using System.Text;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
protected void Page_Load(object sender, EventArgs e)
{
String sCode = String.Empty;
//清除該頁輸出緩存，設置該頁無緩存
Response.Buffer = true;
Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
Response.Expires = 0;
Response.CacheControl = "no-cache";
Response.AppendHeader("Pragma", "No-Cache");
// '將驗證碼圖片寫入記憶體流，並將其以 "image/Png" 格式輸出
MemoryStream oStream = new MemoryStream();
try
{
CreateValidateCodeImage(oStream, sCode, 4, 100, 40, 18);
Session["_ValidateCode"] = sCode;
Response.ClearContent();
Response.ContentType = "image/Png";
Response.BinaryWrite(oStream.ToArray());
}
finally
{
// '釋放資源
oStream.Dispose();
}
}
/// <summary>
/// 產生圖形驗證碼。
/// </summary>
/// <param name="MemoryStream">記憶體資料流。</param>
/// <param name="Code">傳出驗證碼。</param>
/// <param name="CodeLength">驗證碼字元數。</param>
/// <param name="Width"></param>
/// <param name="Height"></param>
/// <param name="FontSize"></param>
public void CreateValidateCodeImage(MemoryStream MemoryStream, String Code, int CodeLength, int Width, int Height, int FontSize)
{
Bitmap oBmp;
oBmp = CreateValidateCodeImage(Code, CodeLength, Width, Height, FontSize);
try
{
oBmp.Save(MemoryStream, ImageFormat.Png);
}
finally { oBmp.Dispose(); }
}
/// <summary>
/// 產生圖形驗證碼。
/// </summary>
/// <param name="Code">傳出驗證碼。</param>
/// <param name="CodeLength">驗證碼字元數。</param>
/// <param name="Width"></param>
/// <param name="Height"></param>
/// <param name="FontSize"></param>
/// <returns></returns>
public Bitmap CreateValidateCodeImage(String Code, int CodeLength, int Width, int Height, int FontSize)
{
String sCode = String.Empty;
//顏色列表，用於驗證碼、噪線、噪點
Color[] oColors ={
System.Drawing.Color.Black,
System.Drawing.Color.Red,
System.Drawing.Color.Blue,
System.Drawing.Color.Green,
System.Drawing.Color.Orange,
System.Drawing.Color.Brown,
System.Drawing.Color.Brown,
System.Drawing.Color.DarkBlue
};
//字體列表，用於驗證碼
string[] oFontNames ={ "Times New Roman", "MS Mincho", "Book Antiqua", "Gungsuh", "PMingLiU", "Impact" };
//驗證碼的字元集，去掉了一些容易混淆的字元
char[] oCharacter = {
'2',
'3',
'4',
'5',
'6',
'8',
'9',
'A',
'B',
'C',
'D',
'E',
'F',
'G',
'H',
'J',
'K',
'L',
'M',
'N',
'P',
'R',
'S',
'T',
'W',
'X',
'Y'
};
Random oRnd = new Random();
Bitmap oBmp = null;
Graphics oGraphics = null;
int N1 = 0;
System.Drawing.Point oPoint1 = default(System.Drawing.Point);
System.Drawing.Point oPoint2 = default(System.Drawing.Point);
string sFontName = null;
Font oFont = null;
Color oColor = default(Color);
//生成驗證碼字串
for (N1 = 0; N1 <= CodeLength - 1; N1++)
{
sCode += oCharacter[oRnd.Next(oCharacter.Length)];
}
oBmp = new Bitmap(Width, Height);
oGraphics = Graphics.FromImage(oBmp);
oGraphics.Clear(System.Drawing.Color.White);
try
{
for (N1 = 0; N1 <= 4; N1++)
{
//畫噪線
oPoint1.X = oRnd.Next(Width);
oPoint1.Y = oRnd.Next(Height);
oPoint2.X = oRnd.Next(Width);
oPoint2.Y = oRnd.Next(Height);
oColor = oColors[oRnd.Next(oColors.Length)];
oGraphics.DrawLine(new Pen(oColor), oPoint1, oPoint2);
}
for (N1 = 0; N1 <= sCode.Length - 1; N1++)
{
//畫驗證碼字串
sFontName = oFontNames[oRnd.Next(oFontNames.Length)];
oFont = new Font(sFontName, FontSize, FontStyle.Italic);
oColor = oColors[oRnd.Next(oColors.Length)];
oGraphics.DrawString(sCode[N1].ToString(), oFont, new SolidBrush(oColor), Convert.ToSingle(N1) * FontSize + 10, Convert.ToSingle(8));
}
for (int i = 0; i <= 30; i++)
{
//畫噪點
int x = oRnd.Next(oBmp.Width);
int y = oRnd.Next(oBmp.Height);
Color clr = oColors[oRnd.Next(oColors.Length)];
oBmp.SetPixel(x, y, clr);
}
Code = sCode;
return oBmp;
}
finally
{
oGraphics.Dispose();
}
}
=====================================
改编自博友的原代码为C#
http://www.cnblogs.com/jeff377/archive/2008/10/29/1322471.html
效果图如下：
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