Captcha version 2.0 - coder.awas.vn

Diễn đàn ASP.NET & Sharepoint MOSS, WSS 2007 Captcha version 2.0

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tieuphu Thống chế Erich von Manstein 50 bài	30-05-2009 02:27:28 Lần trước post 1 bài về captcha rồi lần này thêm con nữa cho vui. Con này an toàn cao hơn vì sử dụng nhiều loại hình chống bot regconition. using System; using System.Data; using System.Drawing; namespace captcha { public partial class _Default : System.Web.UI.Page { private Bitmap TransformImage(Bitmap bmp, Random rnd) { int width = bmp.Width; int height = bmp.Height; double distort = rnd.Next(5, 15) * (rnd.Next(10) == 1 ? 1 : -1); // Copy the image so that we're always using the original for source color using (Bitmap copy = (Bitmap)bmp.Clone()) { for (int y = 0; y < height; y++) { for (int x = 0; x < width; x++) { // Adds a simple wave int newX = (int)(x + (distort * Math.Sin(Math.PI * y / 84.0))); int newY = (int)(y + (distort * Math.Cos(Math.PI * x / 44.0))); if (newX < 0 \|\| newX >= width) newX = 0; if (newY < 0 \|\| newY >= height) newY = 0; bmp.SetPixel(x, y, copy.GetPixel(newX, newY)); } } } return bmp; } private Brush GetBrush(Random rnd) { Brush brush = Brushes.Black; int ir = rnd.Next(9); switch (ir) { case 0: brush = Brushes.DarkCyan; break; case 1: brush = Brushes.DarkGreen; break; case 2: brush = Brushes.Crimson; break; case 3: brush = Brushes.DarkViolet; break; case 4: brush = Brushes.DarkOliveGreen; break; case 5: brush = Brushes.DarkOrchid; break; case 6: brush = Brushes.DarkTurquoise; break; } return brush; } private Font GetFont(Random rnd) { float sz = 15 + rnd.Next(4); Font f = new Font("Arial", sz); int i = rnd.Next(4); switch(i) { case 0: f = new Font("Tahoma", sz, FontStyle.Bold);break; case 1: f = new Font("Verdana", sz, FontStyle.Bold); break; case 2: f = new Font("Times New Roman", sz, FontStyle.Bold); break; } return f; } private void Drawing(Graphics gr, string s, PointF p, Random rnd) { float x = p.X; float y = p.Y; char [] c = s.ToCharArray(); for (int i = 0; i < c.Length; i++) { string ch = c [ i ] .ToString(); Brush brush = GetBrush(rnd); Font font = GetFont(rnd); SizeF sf = gr.MeasureString(ch, font); gr.DrawString(ch, font, brush, new PointF(x, y + (rnd.Next(7) - 3))); x = x + sf.Width / 2; } } private Pen GetPen(Random rnd) { Pen p = Pens.Black; int i = rnd.Next(4); switch (i) { case 0: p = Pens.Crimson; break; case 1: p = Pens.DarkCyan; break; case 2: p = Pens.DarkOliveGreen; break; } return p; } protected void Page_Load(object sender, EventArgs e) { Random rnd = new Random(); string captcha = Guid.NewGuid().ToString("N").Substring(0, 5); Session ["CAPTCHA"] = captcha; int wid = 100; int hei = 40; PointF p = new PointF(10 + rnd.Next(14), 4 + rnd.Next(2)); Bitmap bmp = new Bitmap(wid, hei); Graphics gr = Graphics.FromImage(bmp); System.Drawing.Rectangle rec = new Rectangle(0, 0, wid, hei); gr.FillRectangle(Brushes.White, rec); Drawing(gr, captcha, p, rnd); //bmp = TransformImage(bmp, rnd); int max = rnd.Next(2); for (int i = 0; i < 2 + max; i++) { Pen pen = GetPen(rnd); Point p1 = new Point(rnd.Next(wid), rnd.Next(hei)); Point p2 = new Point(rnd.Next(wid), rnd.Next(hei)); gr.DrawLine(pen, p1, p2); } Response.ContentType = "image/jpeg"; Response.Clear(); bmp.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg); bmp.Dispose(); Response.Flush(); Response.End(); } } }
tieuphu Thống chế Erich von Manstein 50 bài	30-05-2009 02:35:24 http://coder.awas.vn/downloads.ashx?id=72a215c9ff644b36a4641ff58812e603 code đây thưa bà con! --- Miệt mài, miệt mài ... http://awas.vn
qqqqq 2 bài	18-12-2010 10:59:25 Thanks nhieu nha !!!!!!!!!!!!!!!!!!!!!!!!

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