图片验证码
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");
}
}
}
}
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