编写使用Bresenham算法画圆，为什么执行的时候老是溢出？不知道问题出在哪里~帮忙 谢谢
Bresenham算法代码：
Private Sub lineBresenham(x1, y1, x2, y2)
    Dim m, deltaX, deltaY, e As Double
    Dim i, x, y As Integer
    e = 0
   
    If Abs(deltaX) >= Abs(deltaY) Then
        m = deltaY / CDbl(deltaX)
        For i = 0 To Abs(deltaX)
            Picture1.PSet (x, y)
            x = x + Sgn(deltaX)
            e = e + Abs(m)
            
            If e > 0 Then
                y = y + Sgn(deltaX)
                e = e - 1
            End If
        Next i
    ElseIf Abs(deltaX) = 0 Then
        For i = o To Abs(deltaY)
            Picture1.PSet (x, y)
            y = y + Sgn(deltaY)
        Next i
    Else
        m = deltaX / CDbl(deltaY)
        For i = 0 To Abs(deltaY)
            Picture1.PSet (x, y)
            y = y + Sgn(deltaY)
            e = e + Abs(m)
            
            If e > 0 Then
                x = x + Sgn(deltaX)
                e = e - 1
            End If
        Next i
    End If
        
End Sub
其他的：
Dim command As Integer
Dim x1, y1 As Integer
Dim x2, y2 As Integer
Dim x0, y0 As Integer
Dim press As Boolean
Dim xnow, ynow As Integer

Private Sub Picture1_MouseDown(Button As Integer, Shift As Integer, x As Single, y As Single)
press = True
Picture1.DrawMode = 7
    x0 = x
    y0 = y
    xnow = x
    ynow = y
End Sub

Private Sub Picture1_MouseMove(Button As Integer, Shift As Integer, x As Single, y As Single)
 If press = True Then
  Call lineBresenham(x0, y0, xnow, ynow)
  Call lineBresenham(x0, y0, x, y)
  xnow = x
  ynow = y
 end if
End Sub

Private Sub Picture1_MouseUp(Button As Integer, Shift As Integer, x As Single, y As Single)
  Picture1.DrawMode = 13
  press = False
  Call lineBresenham(x0, y0, x, y)
End Sub

我居然没有分可以送，愧疚啊~