近日铁路订票网[12306]又出现多道另类考题，竟要订票者在8个图案中[点击图中所有美男子]、[请点击下图中所有的非智能眼镜]、[请点击下图中所有的博斯普鲁斯海峡]，网友吐槽：比高考题还难，到底是什么样子的，先跟大家分享一下几个例子：
哈哈，是有点奇葩的验证码，怪不得有人会说[妈妈我已经找不到回家]，这让分秒必争的春运网上抢票者瞬间傻眼，九成网友已经被打败……
正巧小编最近也在研究验证码，参考了许多网上案例，整理了一篇文章特分享给大家。
验证码的一般编写思路为：
1.定义验证码字符长度;
2.根据长度随机生成验证码字符串;
3.将验证码字符串转换成图片形式，并在图片中生成随机噪声点和声线（对验证码进行模糊识别处理）;
4.显示结果。
///
/// 生成随机验证码
///
/// 验证码长度
///
public string CreateIdentifyingCode( int CodeLen)
{
if (CodeLen < 1)
return String.Empty;
int num;
string checkcode = String.Empty;
Random random = new Random();
for ( int index = 0; index < CodeLen; index++)
{
num = random.Next();
if (num % 2 == 0)
checkcode += ( char )( '0' + ( char )(num % 10));
else
checkcode += ( char )( 'A' + ( char )(num % 26));
}
return checkcode;
}
-------------------------------------------------------------------------------------------------
///
/// 生成验证码图片
///
///
///
private void CreateCheckCodeImage( string checkcode)
{
if (checkcode == null || checkcode.Trim() == String.Empty)
return ;
//创建图片大小
System.Drawing.Bitmap image = new System.Drawing.Bitmap(( int )Math.Ceiling(checkcode.Length*12.5),22);
//创建画板
Graphics graphic = Graphics.FromImage(image);
try
{
Random random = new Random();
graphic.Clear(Color.White);
int x1 = 0, y1 = 0, x2 = 0, y2 = 0;
//画图片背景噪声线
for ( int index = 0; index < 25; index++)
{
x1 = random.Next(image.Width);
y1 = random.Next(image.Height);
x2 = random.Next(image.Width);
y2 = random.Next(image.Height);
graphic.DrawLine( new Pen(Color.Silver),x1,y1,x2,y2);
}
Font font = new System.Drawing.Font( "Helvetica" , 12, (FontStyle.Bold |FontStyle.Italic));
LinearGradientBrush brush = new LinearGradientBrush( new Rectangle(0, 0, image.Width, image.Height),Color.Blue,Color.DarkBlue,1.2f, true );
graphic.DrawString(checkcode,font,brush,2,2);
int x = 0;
int y = 0;
// 画图片的前景噪声点
for ( int index = 0; index < 100; index++)
{
x = random.Next(image.Width);
y = random.Next(image.Height);
image.SetPixel(x,y,Color.FromArgb(random.Next()));
}
//画图片的边框线
graphic.DrawRectangle( new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
//网页响应
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms,System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif" ;
Response.BinaryWrite(ms.ToArray());
}
finally
{
graphic.Dispose();
image.Dispose();
}
}
以上所生成的为简单的验证码。接下来我从其他的博客中学习了其他形式的效果。
/* 图片画线特殊效果：贝塞尔曲线 */
Graphics graph = Graphics.FromImage(image);
graph.Clear(Color.WhiteSmoke);
Point[] myArray ={
new Point(random.Next(150),random.Next(50)),
new Point(random.Next(150),random.Next(50)),
new Point(random.Next(150),random.Next(50)),
new Point(random.Next(150),random.Next(50)),
new Point(random.Next(150),random.Next(50)),
new Point(random.Next(150),random.Next(50)),
new Point(random.Next(150),random.Next(50)),
new Point(random.Next(150),random.Next(50)),
new Point(random.Next(150),random.Next(50)),
new Point(random.Next(150),random.Next(50))
};
Pen myPen = new Pen(Color.Blue, 1);
GraphicsPath myPath = new GraphicsPath();
myPath.AddBeziers(myArray);
graph.DrawPath(myPen, myPath);
验证码字符颜色变换效果 ：实现该效果，我们首先来定义一个颜色集合，然后通过 for循环使其随机改变字体颜色 则可。
#region 定义颜色数组
Color[] colors = { Color.Blue, Color.Green, Color.Red, Color.Gold, Color.Black, Color.Chocolate, Color.Orange, Color.Purple };
public Color[] Colors
{
get { return colors; }
set { colors = value; }
}
#endregion
Brush brush;
int colornum;
for ( int i=0; i
{
colornum = random.Next(Colors.Length - 1);
brush = new System.Drawing.SolidBrush(Colors[cindex]);
//利用DrawString函数进行颜色填充就可以了。
}
同样的原理我们也可以定义一个字体的数组来进行验证码字体切换。代码和颜色的类似，这里就不加以累赘。
接下来看看如何使得验证码的字体进行扭曲。
private const double PI = 3.1415926535897932384626433832795;
private const double PI2 = 6.283185307179586476925286766559;
///
/// 波形滤镜效果函数
///
///
///
///
///
///
public System.Drawing.Bitmap TwistImage(Bitmap srcbmp, double dmultvalue, double dphase)
{
System.Drawing.Bitmap destbmp = new Bitmap(srcbmp.Width,srcbmp.Height);
System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destbmp);
//填充背景图为白色
graph.FillRectangle( new SolidBrush(System.Drawing.Color.White), 0, 0, destbmp.Width, destbmp.Height);
graph.Dispose();
double dbaselen = ( double )destbmp.Width;
for ( int i = 0; i < destbmp.Width; i++)
{
for ( int j = 0; j < destbmp.Height; j++)
{
double dx = 0;
dx = (PI2 * ( double )j) / dbaselen;
dx += dphase;
double dy = Math.Sin(dx);
int noldx = 0, noldy = 0;
noldx = i + ( int )(dy * dmultvalue);
noldy = 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;
}
上面代码是参考了这段代码进行的学习<C#.net 好用的验证码代码 汉字-变色-扭曲-波动 >，代码如下
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Drawing;
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;
public partial class study_CheckCode2 : System.Web.UI.Page
{
protected void Page_Load( object sender, EventArgs e)
{
string code = CreateVerifyCode(); //取随机码
CreateImageOnPage(code, this .Context); // 输出图片
Response.Cookies.Add( new HttpCookie( "CheckCode" , code.ToUpper())); // 使用Cookies取验证码的值
}
#region 验证码长度(默认4个验证码的长度)
int length = 4;
public int Length
{
get { return length; }
set { length = value; }
}
#endregion
#region 验证码字体大小(为了显示扭曲效果，默认40像素，可以自行修改)
int fontSize = 40;
public int FontSize
{
get { return fontSize; }
set { fontSize = value; }
}
#endregion
#region 边框补(默认1像素)
int padding = 2;
public int Padding
{
get { return padding; }
set { padding = value; }
}
#endregion
#region 是否输出燥点(默认不输出)
bool chaos = true ;
public bool Chaos
{
get { return chaos; }
set { chaos = value; }
}
#endregion
#region 输出燥点的颜色(默认灰色)
Color chaosColor = Color.LightGray;
public Color ChaosColor
{
get { return chaosColor; }
set { chaosColor = value; }
}
#endregion
#region 自定义背景色(默认白色)
Color backgroundColor = Color.White;
public Color BackgroundColor
{
get { return backgroundColor; }
set { backgroundColor = value; }
}
#endregion
#region 自定义随机颜色数组
Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
public Color[] Colors
{
get { return colors; }
set { colors = value; }
}
#endregion
#region 自定义字体数组
string [] fonts = { "Arial" , "Georgia" };
public string [] Fonts
{
get { return fonts; }
set { fonts = value; }
}
#endregion
#region 自定义随机码字符串序列(使用逗号分隔)
//string codeSerial = "0,1,2,3,4,5,6,7,8,9,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,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";
string codeSerial = "阿,保,持,的,法,规,和,东,三,省,问,我,惹,你,诶,没,改,变,揍,屁,股,吧" ;
public string CodeSerial
{
get { return codeSerial; }
set { codeSerial = value; }
}
#endregion
#region 产生波形滤镜效果
private const double PI = 3.1415926535897932384626433832795;
private const double PI2 = 6.283185307179586476925286766559;
/// <summary>
/// 正弦曲线Wave扭曲图片（Edit By 51aspx.com）
/// </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>
/// <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 ? (PI2 * ( double )j) / dBaseAxisLen : (PI2 * ( 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;
}
#endregion
#region 生成校验码图片
public Bitmap CreateImageCode( string code)
{
int fSize = FontSize;
int fWidth = fSize + Padding;
int imageWidth = ( int )(code.Length * fWidth) + 30 + Padding * 2;
int imageHeight = fSize * 2 + Padding;
System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight);
Graphics g = Graphics.FromImage(image);
g.Clear(BackgroundColor);
Random rand = new Random();
//给背景添加随机生成的燥点
if ( this .Chaos)
{
Pen pen = new Pen(ChaosColor, 0);
int c = Length * 10;
for ( int i = 0; i < c; i++)
{
int x = rand.Next(image.Width);
int y = rand.Next(image.Height);
g.DrawRectangle(pen, x, y, 1, 1);
}
}
int left = 0, top = 0, top1 = 1, top2 = 1;
int n1 = (imageHeight - FontSize - Padding * 2);
int n2 = n1 / 4;
top1 = n2;
top2 = n2 * 2;
Font f;
Brush b;
int cindex, findex;
//随机字体和颜色的验证码字符
for ( int i = 0; i < code.Length; i++)
{
cindex = rand.Next(Colors.Length - 1);
findex = rand.Next(Fonts.Length - 1);
f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
b = new System.Drawing.SolidBrush(Colors[cindex]);
if (i % 2 == 1)
{
top = top2;
}
else
{
top = top1;
}
left = i * fWidth;
g.DrawString(code.Substring(i, 1), f, b, left, top);
}
//画一个边框 边框颜色为Color.Gainsboro
g.DrawRectangle( new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);
g.Dispose();
//产生波形（Add By 51aspx.com）
image = TwistImage(image, true , 8, 4);
return image;
}
#endregion
#region 将创建好的图片输出到页面
public void CreateImageOnPage( string code, HttpContext context)
{
System.IO.MemoryStream ms = new System.IO.MemoryStream();
Bitmap image = this .CreateImageCode(code);
image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
context.Response.ClearContent();
context.Response.ContentType = "image/Jpeg" ;
context.Response.BinaryWrite(ms.GetBuffer());
ms.Close();
ms = null ;
image.Dispose();
image = null ;
}
#endregion
#region 生成随机字符码
public string CreateVerifyCode( int codeLen)
{
if (codeLen == 0)
{
codeLen = Length;
}
string [] arr = CodeSerial.Split( ',' );
string code = "" ;
int randValue = -1;
Random rand = new Random( unchecked (( int )DateTime.Now.Ticks));
for ( int i = 0; i < codeLen; i++)
{
randValue = rand.Next(0, arr.Length - 1);
code += arr[randValue];
}
return code;
}
public string CreateVerifyCode()
{
return CreateVerifyCode(0);
}
#endregion
}
一年一度的抢票热潮又开始了，希望大家都能顺利买到回家的火车篇，回家过年，突然感觉有点年味了，一年又一年，时间都去哪了，小小的感慨一下……
言归正传，这就是为大家分享的C#验证码程序，和12306验证码差多了，不过也是小编的学习收获吧！大家也可以结合下面这两篇文章进行学习：
《12306动态验证码启发之ASP.NET实现动态GIF验证码(附源码)》
《12306验证码破解思路分享》
希望本文所述对大家学习验证码技术有所帮助。
dy("nrwz");
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