生成图片验证码
自己写了一个验证码图片生成的页面
效果如下：
主要实现效果
- 随机渐变背景
- 随机字体颜色（渐变）、大小、角度、扭曲
- 随机干扰曲线
代码如下：
1、先写一个类（字符串生成器）
using System; using System.Collections.Generic; using System.Linq; using System.Threading; using System.Web; namespace Lian.Model { /// <summary> ////// </summary> public class StringGenerator { /// <summary> /// create a random key /// </summary> static readonly Random Random = new Random(~unchecked((int)DateTime.Now.Ticks)); static readonly char[] NumberList = { '1', '2', '3', '4', '5', '6', '7', '8', '9' }; static readonly char[] CharList = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' }; static readonly char[] MixedList = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' }; //remove I & O /// <summary> /// 生成随机数字 /// </summary> /// <param name="Length">生成长度</param> public static string Number(int Length) { return Create(Length, false, NumberList); } /// <summary> /// 生成随机字母与数字 /// </summary> /// <param name="Length">生成长度</param> public static string Mixed(int Length) { return Create(Length, false, MixedList); } /// <summary> /// 生成随机纯字母随机数 /// </summary> /// <param name="Length">生成长度</param> public static string Char(int Length) { return Create(Length, false, CharList); } /// <summary> /// 指定字符串长度、线程休眠、字符列表，创建验证码 /// </summary> /// <param name="Length">Length.</param> /// <param name="Sleep">If set to <c>true</c> sleep.</param> /// <param name="List">List create CAPTCHA based on</param> /// <returns>The create.</returns> private static string Create(int Length, bool Sleep, char[] List) { if (Sleep) Thread.Sleep(3); char[] Pattern = List; string result = string.Empty; int n = Pattern.Length; for (int i = 0; i < Length; i++) { int rnd = Random.Next(0, n); result += Pattern[rnd]; } return result; } } }
2、再写一个类（生成图片）
using System; using System.Collections.Generic; using System.Drawing; using System.Linq; using System.Threading; using System.Web; namespace Lian.Model { public class CaptchaGenerator { #region 私有字段 public string Text { get; private set; } public Bitmap Image { get; private set; } private int LetterCount { set; get; } // 验证码位数 private int Type { set; get; } private int letterWidth = 16; // 单个字体的宽度范围 private int letterHeight = 20; // 单个字体的高度范围 private static Random Random = new Random(~unchecked((int)DateTime.Now.Ticks)); private Font[] fonts = { new Font(new FontFamily("Times New Roman"),10 + Random.Next(1),FontStyle.Regular), new Font(new FontFamily("Georgia"), 10 + Random.Next(1),FontStyle.Regular), new Font(new FontFamily("Arial"), 10 + Random.Next(1),FontStyle.Regular), new Font(new FontFamily("Comic Sans MS"), 10 + Random.Next(1),FontStyle.Regular) }; #endregion #region 构造器 /// <summary> /// 实例化 <see cref="T:AiXiu.Common.CaptchaGenerator"/> 类的一个新实例，默认为4个数字长度 /// </summary> public CaptchaGenerator() { //HttpContext.Current.Response.Expires = 0; //HttpContext.Current.Response.Buffer = true; //HttpContext.Current.Response.ExpiresAbsolute = DateTime.Now.AddSeconds(-1); //HttpContext.Current.Response.AddHeader("pragma", "no-cache"); //HttpContext.Current.Response.CacheControl = "no-cache"; LetterCount = 4; Type = 0; InitText(); CreateImage(); } /// <summary> /// 指定数字长度实例化 <see cref="T:AiXiu.Common.CaptchaGenerator"/> 类的一个新实例 /// </summary> /// <param name="Length">Length.</param> public CaptchaGenerator(int Length) { //HttpContext.Current.Response.Expires = 0; //HttpContext.Current.Response.Buffer = true; //HttpContext.Current.Response.ExpiresAbsolute = DateTime.Now.AddSeconds(-1); //HttpContext.Current.Response.AddHeader("pragma", "no-cache"); //HttpContext.Current.Response.CacheControl = "no-cache"; LetterCount = Length; Text = StringGenerator.Number(LetterCount); CreateImage(); } /// <summary> /// 实例化 <see cref="T:AiXiu.Common.CaptchaGenerator"/> 类的一个新实例 /// </summary> /// <param name="Length">Length.</param> /// <param name="type">Type 0 number , 1 char , 2 mixed.</param> public CaptchaGenerator(int Length, int type) { //HttpContext.Current.Response.Expires = 0; //HttpContext.Current.Response.Buffer = true; //HttpContext.Current.Response.ExpiresAbsolute = DateTime.Now.AddSeconds(-1); //HttpContext.Current.Response.AddHeader("pragma", "no-cache"); //HttpContext.Current.Response.CacheControl = "no-cache"; LetterCount = Length; Type = type; InitText(); CreateImage(); } #endregion #region 私有方法 /// <summary> /// 初始化文本 /// </summary> private void InitText() { switch (Type) { case 0: Text = StringGenerator.Number(LetterCount); break; case 1: Text = StringGenerator.Char(LetterCount); break; case 2: Text = StringGenerator.Mixed(LetterCount); break; default: break; } } /// <summary> /// 绘制验证码 /// </summary> private void CreateImage() { int ImageWidth = this.Text.Length * letterWidth; Bitmap Img = new Bitmap(ImageWidth, letterHeight); Graphics g = Graphics.FromImage(Img); g.Clear(Color.White); for (int i = 0; i < 2; i++) { int x1 = Random.Next(Img.Width - 1); int x2 = Random.Next(Img.Width - 1); int y1 = Random.Next(Img.Height - 1); int y2 = Random.Next(Img.Height - 1); g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2); } int _x = -12, _y; for (int int_index = 0; int_index < this.Text.Length; int_index++) { _x += Random.Next(12, 16); _y = Random.Next(-2, 2); string str_char = this.Text.Substring(int_index, 1); str_char = Random.Next(1) == 1 ? str_char.ToLower() : str_char.ToUpper(); Brush newBrush = new SolidBrush(GetRandomColor()); Point thePos = new Point(_x, _y); g.DrawString(str_char, fonts[Random.Next(fonts.Length - 1)], newBrush, thePos); } for (int i = 0; i < 10; i++) { int x = Random.Next(Img.Width - 1); int y = Random.Next(Img.Height - 1); Img.SetPixel(x, y, Color.FromArgb(Random.Next(0, 255), Random.Next(0, 255), Random.Next(0, 255))); } Img = TwistImage(Img, true, Random.Next(1, 3), Random.Next(4, 6)); g.DrawRectangle(new Pen(Color.LightGray, 1), 0, 0, ImageWidth - 1, (letterHeight - 1)); Image = Img; } /// <summary> /// 字体随机颜色 /// </summary> private Color GetRandomColor() { Random RandomNum_First = new Random((int)DateTime.Now.Ticks); Thread.Sleep(RandomNum_First.Next(50)); Random RandomNum_Sencond = new Random((int)DateTime.Now.Ticks); int int_Red = RandomNum_First.Next(180); int int_Green = RandomNum_Sencond.Next(180); int int_Blue = (int_Red + int_Green > 300) ? 0 : 400 - int_Red - int_Green; int_Blue = (int_Blue > 255) ? 255 : int_Blue; return Color.FromArgb(int_Red, int_Green, int_Blue); } /// <summary> /// 正弦曲线Wave扭曲图片 /// </summary> /// <param name="srcBmp">图片路径</param> /// <param name="bXDir">如果扭曲则选择为True</param> /// <param name="dMultValue">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> private Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase) { double PI = 6.283185307179586476925286766559; Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height); Graphics graph = Graphics.FromImage(destBmp); graph.FillRectangle(new SolidBrush(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; dx = bXDir ? (PI * (double)j) / dBaseAxisLen : (PI * (double)i) / dBaseAxisLen; dx += dPhase; double dy = Math.Sin(dx); int nOldX = 0, nOldY = 0; nOldX = bXDir ? i + (int)(dy * dMultValue) : i; nOldY = bXDir ? j : j + (int)(dy * dMultValue); Color color = srcBmp.GetPixel(i, j); if (nOldX >= 0 && nOldX < destBmp.Width && nOldY >= 0 && nOldY < destBmp.Height) { destBmp.SetPixel(nOldX, nOldY, color); } } } srcBmp.Dispose(); return destBmp; } #endregion } }
3、前台
<body> <form id="form1" runat="server"> <div> <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> <img src="yiban/CaptchaHandler.ashx" class="captcha" /> <a class="PictureIma">看不清？换一张</a> <asp:Button ID="Button1" runat="server" Text="验证" OnClick="Button1_Click" /> </div> </form> </body> <script src="Scripts/jquery-3.4.1.min.js"></script> <script type="text/javascript"> // 图形验证码点击刷新 var captcha = $(".captcha"); var captchaSrc = captcha.attr('src') captcha.on('click', function () { $(this).attr('src', captchaSrc + '?r=' + Math.random()); }) $(".PictureIma").click(function () { $(this).attr('src', captchaSrc + '?r=' + Math.random()); }) </script>
4、一般处理程序
using Lian.Model; using System; using System.Collections.Generic; using System.Linq; using System.Runtime.Remoting.Contexts; using System.Web; using System.Web.SessionState; namespace Lian.yiban { /// <summary> /// CaptchaHandler 的摘要说明 /// </summary> public class CaptchaHandler : IHttpHandler,IRequiresSessionState { public void ProcessRequest(HttpContext context) { CaptchaGenerator captcha = new CaptchaGenerator(4, 2); context.Session["code"] = captcha.Text;/*拿到验证码*/ var a = context.Session["code"]; //context.Session.Add("code", captcha.Text); //图片 captcha.Image.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg); context.Response.ContentType = "image/Jpeg"; context.Response.End(); } public bool IsReusable { get { return false; } } } }
5、后台代码
using System; using System.Collections.Generic; using System.Drawing; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using Lian.Model; using Lian.yiban; //using System.Web.SessionState; namespace Lian { public partial class WebForm3 : System.Web.UI.Page//, IReadOnlySessionState { protected void Page_Load(object sender, EventArgs e) { } protected void Button1_Click(object sender, EventArgs e) { if (Page.IsValid) { var aa = Session["code"]; var bb = TextBox1.Text; if (Session["code"].Equals(bb)) { Console.WriteLine("成功"); } Console.WriteLine("失败"); } } } }
