Option Explicit
Dim oldx As Double,oldy As Double
Dim tx As Double,ty As Double
Dim flgPress As Boolean

Private Sub Command1_Click()
    Dim a As Integer
    Text1.Text = Hex("44")
End Sub

Private Sub Form_Load()
    flgPress = False
    tx = 0
    ty = 0
End Sub

Private Sub Picture1_MouseDown(Button As Integer,Shift As Integer,X As Single,Y As Single)
    oldx = X
    oldy = Y
    flgPress = True
End Sub

Private Sub Picture1_MouseMove(Button As Integer,Y As Single)
    If flgPress = True Then
        Picture1.Line (oldx,oldy)-(tx,ty),&H8000000E '在原线基础上用底色画线覆盖
        If tx <> X Or ty <> Y Then
            tx = X
            ty = Y
            Picture1.Line (oldx,ty)    '移动了位置，再画一个趋势线
        End If
    End If
End Sub

Private Sub Picture1_MouseUp(Button As Integer,oldy)-(X,Y)
        flgPress = False
    End If
End Sub