由12306动态验证码想到的ASP.NET实现动态GIF验证码(附源码)
景:
12306网站推出“彩色动态验证码机制”,新版验证码不但经常出现字符叠压,还不停抖动,不少人大呼“看不清”,称“那个验证码,是毕加索的抽象画么!”铁总客服则表示:为了能正常购票只能这样。而多家抢票软件接近“报废”,引发不少网友不满的吐槽称“太抽象太艺术了”。
正题:
以前做项目有时候也会用到验证码,但基本都是静态的。这次也想凑凑12306的热闹。
闲言少续,切入正题,先上代码,实现方法:
public void ShowCode(){//对象实例化Validate GifValidate = new Validate();#region 对验证码进行设置(不进行设置时,将以默认值生成)//验证码位数,不小于4位GifValidate.ValidateCodeCount = 4;//验证码字体型号(默认13)GifValidate.ValidateCodeSize = 13;//验证码图片高度,高度越大,字符的上下偏移量就越明显GifValidate.ImageHeight = 23;//验证码字符及线条颜色(需要参考颜色类)GifValidate.DrawColor = System.Drawing.Color.BlueViolet;//验证码字体(需要填写服务器安装的字体)GifValidate.ValidateCodeFont = "Arial";//验证码字符是否消除锯齿GifValidate.FontTextRenderingHint = false;//定义验证码中所有的字符(","分离),似乎暂时不支持中文GifValidate.AllChar = "1,2,3,4,5,6,7,8,9,0,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,W,X,Y,Z";#endregion//输出图像(Session名称)GifValidate.OutPutValidate("GetCode");}
调用主要方法:
public class Validate{public string AllChar = "1,2,3,4,5,6,7,8,9,0,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,W,X,Y,Z";public Color DrawColor = Color.BlueViolet;public bool FontTextRenderingHint = false;public int ImageHeight = 0x17;private byte TrueValidateCodeCount = 4;protected string ValidateCode = "";public string ValidateCodeFont = "Arial";public float ValidateCodeSize = 13f;private void CreateImageBmp(out Bitmap ImageFrame){char[] chArray = this.ValidateCode.ToCharArray(0, this.ValidateCodeCount);int width = (int) (((this.TrueValidateCodeCount * this.ValidateCodeSize) * 1.3) + 4.0);ImageFrame = new Bitmap(width, this.ImageHeight);Graphics graphics = Graphics.FromImage(ImageFrame);graphics.Clear(Color.White);Font font = new Font(this.ValidateCodeFont, this.ValidateCodeSize, FontStyle.Bold);Brush brush = new SolidBrush(this.DrawColor);int maxValue = (int) Math.Max((float) ((this.ImageHeight - this.ValidateCodeSize) - 3f), (float) 2f);Random random = new Random();for (int i = 0; i < this.TrueValidateCodeCount; i++){int[] numArray = new int[] { (((int) (i * this.ValidateCodeSize)) + random.Next(1)) + 3, random.Next(maxValue) };Point point = new Point(numArray[0], numArray[1]);if (this.FontTextRenderingHint){graphics.TextRenderingHint = TextRenderingHint.SingleBitPerPixel;}else{graphics.TextRenderingHint = TextRenderingHint.AntiAlias;}graphics.DrawString(chArray[i].ToString(), font, brush, (PointF) point);}graphics.Dispose();}private void CreateImageGif(){AnimatedGifEncoder encoder = new AnimatedGifEncoder();MemoryStream stream = new MemoryStream();encoder.Start();encoder.SetDelay(5);encoder.SetRepeat(0);for (int i = 0; i < 10; i++){Bitmap bitmap;this.CreateImageBmp(out bitmap);this.DisposeImageBmp(ref bitmap);bitmap.Save(stream, ImageFormat.Png);encoder.AddFrame(Image.FromStream(stream));stream = new MemoryStream();}encoder.OutPut(ref stream);HttpContext.Current.Response.ClearContent();HttpContext.Current.Response.ContentType = "p_w_picpath/Gif";HttpContext.Current.Response.BinaryWrite(stream.ToArray());stream.Close();stream.Dispose();}private void CreateValidate(){this.ValidateCode = "";string[] strArray = this.AllChar.Split(new char[] { ',' });int index = -1;Random random = new Random();for (int i = 0; i < this.ValidateCodeCount; i++){if (index != -1){random = new Random((i * index) * ((int) DateTime.Now.Ticks));}int num3 = random.Next(0x23);if (index == num3){this.CreateValidate();}index = num3;this.ValidateCode = this.ValidateCode + strArray[index];}if (this.ValidateCode.Length > this.TrueValidateCodeCount){this.ValidateCode = this.ValidateCode.Remove(this.TrueValidateCodeCount);}}private void DisposeImageBmp(ref Bitmap ImageFrame){Graphics graphics = Graphics.FromImage(ImageFrame);Pen pen = new Pen(this.DrawColor, 1f);Random random = new Random();Point[] pointArray = new Point[2];for (int i = 0; i < 15; i++){pointArray[0] = new Point(random.Next(ImageFrame.Width), random.Next(ImageFrame.Height));pointArray[1] = new Point(random.Next(ImageFrame.Width), random.Next(ImageFrame.Height));graphics.DrawLine(pen, pointArray[0], pointArray[1]);}graphics.Dispose();}public void OutPutValidate(string ValidateCodeSession){this.CreateValidate();this.CreateImageGif();HttpContext.Current.Session[ValidateCodeSession] = this.ValidateCode;}public byte ValidateCodeCount{get{return this.TrueValidateCodeCount;}set{if (value > 4){this.TrueValidateCodeCount = value;}}}}
验证码效果:
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