Archive

novembre 2024

lun

mar

mer

gio

ven

sab

dom

News -

By ale73 at 2012-02-15

To provide a captcha system I have created the following step

Create a rectangle

Create random number from 1 to 10000
Add random lines across the rectangle

Add random point across the rectangle

using System.Drawing and System.Drawing.Image here is the code in Page looa of Default.aspx.cs

protected void Page_Load(object sender, EventArgs e)
{

Response.ContentType = "image/png";

Random r= new Random();
int numr = r.Next(100000);
Bitmap img = new Bitmap(400, 100);
Graphics g = Graphics.FromImage(img);
g.FillRectangle(Brushes.Blue, 0, 0, 400, 200);
Font f = new Font("Arial", 30);
g.DrawString(Convert.ToString(numr), f, Brushes.White, 120, 20);
Pen p = new Pen(Color.Yellow, 2);
Random rp = new Random();
Random r2 = new Random();

int n = r2.Next(0, 5);
for (int i = 0; i <= n; i++)
{
int nrp = rp.Next(0, 100);

g.DrawLine(p, 0, nrp, 400, nrp);
}
int numpunti = r2.Next(0, 500);
System.Drawing.Image imgp = System.Drawing.Image.FromFile(Server.MapPath("puntorosso2.png"));
for (int j = 0; j < numpunti; j++)
{
int x1 = rp.Next(0, 400);
int y1 = rp.Next(0, 100);
g.DrawImage(imgp, x1, y1);
}
img.Save(Response.OutputStream, ImageFormat.Png);
g.Dispose();
img.Dispose();
imgp.Dispose();
Response.End();
}

if you want iclude in your page, you can do this by

here is the code to download

captcha.rar

Information of Blog

Home

Welcome all!!

Last Posts

Categories
classic ASP (2)
DotNET (3)