/// <summary>
/// 验证码类
/// </summary>
public static class StringCAPTCHA
{
/// <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
#region 生成随机数字
/// <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>
/// 生成随机数字
/// </summary>
/// <param name="Length">生成长度</param>
/// <param name="Sleep">是否要在生成前将当前线程阻止以避免重复</param>
public static string Number(int Length, bool Sleep)
{
return Create(Length, Sleep, NumberList);
}
#endregion
#region 生成随机字母与数字
/// <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>
/// 生成随机字母与数字
/// </summary>
/// <param name="Length">生成长度</param>
/// <param name="Sleep">是否要在生成前将当前线程阻止以避免重复</param>
public static string Mixed(int Length, bool Sleep)
{
return Create(Length, Sleep, MixedList);
}
#endregion
#region 生成随机纯字母随机数
/// <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>
/// 生成随机纯字母随机数
/// </summary>
/// <param name="Length">生成长度</param>
/// <param name="Sleep">是否要在生成前将当前线程阻止以避免重复</param>
public static string Char(int Length, bool Sleep)
{
return Create(Length, Sleep, CharList);
}
#endregion
/// <summary>
/// Create the CAPTCHA specified Length, Sleep and List.
/// </summary>
/// <returns>The create.</returns>
/// <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>
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;
}
}
/// <summary>
/// 验证图片类
/// </summary>
public class PictureCAPTCHA
{
#region 私有字段
private string text { get; set; }
private Bitmap image { get; 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 公有属性
/// <summary>
/// 验证码
/// </summary>
public string Text
{
get { return this.text; }
}
/// <summary>
/// 验证码图片
/// </summary>
public Bitmap Image
{
get { return this.image; }
}
#endregion
#region constructor
/// <summary>
/// Initializes a new instance of the <see cref="T:DotNet.Utilities.PictureCAPTCHA"/> class. default length is 4 with number list
/// </summary>
public PictureCAPTCHA()
{
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>
/// Initializes a new instance of the <see cref="T:DotNet.Utilities.PictureCAPTCHA"/> class with number list;
/// </summary>
/// <param name="Length">Length.</param>
public PictureCAPTCHA(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 = StringCAPTCHA.Number(LetterCount);
CreateImage();
}
/// <summary>
/// Initializes a new instance of the <see cref="T:DotNet.Utilities.PictureCAPTCHA"/> class.
/// </summary>
/// <param name="Length">Length.</param>
/// <param name="type">Type 0 number , 1 char , 2 mixed.</param>
public PictureCAPTCHA(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 Public function
public void Redraw(bool NewCAPTCHA)
{
if (NewCAPTCHA)
{
InitText();
}
CreateImage();
}
#endregion
#region private funcation
private void InitText()
{
switch (Type)
{
case 0: text = StringCAPTCHA.Number(LetterCount); break;
case 1: text = StringCAPTCHA.Char(LetterCount); break;
case 2: text = StringCAPTCHA.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 = 0;
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 = 0;
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
}
控制器代码
public ActionResult GetCaptcha()
{
PictureCAPTCHA cpa = new PictureCAPTCHA(4, 2);
using (MemoryStream stream = new MemoryStream())
{
cpa.Image.Save(stream, ImageFormat.Jpeg);
byte[] data = new byte[stream.Length];
stream.Seek(0, SeekOrigin.Begin);
stream.Read(data, 0, Convert.ToInt32(stream.Length));
SessionHelper.RemoveSession("captcha");
SessionHelper.SetSession("captcha", cpa.Text);
return File(data, "image / Jpeg");
}
}
HTML
<img class="capimg" src="/Home/GetCaptcha" />