实时显示曲线

VERSION 5.00

Begin VB.Form Form1 

   Caption         =   "Form1"

   ClientHeight    =   5715

   ClientLeft      =   60

   ClientTop       =   450

   ClientWidth     =   8415

   LinkTopic       =   "Form1"

   ScaleHeight     =   381

   ScaleMode       =   3  'Pixel

   ScaleWidth      =   561

   StartUpPosition =   3  'Windows Default

   Begin VB.PictureBox Picture1 

      AutoRedraw      =   -1  'True

      BorderStyle     =   0  'None

      Height          =   4680

      Left            =   90

      ScaleHeight     =   312

      ScaleMode       =   3  'Pixel

      ScaleWidth      =   539

      TabIndex        =   0

      Top             =   75

      Width           =   8085

   End

   Begin VB.Timer Timer1 

      Interval        =   100

      Left            =   330

      Top             =   4980

   End

End

Attribute VB_Name = "Form1"

Attribute VB_GlobalNameSpace = False

Attribute VB_Creatable = False

Attribute VB_PredeclaredId = True

Attribute VB_Exposed = False

Option Explicit



Private Declare Function BitBlt Lib "gdi32" (ByVal hDestDC As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal dwRop As Long) As Long

Private Const SRCCOPY = &HCC0020

Dim l As Long

Dim oldy As Long

Dim newy As Long

Private Sub Form_Load()

    l = 0

    Picture1.Width = 400

    oldy = Picture1.Height / 3

    newy = Picture1.Height / 3

End Sub



Private Sub Timer1_Timer()

    Randomize Timer

    newy = Picture1.Height / 3 + 100 * Rnd

    If l + 20 < Picture1.Width Then

        Picture1.Line (l, oldy)-(l + 20, newy)

        l = l + 20

    Else

        BitBlt Picture1.hDC, 0, 0, Picture1.Width - 20, Picture1.Height, Picture1.hDC, 20, 0, SRCCOPY

        Picture1.Line (l - 20, oldy)-(l - 1, newy)

        Picture1.Refresh

    End If

    oldy = newy

End Sub