使用Double-Buffer来实现无闪烁动态折线图

转自：http://blog.csdn.net/Knight94/archive/2006/08/18/1094078.aspx

//--------------------------- A Demo using Double-Buffer in GDI+ -------------------------------

//----------------------------------------------------------------------------------------------

//---File: frmGraphView

//---Description: A demo using double-buffer in GDI+

//---Author: Knight

//---Date: Jul.3, 2006

//----------------------------------------------------------------------------------------------

//---------------------------{A Demo using Double-Buffer in GDI+}-------------------------------

using System;

using System.Drawing;

using System.Collections;

using System.ComponentModel;

using System.Windows.Forms;

using System.Data;

namespace GraphView

{

using System.Threading;

/// <summary>

/// Summary description for Form1.

/// </summary>

public class frmGraphView : System.Windows.Forms.Form

{

private System.Windows.Forms.PictureBox picGraph;

/// <summary>

/// Required designer variable.

/// </summary>

private System.ComponentModel.Container components = null;

private clsDrawThread myDrawThread = null;

private Thread thdDraw = null;

public frmGraphView()

{

//

// Required for Windows Form Designer support

//

InitializeComponent();

//

// TODO: Add any constructor code after InitializeComponent call

//

}

/// <summary>

/// Clean up any resources being used.

/// </summary>

protected override void Dispose( bool disposing )

{

if( disposing )

{

if (components != null)

{

components.Dispose();

}

}

base.Dispose( disposing );

}

#region Windows Form Designer generated code

/// <summary>

/// Required method for Designer support - do not modify

/// the contents of this method with the code editor.

/// </summary>

private void InitializeComponent()

{

this.picGraph = new System.Windows.Forms.PictureBox();

this.SuspendLayout();

//

// picGraph

//

this.picGraph.BackColor = System.Drawing.Color.Black;

this.picGraph.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;

this.picGraph.Dock = System.Windows.Forms.DockStyle.Fill;

this.picGraph.Location = new System.Drawing.Point(0, 0);

this.picGraph.Name = "picGraph";

this.picGraph.Size = new System.Drawing.Size(498, 375);

this.picGraph.TabIndex = 0;

this.picGraph.TabStop = false;

this.picGraph.Paint += new System.Windows.Forms.PaintEventHandler(this.picGraph_Paint);

//

// frmGraphView

//

this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);

this.ClientSize = new System.Drawing.Size(498, 375);

this.Controls.Add(this.picGraph);

this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle;

this.MaximizeBox = false;

this.Name = "frmGraphView";

this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;

this.Text = "Graph View";

this.Closing += new System.ComponentModel.CancelEventHandler(this.frmGraphView_Closing);

this.Load += new System.EventHandler(this.frmGraphView_Load);

this.ResumeLayout(false);

}

#endregion

/// <summary>

/// The main entry point for the application.

/// </summary>

[STAThread]

static void Main()

{

Application.Run(new frmGraphView());

}

private void frmGraphView_Load(object sender, System.EventArgs e)

{

// Create thread class

myDrawThread = new clsDrawThread( this, new DrawHandler( RefreshPictureBox ),

picGraph.ClientSize.Width, picGraph.ClientSize.Height );

// Start sub thread to draw

thdDraw = new Thread( new ThreadStart( myDrawThread.DrawGraph ) );

thdDraw.Start();

}

private void RefreshPictureBox()

{

// Refresh picturebox

picGraph.Invalidate( picGraph.Region );

}

private void frmGraphView_Closing(object sender, System.ComponentModel.CancelEventArgs e)

{

// Close thread

myDrawThread.IsStop = true;

thdDraw.Join( 1 );

}

private void picGraph_Paint(object sender, System.Windows.Forms.PaintEventArgs e)

{

// Draw image

e.Graphics.DrawImage( myDrawThread.DrawImage,

picGraph.ClientRectangle,

picGraph.ClientRectangle,

GraphicsUnit.Pixel );

}

}

public delegate void DrawHandler();

public class clsDrawThread

{

private Bitmap bitGraph = null;

private bool blnStop = false;

private int nStartY = -1;

private int nEndY = -1;

private Random ranPoint = null;

private int nWidth = 0;

private int nHeight = 0;

private Form frmParent;

private DrawHandler pHandler = null;

/// <summary>

/// Constructor

/// </summary>

/// <param name="pParent"></param>

/// <param name="Handler"></param>

/// <param name="Width"></param>

/// <param name="Height"></param>

public clsDrawThread( Form pParent, DrawHandler Handler, int Width, int Height )

{

// Init class member

nWidth = Width;

nHeight = Height;

frmParent = pParent;//Parent form

pHandler = Handler;//Call back delegate

// Create double buffer

bitGraph = new Bitmap( nWidth, nHeight );

ranPoint = new Random( nHeight );//Create random

}

public bool IsStop

{

set{ blnStop = value;}

}

public Image DrawImage

{

get{ return bitGraph;}

}

/// <summary>

/// Sub thread entry function

/// </summary>

public void DrawGraph()

{

while( !blnStop )

{

Thread.Sleep( 400 );

if( blnStop ) break;

//Redraw bitmap

RedrawImage();

//Refresh pictorebox

try

{

frmParent.Invoke( pHandler );

}

catch{ break;}

}

}

/// <summary>

/// Re-draw image

/// </summary>

private void RedrawImage()

{

const int CLIP_WIDTH = 10;

Bitmap bitNew = new Bitmap( nWidth, nHeight );

Graphics gImage = Graphics.FromImage( bitNew );

// Use black color to fill the entire rectangle

gImage.FillRectangle( new SolidBrush( Color.Black ),

new Rectangle( new Point( 0, 0),

new Size( nWidth, nHeight ) ) );

// Copy image from source image

gImage.DrawImage( bitGraph,

new Rectangle( 0,0, nWidth - CLIP_WIDTH, nHeight ),

new Rectangle( CLIP_WIDTH,0, nWidth - CLIP_WIDTH, nHeight ),

GraphicsUnit.Pixel );

// Draw new clip image

if( nStartY < 0 )

nStartY = ranPoint.Next() % nHeight;

else

nStartY = nEndY;

nEndY = ranPoint.Next() % nHeight;

// Draw new line

gImage.DrawLine( new Pen( Color.Red, 1.5f ),

new Point( nWidth - CLIP_WIDTH, nStartY ),

new Point( nWidth - 1, nEndY ) );

// Set new image and release old image

Bitmap bitOld = bitGraph;

bitGraph = bitNew;

bitOld.Dispose();

}

}

}