Question

窗体上放置一图片框，通过鼠标在图片框内的拖动画红色的实心圆

窗体上放置一图片框，通过鼠标在图片框内的拖动画红色的实心圆。鼠标左键按下点为圆心，鼠标左键释放点到鼠标按下点所拖动的距离为半径。当按下鼠标右键时，清除图片框上的图形。

Answer 1

Dim cx As Integer
Dim cy As Integer

Private Sub Picture1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
If Button = 1 Then
cx = X
cy = Y
PSet (X, Y)
End If
If Button = 2 Then
Picture1.Cls
End If
End Sub

Private Sub Picture1_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
If Button = 1 Then
r = Sqr((X - cx) ^ 2 + (Y - cy) ^ 2)
Picture1.FillStyle = 0
Picture1.FillColor = vbRed
Picture1.Circle (cx, cy), r
End If
End Sub