Public Sub Complement_Region_Example(ByVal e As PaintEventArgs)

    ' Create the first rectangle and draw it to the screen in black.
    Dim regionRect As New Rectangle(20, 20, 100, 100)
    e.Graphics.DrawRectangle(Pens.Black, regionRect)

    ' Create the second rectangle and draw it to the screen in red.
    Dim complementRect As New Rectangle(90, 30, 100, 100)
    e.Graphics.DrawRectangle(Pens.Red, complementRect)

    ' create a region from the first rectangle.
    Dim myRegion As New [Region](regionRect)

    ' Create a complement region.
    Dim complementRegion As New [Region](complementRect)

    ' Get the complement of myRegion when combined with
    ' complementRegion.
    myRegion.Complement(complementRegion)

    ' Fill the complement area with blue.
    Dim myBrush As New SolidBrush(Color.Blue)
    e.Graphics.FillRegion(myBrush, myRegion)
End Sub

Public Sub Complement_RectF_Example(ByVal e As PaintEventArgs)

    ' Create the first rectangle and draw it to the screen in black.
    Dim regionRect As New Rectangle(20, 20, 100, 100)
    e.Graphics.DrawRectangle(Pens.Black, regionRect)

    ' Create the second rectangle and draw it to the screen in red.
    Dim complementRect As New RectangleF(90, 30, 100, 100)
    e.Graphics.DrawRectangle(Pens.Red, _
    Rectangle.Round(complementRect))

    ' Create a region using the first rectangle.
    Dim myRegion As New [Region](regionRect)

    ' Get the complement of the region combined with the second
    ' rectangle.
    myRegion.Complement(complementRect)

    ' Fill the complement area with blue.
    Dim myBrush As New SolidBrush(Color.Blue)
    e.Graphics.FillRegion(myBrush, myRegion)
End Sub

Public Sub Complement_Path_Example(ByVal e As PaintEventArgs)

    ' Create the first rectangle and draw it to the screen in black.
    Dim regionRect As New Rectangle(20, 20, 100, 100)
    e.Graphics.DrawRectangle(Pens.Black, regionRect)

    ' Create the second rectangle and draw it to the screen in red.
    Dim complementRect As New Rectangle(90, 30, 100, 100)
    e.Graphics.DrawRectangle(Pens.Red, complementRect)

    ' Create a graphics path and add the second rectangle to it.
    Dim complementPath As New GraphicsPath
    complementPath.AddRectangle(complementRect)

    ' Create a region using the first rectangle.
    Dim myRegion As New [Region](regionRect)

    ' Get the complement of myRegion when combined with
    ' complementPath.
    myRegion.Complement(complementPath)

    ' Fill the complement area with blue.
    Dim myBrush As New SolidBrush(Color.Blue)
    e.Graphics.FillRegion(myBrush, myRegion)
End Sub

' 导入命名空间
Imports System
Imports System.ComponentModel
Imports System.Windows.Forms
Imports System.Data
Imports System.Configuration
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Drawing.Text
Imports System.Globalization
Imports System.Text
Imports System.Collections

Public Class MainClass
    
    Shared Sub Main()
        
        Dim myform As Form = New CombinationsForm()
        Application.Run(myform)
    End Sub
End Class

Public Class CombinationsForm
    Inherits System.Windows.Forms.Form

    Public Sub New()
        MyBase.New()
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(244, 118)
        Me.Text = "CombinationsForm"
    End Sub

    Private Sub CombinationsForm_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        Dim g As Graphics = e.Graphics
        Dim width As Single = Me.ClientSize.Width 
        Dim height As Single = Me.ClientSize.Height
        Dim rect As RectangleF = New RectangleF(0, 0, width, height)
        Dim format As StringFormat = New StringFormat()
        format.Alignment = StringAlignment.Center
        format.LineAlignment = StringAlignment.Center

        Dim path1 As GraphicsPath = New GraphicsPath()
        Dim path2 As GraphicsPath = New GraphicsPath()

        Dim path1Rect As RectangleF = New RectangleF(0, 0, width * 2.0F / 3.0F, height)
        Dim path2rect As RectangleF = path1Rect
        path2rect.Offset(width * 1.0F / 3.0F, 0)
        path1.AddEllipse(path1Rect)
        path2.AddEllipse(path2rect)

        Dim region As Region = New Region(path1)
        region.Complement(path2)
        g.FillRegion(Brushes.Red, region)
        g.DrawString("Complement", Me.Font, Brushes.Black, rect, format)
        g.DrawRectangle(Pens.Black, rect.X, rect.Y, rect.Width, rect.Height)
        g.TranslateTransform(width, 0)
    End Sub
End Class