如何用VB做一个绘图程序

'窗体内添加一个Picture1,五个CommandButton,从1到5分别为:放大/缩小/清除/读取/保存

Option Explicit

'简单矢量绘图例子

'

'BY 嗷嗷叫的老马

'紫水晶工作室 http://www.m5home.com/



Private Const SS As Single = 1.3            '缩小/放大的倍数



Dim RecPoint() As String, MaxIndex As Long      '主要数据存储数组及其最大的下标

Dim P1X As Long, P1Y As Long, P2X As Long, P2Y As Long      '内部坐标系统的左上角坐标与右下角坐标



Private Sub Command1_Click()

    '清除显示,但不清除数据

    Picture1.Cls

End Sub



Private Sub Command2_Click()

    '从硬盘中读入点数据

    Dim Buff As String

    

    Open "c:\123.txt" For Binary As #1

        Buff = Space(LOF(1))

        Get #1, , Buff

    Close #1

    

    RecPoint() = Split(Buff, vbCrLf)

    Call DrawPoint

End Sub



Private Sub Command3_Click()

    '保存点数据

    Open "c:\123.txt" For Binary As #1

        Put #1, , Join(RecPoint(), vbCrLf)

    Close #1

End Sub



Private Sub Command4_Click()

    '放大,将'画布'变小就是放大

    P1Y = P1Y / SS: P2X = P2X / SS

    Picture1.Scale (P1X, P1Y)-(P2X, P2Y)        '改变坐标系统

    

    Call DrawPoint

End Sub



Private Sub Command5_Click()

    '缩小,将'画布'变小就是缩小

    P1Y = P1Y * SS: P2X = P2X * SS

    Picture1.Scale (P1X, P1Y)-(P2X, P2Y)        '改变坐标系统

    

    Call DrawPoint

End Sub



Private Sub Form_Load()

    P1X = 0: P1Y = 500

    P2X = 500: P2Y = 0

    

    Picture1.Scale (P1X, P1Y)-(P2X, P2Y)        '初始化坐标系统

    

    MaxIndex = -1: ReDim RecPoint(0)

End Sub



Private Sub Picture1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)

    Me.Caption = X & "/" & Y

    If (Button And vbLeftButton) = vbLeftButton Then    '按下鼠标左键时记录坐标并显示

        MaxIndex = MaxIndex + 1: ReDim Preserve RecPoint(MaxIndex)

        RecPoint(MaxIndex) = X & "," & Y

        Picture1.PSet (X, Y), vbBlack

    End If

End Sub



Private Sub DrawPoint()

    '绘图过程.

    Dim I As Long, PBuff() As String

    

    Picture1.Cls

    For I = 0 To UBound(RecPoint)

        PBuff = Split(RecPoint(I), ",")

        Picture1.PSet (PBuff(0), PBuff(1)), vbBlack

    Next I

End Sub