求助高手，用VB设计一个程序，实现一个圆绕椭圆轨迹运动的动画效果

这样就可以了,楼上的子函数M() 没有用到

Dim pi As Double
Dim runTime As Double
Dim a As Single, b As Single
Dim cntX As Single, cntY As Single
Dim r As Single
Private WithEvents Timer1 As Timer
Dim tX As Single, tY As Single
Dim tStep As Single

Private Sub Form_Load()
Me.ScaleMode = 3
Me.AutoRedraw = True
pi = Atn(1)
Set Timer1 = Controls.Add("vb.timer", "Timer1")

a = 50 '椭圆长轴
b = 30 '椭圆短轴
cntX = 100 '中心坐标X
cntY = 60 '中心坐标Y
r = 10 '圆半径
Timer1.Interval = 50 '运动间隔（毫秒）
tStep = pi / 10 '角度步长

Timer1.Enabled = True
End Sub

Private Sub Timer1_Timer()
runTime = runTime + 1
Dim Arg As Double
Arg = runTime * tStep
tX = cntX + a * Cos(Arg)
tY = cntY + b * Sin(Arg)
Me.Cls
Me.DrawStyle = 2
Me.Circle (cntX, cntY), a, , , , b / a
Me.DrawStyle = 0