form1.vb

Visual.Basic.NET实用编程百例-47.6M.zip

Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Math
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 dispose 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
    Friend WithEvents MainMenu1 As System.Windows.Forms.MainMenu
    Friend WithEvents MenuItem2 As System.Windows.Forms.MenuItem
    Friend WithEvents MenuItem3 As System.Windows.Forms.MenuItem
    Friend WithEvents mRect As System.Windows.Forms.MenuItem
    Friend WithEvents mClear As System.Windows.Forms.MenuItem
    Friend WithEvents mSp As System.Windows.Forms.MenuItem
    '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。
    Friend WithEvents Panel1 As System.Windows.Forms.Panel
    Friend WithEvents MenuItem1 As System.Windows.Forms.MenuItem
    Friend WithEvents MenuItem6 As System.Windows.Forms.MenuItem
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.MainMenu1 = New System.Windows.Forms.MainMenu
        Me.MenuItem1 = New System.Windows.Forms.MenuItem
        Me.MenuItem2 = New System.Windows.Forms.MenuItem
        Me.MenuItem3 = New System.Windows.Forms.MenuItem
        Me.mRect = New System.Windows.Forms.MenuItem
        Me.mClear = New System.Windows.Forms.MenuItem
        Me.mSp = New System.Windows.Forms.MenuItem
        Me.MenuItem6 = New System.Windows.Forms.MenuItem
        Me.Panel1 = New System.Windows.Forms.Panel
        Me.SuspendLayout()
        '
        'MainMenu1
        '
        Me.MainMenu1.MenuItems.AddRange(New System.Windows.Forms.MenuItem() {Me.MenuItem1})
        '
        'MenuItem1
        '
        Me.MenuItem1.Index = 0
        Me.MenuItem1.MenuItems.AddRange(New System.Windows.Forms.MenuItem() {Me.MenuItem2, Me.MenuItem3, Me.mRect, Me.mClear, Me.mSp, Me.MenuItem6})
        Me.MenuItem1.Text = "操作"
        '
        'MenuItem2
        '
        Me.MenuItem2.Index = 0
        Me.MenuItem2.Text = "直线"
        '
        'MenuItem3
        '
        Me.MenuItem3.Index = 1
        Me.MenuItem3.Text = "圆形"
        '
        'mRect
        '
        Me.mRect.Index = 2
        Me.mRect.Text = "矩形"
        '
        'mClear
        '
        Me.mClear.Index = 3
        Me.mClear.Text = "清除"
        '
        'mSp
        '
        Me.mSp.Index = 4
        Me.mSp.Text = "-"
        '
        'MenuItem6
        '
        Me.MenuItem6.Index = 5
        Me.MenuItem6.Text = "退出"
        '
        'Panel1
        '
        Me.Panel1.Location = New System.Drawing.Point(0, 0)
        Me.Panel1.Name = "Panel1"
        Me.Panel1.Size = New System.Drawing.Size(456, 272)
        Me.Panel1.TabIndex = 0
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
        Me.ClientSize = New System.Drawing.Size(456, 273)
        Me.Controls.Add(Me.Panel1)
        Me.Menu = Me.MainMenu1
        Me.Name = "Form1"
        Me.Text = "使用鼠标画图"
        Me.ResumeLayout(False)

    End Sub

#End Region
    'fl表示绘图方式
    Dim fl As Integer = 0
    '关于Line的参数
    Dim lp(100, 20) As Point
    Dim lf As Boolean
    '记录每条折线所包含的线段个数
    Dim ln(100) As Integer
    '标志是否为左键点击
    Dim lleft As Boolean
    '关于Circle的参数
    Dim cp1(100) As Point
    Dim cp2(100) As Point
    Dim cr(100) As Single
    Dim cf As Boolean
    '关于Rectangle的参数
    Dim rp1(100) As Point
    Dim rp2(100) As Point
    Dim rf As Boolean
    '记录已作图形的个数
    Dim l As Integer
    Dim c As Integer
    Dim r As Integer

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Panel1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D
        Panel1.Dock = DockStyle.Fill
        Panel1.BackColor = Color.White
        '初始化
        Init()
    End Sub

    Private Sub Init()
        '初始化绘图参数

        Dim i, j As Integer
        For i = 0 To 100
            ln(i) = 0
        Next
        lf = True
        lleft = True
        cf = True
        rf = True
        l = 0
        c = 0
        r = 0
    End Sub

    Private Sub MenuItem2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem2.Click
        fl = 1

    End Sub

    Private Sub MenuItem3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem3.Click
        fl = 2
    End Sub

    Private Sub mRect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mRect.Click
        fl = 3
    End Sub

    Private Sub mClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles mClear.Click
        fl = 4
        '清除所有图形
        Panel1.Invalidate()
        '初始化
        Init()
    End Sub

    Private Sub Panel1_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Panel1.MouseDown
        Select Case fl
            Case 1
                If e.Button = MouseButtons.Left Then
                    '判断为左键点击
                    If lf Then
                        '获取整条折线的第一点
                        lp(l, ln(l)) = New Point(e.X, e.Y)
                        lf = False
                    ElseIf Not lf Then
                        '因为最后一条橡皮筋就是要画的线段
                        '所以这里无须再获取鼠标点的坐标
                        '也无须再调用重绘函数
                        ln(l) = ln(l) + 1
                    End If
                ElseIf e.Button = MouseButtons.Right Then
                    '判断为右键点击
                    lleft = False
                    Panel1.Invalidate()
                End If
            Case 2
                If cf Then
                    cp1(c) = New Point(e.X, e.Y)
                    cf = False
                ElseIf Not cf Then
                    cf = True
                    Panel1.Invalidate()
                End If
            Case 3
                If rf Then
                    rp1(r) = New Point(e.X, e.Y)
                    rf = False
                ElseIf Not rf Then
                    rf = True
                    Panel1.Invalidate()
                End If
        End Select
    End Sub

    Private Sub Panel1_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Panel1.Paint
        Dim rect1 As Rectangle
        Dim rect2 As Rectangle
        Dim i, j As Integer
        Dim g As Graphics = e.Graphics
        g.SmoothingMode = SmoothingMode.AntiAlias

        '刷新之前绘制的图形
        If l > 0 Then
            For i = 0 To l - 1
                For j = 0 To ln(i) - 1
                    g.DrawLine(Pens.White, lp(i, j), lp(i, j + 1))
                    g.DrawLine(Pens.Black, lp(i, j), lp(i, j + 1))
                Next
            Next
        End If

        If c > 0 Then
            For i = 0 To c - 1
                rect1 = New Rectangle(cp1(i).X - cr(i), cp1(i).Y - cr(i), cr(i) * 2, cr(i) * 2)
                rect2 = New Rectangle(cp1(i).X - cr(i), cp1(i).Y - cr(i), cr(i) * 2, cr(i) * 2)
                g.DrawEllipse(Pens.White, rect1)
                g.DrawEllipse(Pens.Black, rect2)
            Next
        End If

        If r > 0 Then
            For i = 0 To r - 1
                rect1 = New Rectangle(Min(rp1(i).X, rp2(i).X), Min(rp1(i).Y, rp2(i).Y), Abs(rp1(i).X - rp2(i).X), Abs(rp1(i).Y - rp2(i).Y))
                rect2 = New Rectangle(Min(rp1(i).X, rp2(i).X), Min(rp1(i).Y, rp2(i).Y), Abs(rp1(i).X - rp2(i).X), Abs(rp1(i).Y - rp2(i).Y))
                g.DrawRectangle(Pens.White, rect1)
                g.DrawRectangle(Pens.Black, rect2)
            Next
        End If

        Select Case fl
            Case 1
                '刷新本条折线上已经画完的线段
                If ln(l) >= 1 Then
                    For j = 0 To ln(l) - 1
                        g.DrawLine(Pens.White, lp(l, j), lp(l, j + 1))
                        g.DrawLine(Pens.Black, lp(l, j), lp(l, j + 1))
                    Next
                End If
                If lleft Then
                    If Not lf Then
                        '绘制橡皮筋（包含了绘制最终的结果）
                        g.DrawLine(Pens.White, lp(l, ln(l)), lp(l, ln(l) + 1))
                        g.DrawLine(Pens.Black, lp(l, ln(l)), lp(l, ln(l) + 1))
                    End If
                Else
                    If ln(l) > 0 Then
                        '本条折线画完，准备画下一条
                        l = l + 1
                    End If
                    lf = True
                    lleft = True
                End If
            Case 2
                If Not cf Then
                    '绘制橡皮筋
                    cr(c) = Sqrt((cp2(c).X - cp1(c).X) * (cp2(c).X - cp1(c).X) + (cp2(c).Y - cp1(c).Y) * (cp2(c).Y - cp1(c).Y))
                    rect1 = New Rectangle(cp1(c).X - cr(c), cp1(c).Y - cr(c), cr(c) * 2, cr(c) * 2)
                    rect2 = New Rectangle(cp1(c).X - cr(c), cp1(c).Y - cr(c), cr(c) * 2, cr(c) * 2)
                    g.DrawLine(Pens.White, cp1(c), cp2(c))
                    g.DrawLine(Pens.Black, cp1(c), cp2(c))
                    g.DrawEllipse(Pens.White, rect1)
                    g.DrawEllipse(Pens.Black, rect2)
                Else
                    cr(c) = Sqrt((cp2(c).X - cp1(c).X) * (cp2(c).X - cp1(c).X) + (cp2(c).Y - cp1(c).Y) * (cp2(c).Y - cp1(c).Y))
                    rect1 = New Rectangle(cp1(c).X - cr(c), cp1(c).Y - cr(c), cr(c) * 2, cr(c) * 2)
                    rect2 = New Rectangle(cp1(c).X - cr(c), cp1(c).Y - cr(c), cr(c) * 2, cr(c) * 2)
                    g.DrawEllipse(Pens.White, rect1)
                    g.DrawEllipse(Pens.Black, rect2)
                    c = c + 1
                End If
            Case 3
                If Not rf Then
                    '绘制橡皮筋
                    g.DrawLine(Pens.White, rp1(r), rp2(r))
                    g.DrawLine(Pens.Black, rp1(r), rp2(r))
                    '必须考虑到用户点击的点未必一定是矩形的左上角点和右下角点，
                    '而是有其他可能
                    'Min()是求两数中较小一个的函数
                    'Abs()是求绝对值的函数
                    rect1 = New Rectangle(Min(rp1(r).X, rp2(r).X), Min(rp1(r).Y, rp2(r).Y), Abs(rp1(r).X - rp2(r).X), Abs(rp1(r).Y - rp2(r).Y))
                    rect2 = New Rectangle(Min(rp1(r).X, rp2(r).X), Min(rp1(r).Y, rp2(r).Y), Abs(rp1(r).X - rp2(r).X), Abs(rp1(r).Y - rp2(r).Y))
                    g.DrawRectangle(Pens.White, rect1)
                    g.DrawRectangle(Pens.Black, rect2)
                Else
                    rect1 = New Rectangle(Min(rp1(r).X, rp2(r).X), Min(rp1(r).Y, rp2(r).Y), Abs(rp1(r).X - rp2(r).X), Abs(rp1(r).Y - rp2(r).Y))
                    rect2 = New Rectangle(Min(rp1(r).X, rp2(r).X), Min(rp1(r).Y, rp2(r).Y), Abs(rp1(r).X - rp2(r).X), Abs(rp1(r).Y - rp2(r).Y))
                    g.DrawRectangle(Pens.White, rect1)
                    g.DrawRectangle(Pens.Black, rect2)
                    r = r + 1
                End If
            Case 4
                '用白刷子覆盖所有图形
                g.FillRectangle(Brushes.White, Panel1.ClientRectangle)
                fl = 0
        End Select
    End Sub

    Private Sub Panel1_MouseMove(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Panel1.MouseMove
        Select Case fl
            Case 1
                If lleft Then
                    If Not lf Then
                        '整个折线绘制过程中跟踪鼠标的移动
                        lp(l, ln(l) + 1) = New Point(e.X, e.Y)
                        '绘制橡皮筋
                        Panel1.Invalidate()
                    End If
                End If
            Case 2
                If Not cf Then
                    cp2(c) = New Point(e.X, e.Y)
                    Panel1.Invalidate()
                End If
            Case 3
                If Not rf Then
                    rp2(r) = New Point(e.X, e.Y)
                    Panel1.Invalidate()
                End If
        End Select
    End Sub

    Private Sub MenuItem6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem6.Click
        End
    End Sub
End Class