[DllImport("gdi32.dll")]
static extern bool ArcTo(IntPtr hdc, int nLeftRect, int nTopRect,
int nRightRect, int nBottomRect, int nXRadial1, int nYRadial1,
int nXRadial2, int nYRadial2);
VB Signature:
Declare Function ArcTo Lib "gdi32.dll" (ByVal hdc As IntPtr, _
ByVal nLeftRect As Integer, ByVal nTopRect As Integer, _
ByVal nRightRect As Integer, ByVal nBottomRect As Integer, _
ByVal nXRadial1 As Integer, ByVal nYRadial1 As Integer, _
ByVal nXRadial2 As Integer, ByVal nYRadial2 As Integer) As Boolean