vb System.Windows.Forms.VisualStyles.VisualStyleRenderer.GetBackgroundRegion类(方法)实例源码

' Calculate and set the clipping region for the control  
' so that the corners of the title bar are rounded.
Private Sub SetClipRegion()
    If Not Application.RenderWithVisualStyles Then
        Return
    End If

    Using g As Graphics = Me.CreateGraphics()
        ' Get the current region for the window caption.
        If SetRenderer(windowElements("windowCaption")) Then
            Dim clipRegion As Region = _
                renderer.GetBackgroundRegion(g, _
                elementRectangles("windowCaption"))

            ' Get the client rectangle, but exclude the   
            ' region of the window caption.
            Dim height As Integer = _
                CInt(clipRegion.GetBounds(g).Height)
            Dim nonCaptionRect As _
                New Rectangle(ClientRectangle.X, _
                ClientRectangle.Y + height, _
                ClientRectangle.Width, _
                ClientRectangle.Height - height)

            ' Add the rectangle to the caption region, and  
            ' make this region the form's clipping region.
            clipRegion.Union(nonCaptionRect)
            Me.Region = clipRegion
        End If
    End Using
End Sub