使用GDI+绘图时候发生的文图，图像只画了一部份，请教一下大家
如上图所示，当我用GDI+使图片旋转的时候，发现图片只显示了一部分，这是哪里出错了，想不出哪里出问题了，郁闷，下面是代码，请大家指教一下
Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
Dim ag As Graphics
ag = Me.CreateGraphics
Dim pbleft, pbtop As Single
pbleft = 312 + 60
pbtop = 169 + 60
Dim rotatePoint As New PointF(pbleft, pbtop)
Dim mymatrix As New Matrix
mymatrix.RotateAt(-10, rotatePoint, MatrixOrder.Append)
ag.Transform = mymatrix
Dim newImage As Image = Image.FromFile("D:\66.png")
Dim ulCorner As New PointF(312.0F, 169.0F)
ag.DrawImage(newImage, ulCorner)
ag.Dispose()
End Sub
