///////////////////////CaptchaImage.cs//////////////
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Drawing.Text;
namespace CaptchaImage
{
public class CaptchaImage
{
public string Text
{
get { return this.text; }
}
public Bitmap Image
{
get { return this.image; }
}
public int Width
{
get { return this.width; }
}
public int Height
{
get { return this.height; }
}
private string text;
private int width;
private int height;
private string familyName;
private Bitmap image;
private Random random = new Random();
public CaptchaImage(string s, int width, int height)
{
this.text = s;
this.SetDimensions(width, height);
this.GenerateImage();
}
public CaptchaImage(string s, int width, int height, string familyName)
{
this.text = s;
this.SetDimensions(width, height);
this.SetFamilyName(familyName);
this.GenerateImage();
}
~CaptchaImage()
{
Dispose(false);
}
public void Dispose()
{
GC.SuppressFinalize(this);
this.Dispose(true);
}
protected virtual void Dispose(bool disposing)
{
if (disposing)
this.image.Dispose();
}
private void SetDimensions(int width, int height)
{
if (width <= 0)
throw new ArgumentOutOfRangeException("width", width, "Argument out of range, must be greater than zero.");
if (height <= 0)
throw new ArgumentOutOfRangeException("height", height, "Argument out of range, must be greater than zero.");
this.width = width;
this.height = height;
}
private void SetFamilyName(string familyName)
{
try
{
Font font = new Font(this.familyName, 12F);
this.familyName = familyName;
font.Dispose();
}
catch (Exception ex)
{
this.familyName = System.Drawing.FontFamily.GenericSerif.Name;
}
}
private void GenerateImage()
{
Bitmap bitmap = new Bitmap(this.width, this.height, PixelFormat.Format32bppArgb);
Graphics g = Graphics.FromImage(bitmap);
g.SmoothingMode = SmoothingMode.AntiAlias;
Rectangle rect = new Rectangle(0, 0, this.width, this.height);
HatchBrush hatchBrush = new HatchBrush(HatchStyle.SmallConfetti, Color.LightGray, Color.White);
g.FillRectangle(hatchBrush, rect);
SizeF size;
float fontSize = rect.Height + 1;
Font font;
do
{
fontSize--;
font = new Font(this.familyName, fontSize, FontStyle.Bold);
size = g.MeasureString(this.text, font);
} while (size.Width > rect.Width);
StringFormat format = new StringFormat();
format.Alignment = StringAlignment.Center;
format.LineAlignment = StringAlignment.Center;
GraphicsPath path = new GraphicsPath();
path.AddString(this.text, font.FontFamily, (int) font.Style, font.Size, rect, format);
float v = 4F;
PointF[] points =
{
new PointF(this.random.Next(rect.Width) / v, this.random.Next(rect.Height) / v),
new PointF(rect.Width - this.random.Next(rect.Width) / v, this.random.Next(rect.Height) / v),
new PointF(this.random.Next(rect.Width) / v, rect.Height - this.random.Next(rect.Height) / v),
new PointF(rect.Width - this.random.Next(rect.Width) / v, rect.Height - this.random.Next(rect.Height) / v)
};
Matrix matrix = new Matrix();
matrix.Translate(0F, 0F);
path.Warp(points, rect, matrix, WarpMode.Perspective, 0F);
hatchBrush = new HatchBrush(HatchStyle.DarkDownwardDiagonal, Color.Gray, Color.DarkGray);
g.FillPath(hatchBrush, path);
int m = Math.Max(rect.Width, rect.Height);
for (int i = 0; i < (int) (rect.Width * rect.Height / 30F); i++)
{
int x = this.random.Next(rect.Width);
int y = this.random.Next(rect.Height);
int w = this.random.Next(m / 50);
int h = this.random.Next(m / 50);
g.FillEllipse(hatchBrush, x, y, w, h);
}
font.Dispose();
hatchBrush.Dispose();
g.Dispose();
this.image = bitmap;
}
}
}
//////////////////////////////////////////////
///////////////////////captchaCreate.aspx.cs//////////////
protected void Page_Load(object sender, EventArgs e)
{
CaptchaImage.CaptchaImage ci = new CaptchaImage.CaptchaImage(Session["CaptchaImageText"].ToString(), 180, 40, "Century Schoolbook");
this.Response.Clear();
this.Response.ContentType = "image/jpeg";
ci.Image.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
ci.Dispose();
}
//////////////////////////////////////////////
///////////////////////valiadateCaptcha.aspx.cs//////////////
private Random random = new Random();
private string GenerateRandomCode()
{
string s = "";
for (int i = 0; i < 6; i++)
s = String.Concat(s, this.random.Next(12).ToString());
return s;
}
protected void Page_Load(object sender, EventArgs e)
{
if (Page.Request.Form["mode"].ToString() == "validate")
{
if (Page.Request.Form["text"].ToString() == Session["CaptchaImageText"].ToString())
{
Response.Write("y");
}
else
{
Response.Write("n");
}
}
else if (Page.Request.Form["mode"].ToString() == "change")
{
Session["CaptchaImageText"] = GenerateRandomCode();
}
}
//////////////////////////////////////////////
///////////////////////DoCallBack.js//////////////
function processReqChange()
{
if(req.readyState==4){
if(req.status==200){
eval(what)
}else{
alert("There was a problem retrieving the XML data:\n"+req.responseText)
}
}
}
function DoCallback(a,b){
if(window.XMLHttpRequest)
{
req=new XMLHttpRequest;req.onreadystatechange=processReqChange;req.open("POST",url,false);
req.setRequestHeader("Content-Type","application/x-www-form-urlencoded");req.send(a);
var c=req.responseText.substring(0,1);
document.getElementById(b).innerHTML=c}
else if(window.ActiveXObject)
{
req=new ActiveXObject("Microsoft.XMLHTTP");
if(req){
req.onreadystatechange=processReqChange;
req.open("POST",url,false);
req.setRequestHeader("Content-Type","application/x-www-form-urlencoded");req.send(a);
var c=req.responseText.substring(0,1);
document.getElementById(b).innerHTML=c;
}
}
}
//////////////////////////////////////////////
///////////////////////Default.aspx//////////////
<script src="js/DoCallBack.js" type="text/javascript"></script>
<script src="js/jquery-1.6.4.min.js" type="text/javascript"></script>
<div class="top-bar">
<h1>
Example : Create Captcha By asp.net</h1>
</div>
<div style="width: 100%">
<div style="width: 300px; padding-left: 20px;">
Enter Captcha Text
<input id="txtCaptcha" type="text" style="width: 70%" runat="server" />
</div>
<div style="height: 10px">
</div>
<div style="width: 300px; padding-left: 20px; height: 50px">
<div style="float: left; width: 180px; height: 40px">
<img src="captchaCreate.aspx" id="imgcap" />
</div>
<div style="float: left; padding-left: 10px; padding-top: 10px;">
<img src="images/captchaRefress.ico" alt="loading.." style="height: 16px; width: 16px;
cursor: pointer" onclick="reloadCaptcha();" />
</div>
<div style="clear: both">
</div>
</div>
<div style="width: 300px; padding-left: 20px;">
<input id="btnValidate" type="button" value="Validate Captcha" onclick="validateCaptcha();" />
</div>
<div id="spanValidUserName" style="display: none">
</div>
</div>
<script language="javascript" type="text/javascript">
function reloadCaptcha() {
url = "valiadateCaptcha.aspx";
what = "";
DoCallback("mode=change", "spanValidUserName");
document.getElementById('imgcap').src = "captchaCreate.aspx?i=" + Math.floor(Math.random() * 11);
return false;
}
function validateCaptcha() {
var a = document.getElementById("<%=txtCaptcha.ClientID %>").value;
if (a == "") {
alert("Please enter captcha text!");
return false;
}
url = "valiadateCaptcha.aspx";
what = "";
DoCallback("mode=validate&text=" + a, "spanValidUserName");
if (document.getElementById('spanValidUserName').innerHTML == "y") {
alert("correct captcha ");
}
else {
alert("Please enter correct captcha !");
}
return false;
}
</script>
//////////////////////////////////////////////
///////////////////////Default.aspx.cs//////////////
private Random random = new Random();
private string GenerateRandomCode()
{
string s = "";
for (int i = 0; i < 6; i++)
s = String.Concat(s, this.random.Next(12).ToString());
return s;
}
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
Session["CaptchaImageText"] = GenerateRandomCode();
else
{
}
}
///////////////////////////////////////////////
