VB.NET实现PhotoShop的流动选取框

epoluodi

大家好，本人第一次发表文章（激动中），看了开发高手连续几篇谈到PhotoShop中流动选取框的文章，其实实现并不难，在这里我就用VB.NET实现，在.NET中提供了功能十分强大的GDI+，前篇C#用的也是GDI＋，我这里也用上！其实没有什么区别！希望对学VB.NET的人有帮助，下面是源码：

创建一个新的VB应用程序，一个窗口中添加一个时间（Timer）组件，Interval设置为50微妙，

Imports System.Drawing.Drawing2D
Imports System.Drawing.Graphics
Public Class Form1
    Inherits System.Windows.Forms.Form
    Private pen As pen                                 ´创建一个画笔对象
    Private GPath As New GraphicsPath                  ´实例化路径对象
    Private Dpattern() As Single = {5.0, 7.0}          ´实线的长度和虚线长度
    Private offset As Single = 0.0                     ´偏移值

#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
            GPath.Dispose()
            pen.Dispose()
        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。
    Friend WithEvents Timer1 As System.Windows.Forms.Timer
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.components = New System.ComponentModel.Container
        Me.Timer1 = New System.Windows.Forms.Timer(Me.components)
        ´
        ´Timer1
        ´
        Me.Timer1.Enabled = True
        Me.Timer1.Interval = 50
        ´
        ´Form1
        ´
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
        Me.ClientSize = New System.Drawing.Size(416, 166)
        Me.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle
        Me.MaximizeBox = False
        Me.MinimizeBox = False
        Me.Name = "Form1"
        Me.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen
        Me.Text = "Photo For VB.NET"

End Sub

#End Region

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Me.Refresh()            ´刷新窗口
    End Sub

    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        pen.DashOffset = offset                 ´设置偏移值
        e.Graphics.DrawPath(pen, GPath)         ´画路径

        ´改变偏移值的量
        offset += 1.0
        If offset / 100 = 1 Then
            offset = 0.0
        End If

End Sub

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
        GPath.AddString("电脑", _
                        New FontFamily("幼圆"), _
                        FontStyle.Bold + FontStyle.Italic, _
                        120.0F, _
                        New PointF(30.0F, 20.0F), _
                        New StringFormat)        ´添加一个字符路径
        pen = New Pen(Color.Black)               ´构造画笔
        pen.DashPattern = Dpattern               ´自定义的短划线和空白区域
        pen.DashStyle = DashStyle.Custom         ´此属性的 DashStyle.Custom 值指定：由 DashPattern 属性定义的短划线和空白区域的自定义图案
    End Sub
End Class
在WINXP＋SP1＋VS.NET2003编译通过

有不对的地方请指点