gdiplus/demos/sidewalk/vmath.h

// Vector Math

#include <windows.h>
#include <objbase.h>
#include <math.h>
#include <gdiplus.h>
using namespace Gdiplus;

extern float DotProduct(PointF v1,PointF v2);
extern float Magnitude(PointF v);
extern PointF Normalize(PointF vPoint);