空心字体验证码

来源：互联网发布：左小青陈道明知乎编辑：程序博客网时间：2024/05/10 16:17

<%@ WebHandler Language="C#" Class="Handler" %>

using System;
using System.Web;
using System.Drawing;
using System.Drawing.Imaging;
using System.Text;
using System.Web.SessionState;
using System.Drawing.Text;
using System.Drawing.Drawing2D;

public class Handler : IHttpHandler, IRequiresSessionState
{

static PrivateFontCollection pfc = null;
public void ProcessRequest(HttpContext context)
{
string checkCode = context.Request.QueryString["ValidateCode"];
if (checkCode == null)
checkCode = "0 0 0 0";
context.Session["GetCode"] = checkCode;
int iwidth = 108;//(int)(checkCode.Length * 11.5);
System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 45);
Graphics g = Graphics.FromImage(image);
Random random = new Random(System.DateTime.Now.Millisecond);




//Font f = new System.Drawing.Font("Arial", 16, System.Drawing.FontStyle.Regular);

//Brush b = new System.Drawing.SolidBrush(Color.Black);
Brush b = new System.Drawing.SolidBrush(Color.FromArgb(4683611));
//g.FillRectangle(new System.Drawing.SolidBrush(Color.Blue),0,0,image.Width, image.Height);
//Color color = Color.FromArgb(16775149);
g.Clear(Color.FromArgb(237, 247, 255));
using (StringFormat format = new StringFormat())
{

format.Alignment = StringAlignment.Center;
format.LineAlignment = StringAlignment.Center;
format.FormatFlags = StringFormatFlags.NoWrap;
Matrix matrix = new Matrix();
float offsetx = -35, offsety = 0;
g.SmoothingMode = SmoothingMode.AntiAlias;
for (int i = 0; i < checkCode.Length; i++)
{
int fsize = random.Next(24,28);
Font f = CreateFont(context.Server.MapPath("tt0767m_.TTF"), fsize, FontStyle.Bold, GraphicsUnit.Point, 0);
SizeF size = g.MeasureString(checkCode[i].ToString(), f);
matrix.RotateAt(random.Next(-15, 10), new PointF(offsetx+size.Width/2, offsety+size.Height/2));
g.Transform = matrix;

g.DrawString(
checkCode[i].ToString(),
f,
Brushes.Green,
new RectangleF(
offsetx,
offsety,
image.Width,
image.Height),
format);
//g.DrawString(checkCode, f, b, 3, 3);
offsetx += size.Width*3/5;
offsety += -0;
g.RotateTransform(0);
matrix.Reset();
f.Dispose();
}
}

Pen blackPen = new Pen(Color.Black, 0);
//Random rand = new Random();
//for (int i = 0; i < 5; i++)
//{
// int y = rand.Next(image.Height);
// g.DrawLine(blackPen, 0, y, image.Width, y);
//}
//System.Random rand = new Random();
//int num = image.Width * image.Height * 30 / 300;
//for (int iCount = 0; iCount < num; iCount++)
//{
// int x = rand.Next(image.Width);
// int y = rand.Next(image.Height);
// int r = rand.Next(255);
// int h = rand.Next(255);
// int k = rand.Next(255);
// Color c = Color.FromArgb(r, h, k);
// image.SetPixel(x, y, c);
//}
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
context.Response.ClearContent();
context.Response.ContentType = "image/Jpeg";
context.Response.BinaryWrite(ms.ToArray());
g.Dispose();
image.Dispose();
}
protected void DrawChar(char[] randChar, Graphics g, Bitmap bmp, Font _font)
{
Random random = new Random(6);
//绘制字符
for (int i = 0; i < randChar.Length; i++)
{
//获取显示的单个文字所占空间
SizeF size = g.MeasureString(randChar[i].ToString(), _font);

Point p = new Point(i * (int)(bmp.Width * 0.9) / randChar.Length + random.Next(-3, 3), 2 + random.Next(-2, 2));
System.Drawing.Drawing2D.Matrix transform = new System.Drawing.Drawing2D.Matrix();
//沿着单个文字的中心旋转旋转一个随机的角度 0~30度
transform.RotateAt(random.Next(0, 30), new PointF(p.X + size.Width / 2, p.Y + size.Height / 2));
//更改矩阵
g.Transform = transform;
g.DrawString(randChar[i].ToString(), _font, new SolidBrush(Color.FromArgb(random.Next(0, 256), random.Next(0, 256), random.Next(0, 256))), p);
//矩阵还原
g.RotateTransform(0);
}
}
public static Font CreateFont(string fontFile, float fontSize, FontStyle fontStyle, GraphicsUnit graphicsUnit, byte gdiCharSet)

{

/*PrivateFontCollection 类允许应用程序安装现有字体的私有版本，而无需替换该字体的系统版本。例如，除系统使用的 Arial 字体外，GDI+ 还可以创建 Arial 字体的私有版本。PrivateFontCollection 还可以用于安装操作系统中不存在的字体。这种临时的字体安装不会影响系统安装的字体集合。若要查看已安装的字体集合，请使用InstalledFontCollection 类。*/

pfc = new PrivateFontCollection();
pfc.AddFontFile(fontFile);
return new Font(pfc.Families[0], fontSize, fontStyle, graphicsUnit, gdiCharSet);
}
private string CreateRandomCode(int codeCount)
{
string allChar = "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,W,X,Y,Z";
//string allChar = "0,1,2,3,4,5,6,7,8,9";
string[] allCharArray = allChar.Split(',');
string randomCode = "";
int temp = -1;

Random rand = new Random();
for (int i = 0; i < codeCount; i++)
{
if (temp != -1)
{
rand = new Random(i * temp * ((int)DateTime.Now.Ticks));
}
int t = rand.Next(allChar.Length);
if (temp == t)
{
return CreateRandomCode(codeCount);
}
temp = t;
randomCode += allCharArray[t] + " ";
}
return randomCode;
}
public bool IsReusable
{
get
{
return true;
}
}

}

前端测试代码:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>CAPTCHA Example</title>
<script type="text/javascript" language="javascript" src="/Scripts/jquery-1.4.1.min.js"></script>

<style type="text/css">
body {
font-size:12px;
font-family:Verdana, Arial, Helvetica, sans-serif;
}
</style>

<script language="javascript" type="text/javascript">
//var allChar = ['0','1','2','3','4','5','6','7','8','9'];
var allChar = ["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","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","W","X","Y","Z"];
//var allChar = new Array("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","W","X","Y","Z");

//var allChar = new Array('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','W','X','Y','Z');
function TestCaptcha()
{
var formcode = document.getElementById("captchacode");
var sessioncode = document.getElementById("validatecode");

if(formcode.value.toLowerCase() == sessioncode.value.toLowerCase())
return true;
else
{
$("#msg").css("display","inline");
$("#msg").html("验证码错误");
RefreshImage("img1");
return false;
}
}
function fRandomBy(under, over){
switch(arguments.length){
case 1: return parseInt(Math.random()*under+1);
case 2: return parseInt(Math.random()*(over-under+1) + under);
default: return 0;
}
}
function CreateCode2()
{
var i, ret, hvalue,tmp, num, result;
ret="";
hvalue=""

//随机生成3个或4个验证码
result=parseInt(Math.random()*10) % 2;
if(result == 1)
{
num=3;
}
else
{
num = 4;
}
for(i=0;i<num;i++)
{
tmp=fRandomBy(allChar.length-1);
hvalue= hvalue+allChar[tmp];
ret = ret + allChar[tmp];
}
var formcode = document.getElementById("validatecode");
formcode.value= hvalue;
return ret;
}

function CreateCode(num)
{
var i, ret, hvalue,tmp;
ret="";
hvalue=""
for(i=0;i<num;i++)
{
tmp=fRandomBy(9);
hvalue= hvalue+tmp;
ret = ret + tmp+ " ";
}
var formcode = document.getElementById("validatecode");
formcode.value= hvalue;
return ret;
}
function RefreshImage(valImageId) {
var objImage = document.images[valImageId];
if (objImage == undefined) {
return;
}
var code = CreateCode2();

objImage.src = objImage.src.split('?')[0] + '?ValidateCode=' + code;
}
$(document).ready(function(){
var objImage = document.images["img1"];
if(objImage == undefined)
{
return;
}
var code = CreateCode2();
objImage.src = objImage.src.split('?')[0] + '?ValidateCode=' + code;
});
</script>

</head>
<body>
<form id="form1" name="form1" method="post" action="default.aspx" onsubmit="return TestCaptcha();" >
<table width="400" border="1" align="center">
<tr>
<td colspan="2" align="center">
<strong>CAPTCHA Example</strong></td>
</tr>
<tr>
<td id="msg" colspan="2" align="right" style=" background-color:#fff2f2;height:20px ">
</td>
</tr>
<tr>
<td width="261">
CAPTCHA Image
<input name="abc" type="text" id="abc" /></td>
<td width="223">

<img alt="" id="img1" src="Handler2.ashx?ValidateCode=1234" /><a href="javascript:void(0)"
onclick="RefreshImage('img1')">Change Image</a><br />
</td>
</tr>
<tr>
<td>
Write the characters in the image above</td>
<td>
<input name="captchacode" type="text" id="captchacode" size="10" /></td>
</tr>
<tr>
<td> 
</td>
<td>
<input type="submit" name="btnTest" id="btnTest" value="Test Input" />
</td>
</tr>
</table>
<input type="hidden" id="validatecode" />
</form>
</body>
</html>