form1.vb

苏金明编写的《用VB.NET和VC#.NET开发交互式CAD系统》一书的源代码

Imports System.Drawing.Drawing2D

Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows 窗体设计器生成的代码 "

    Public Sub New()
        MyBase.New()

        '该调用是 Windows 窗体设计器所必需的。
        InitializeComponent()

        '在 InitializeComponent() 调用之后添加任何初始化

    End Sub

    '窗体重写处置以清理组件列表。
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Windows 窗体设计器所必需的
    Private components As System.ComponentModel.IContainer

    '注意：以下过程是 Windows 窗体设计器所必需的
    '可以使用 Windows 窗体设计器修改此过程。
    '不要使用代码编辑器修改它。
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
        Me.ClientSize = New System.Drawing.Size(292, 266)
        Me.Name = "Form1"
        Me.Text = "区域"

    End Sub

#End Region

    Protected Overrides Sub OnPaint(ByVal e As Windows.Forms.PaintEventArgs)
        Dim g As Graphics = e.Graphics
        '定义一个含有多边形的路径
        Dim points As PointF() = { _
           New PointF(10, 10), _
           New PointF(200, 20), _
           New PointF(500, 200), _
           New PointF(300, 250), _
           New PointF(100, 150)}
        Dim gp As New GraphicsPath()
        gp.AddPolygon(points)
        '利用该路径生成多边形区域
        Dim reg As New Region(gp)
        '在该区域中剔除一个矩形区域
        reg.Exclude(New Rectangle(90, 60, 150, 60))
        '绘出最后得到的区域
        g.FillRegion(Brushes.Blue, reg)
        '得到并绘制多边形区域的包围矩形
        Dim rect As RectangleF = reg.GetBounds(g)
        g.DrawRectangle(Pens.Red, rect.Left, rect.Top, rect.Width, rect.Height)
        '确定下面两个点是否在区域中
        Dim p1 As New PointF(300, 100)
        Dim p2 As New PointF(100, 100)
        InRegion(reg, p1)
        InRegion(reg, p2)
        gp.Dispose()
        reg.Dispose()

    End Sub

    Private Sub InRegion(ByVal reg As Region, ByVal p As PointF)
        '确定某点是否位于指定区域中，并在调试窗口中输出
        If reg.IsVisible(p) Then
            Console.WriteLine("点(" & Str(p.X) & "," & Str(p.Y) & ")在指定区域内")
        Else
            Console.WriteLine("点(" & Str(p.X) & "," & Str(p.Y) & ")不在指定区域内")
        End If
    End Sub

End Class