验证码的制作
www.diybl.com 时间 ： 2008-03-24 作者：佚名 编辑：本站 点击： [ 评论 ]
C#用的是GDI+,还没深入学习,下面代码是根据书上和网上的资料写的,仿GOOGLE的扭曲验证码
using System;using System.Data;using System.Configuration;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using System.Drawing;public partial class _Default : System.Web.UI.Page
...{
protected void Page_Load(object sender, EventArgs e)
...{ String validateCode = GenerateCode(); System.Drawing.Bitmap image = new Bitmap((int)Math.Ceiling((validateCode.Length * 17.0)), 30); Graphics g = Graphics.FromImage(image); try ...{ Random random = new Random(); g.Clear(Color.White); Font font = new System.Drawing.Font("Arial", 14, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic)); System.Drawing.Drawing2D.LinearGradientBrush brush; for (int i = 0; i < validateCode.Length; i++) ...{ brush = new System.Drawing.Drawing2D.LinearGradientBrush (new Rectangle(0, 0, image.Width, image.Height), Color.FromArgb(random.Next(255), random.Next(255), random.Next(255)) , Color.FromArgb(random.Next(255), random.Next(255), random.Next(255)), 1.2f, true); g.DrawString(validateCode.Substring(i, 1), font, brush, 1 + 16 * i, 2);
} g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); System.IO.MemoryStream ms = new System.IO.MemoryStream(); image = TwistImage(image, true, 4, random.Next(5) + (double)random.Next(9) / 10.0 + (double)random.Next(9) / 100.0); image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); Response.ClearContent(); Response.ContentType = "image/Gif"; Response.BinaryWrite(ms.ToArray()); } finally ...{ g.Dispose(); image.Dispose(); } } protected String GenerateCode() ...{ int number; char code; String validateCode = ""; Random random = new Random(); int length = random.Next(4, 7); for (int i = 0; i < length; i++) ...{ number = random.Next(); if (number % 3 == 0) code = (char)(''1'' + (char)(number % 9)); else if (number % 3 == 1) code = (char)(''A'' + (char)(number % 26)); else code = (char)(''a'' + (char)(number % 26)); validateCode += code.ToString(); } Session["validateCode"] = validateCode; return validateCode; } // <param name="srcBmp">图片路径</param> // <param name="bXDir">如果扭曲则选择为True</param> // <param name="nMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param> // <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param> // <returns></returns> public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase) ...{ System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height); // 将位图背景填充为白色 System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp); graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height); graph.Dispose(); double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width; for (int i = 0; i < destBmp.Width; i++) ...{ for (int j = 0; j < destBmp.Height; j++) ...{ double dx = 0; dx = bXDir ? (3.1415926 * 2 * (double)j) / dBaseAxisLen : (3.1415926 * 2 * (double)i) / dBaseAxisLen; dx += dPhase; double dy = Math.Sin(dx); // 取得当前点的颜色 int nOldX = 0, nOldY = 0; nOldX = bXDir ? i + (int)(dy * dMultValue) : i; nOldY = bXDir ? j : j + (int)(dy * dMultValue); System.Drawing.Color color = srcBmp.GetPixel(i, j); if (nOldX >= 0 && nOldX < destBmp.Width && nOldY >= 0 && nOldY < destBmp.Height) ...{ destBmp.SetPixel(nOldX, nOldY, color); } } } return destBmp; }
}效果:
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