using System;

using System.Drawing;

using System.Drawing.Drawing2D;

using System.Drawing.Imaging;

using System.Drawing.Text;

 

namespace CaptchaImage

{

      /// <summary>

      /// Summary description for CaptchaImage.

      /// </summary>

      public class CaptchaImage

      {

            // Public properties (all read-only).

            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; }

            }

 

            // Internal properties.

            private string text;

            private int width;

            private int height;

            private string familyName;

            private Bitmap image;

 

            // For generating random numbers.

            private Random random = new Random();

 

            // ====================================================================

            // Initializes a new instance of the CaptchaImage class using the

            // specified text, width and height.

            // ====================================================================

            public CaptchaImage(string s, int width, int height)

            {

                  this.text = s;

                  this.SetDimensions(width, height);

                  this.GenerateImage();

            }

 

            // ====================================================================

            // Initializes a new instance of the CaptchaImage class using the

            // specified text, width, height and font family.

            // ====================================================================

            public CaptchaImage(string s, int width, int height, string familyName)

            {

                  this.text = s;

                  this.SetDimensions(width, height);

                  this.SetFamilyName(familyName);

                  this.GenerateImage();

            }

 

            // ====================================================================

            // This member overrides Object.Finalize.

            // ====================================================================

            ~CaptchaImage()

            {

                  Dispose(false);

            }

 

            // ====================================================================

            // Releases all resources used by this object.

            // ====================================================================

            public void Dispose()

            {

                  GC.SuppressFinalize(this);

                  this.Dispose(true);

            }

 

            // ====================================================================

            // Custom Dispose method to clean up unmanaged resources.

            // ====================================================================

            protected virtual void Dispose(bool disposing)

            {

                  if (disposing)

                        // Dispose of the bitmap.

                        this.image.Dispose();

            }

 

            // ====================================================================

            // Sets the image width and height.

            // ====================================================================

            private void SetDimensions(int width, int height)

            {

                  // Check the width and 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;

            }

 

            // ====================================================================

            // Sets the font used for the image text.

            // ====================================================================

            private void SetFamilyName(string familyName)

            {

                  // If the named font is not installed, default to a system font.

                  try

                  {

                        Font font = new Font(this.familyName, 12F);

                        this.familyName = familyName;

                        font.Dispose();

                  }

                  catch (Exception ex)

                  {

                        this.familyName = System.Drawing.FontFamily.GenericSerif.Name;

                  }

            }

 

            // ====================================================================

            // Creates the bitmap image.

            // ====================================================================

            private void GenerateImage()

            {

                  // Create a new 32-bit bitmap image.

                  Bitmap bitmap = new Bitmap(this.width, this.height, PixelFormat.Format32bppArgb);

 

                  // Create a graphics object for drawing.

                  Graphics g = Graphics.FromImage(bitmap);

                  g.SmoothingMode = SmoothingMode.AntiAlias;

                  Rectangle rect = new Rectangle(0, 0, this.width, this.height);

 

                  // Fill in the background.

                  HatchBrush hatchBrush = new HatchBrush(HatchStyle.SmallConfetti, Color.Aqua, Color.AliceBlue);

                  g.FillRectangle(hatchBrush, rect);

 

                  // Set up the text font.

                  SizeF size;

                  float fontSize = rect.Height + 1;

                  Font font;

                  // Adjust the font size until the text fits within the image.

                  do

                  {

                        fontSize--;

                        font = new Font(this.familyName, fontSize, FontStyle.Bold);

                        size = g.MeasureString(this.text, font);

                  } while (size.Width > rect.Width);

 

                  // Set up the text format.

                  StringFormat format = new StringFormat();

                  format.Alignment = StringAlignment.Center;

                  format.LineAlignment = StringAlignment.Center;

 

                  // Create a path using the text and warp it randomly.

                  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);

 

                  // Draw the text.

                  hatchBrush = new HatchBrush(HatchStyle.LargeConfetti, Color.LightGray, Color.DarkGray);

                  g.FillPath(hatchBrush, path);

 

                  // Add some random noise.

                  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);

                  }

 

                  // Clean up.

                  font.Dispose();

                  hatchBrush.Dispose();

                  g.Dispose();

 

                  // Set the image.

                  this.image = bitmap;

            }

      }

}

 

 

 

using System;

using System.Collections;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Web;

using System.Web.SessionState;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.HtmlControls;

 

namespace CaptchaImage

{

public partial class _Default : System.Web.UI.Page

{

protected System.Web.UI.WebControls.TextBox CodeNumberTextBox;

protected System.Web.UI.WebControls.Button SubmitButton;

protected System.Web.UI.WebControls.Label MessageLabel;

 

// For generating random numbers.

private Random random = new Random();

 

private void Page_Load(object sender, System.EventArgs e)

{

if (!this.IsPostBack)

 

// Create a random code and store it in the Session object.

this.Session["CaptchaImageText"] = GenerateRandomCode();

 

else

{

// On a postback, check the user input.

if (this.CodeNumberTextBox.Text == this.Session["CaptchaImageText"].ToString())

{

// Display an informational message.

this.MessageLabel.CssClass = "info";

this.MessageLabel.Text = "Correct!";

}

else

{

// Display an error message.

this.MessageLabel.CssClass = "error";

this.MessageLabel.Text = "ERROR: Incorrect, try again.";

 

// Clear the input and create a new random code.

this.CodeNumberTextBox.Text = "";

this.Session["CaptchaImageText"] = GenerateRandomCode();

}

}

}

 

//

// Returns a string of six random digits.

//

private string GenerateRandomCode()

{

string s = "";

for (int i = 0; i < 6; i++)

s = String.Concat(s, this.random.Next(10).ToString());

return s;

}

 

#region Web Form Designer generated code

override protected void OnInit(EventArgs e)

{

//

// CODEGEN: This call is required by the ASP.NET Web Form Designer.

//

InitializeComponent();

base.OnInit(e);

}

 

/// <summary>

/// Required method for Designer support - do not modify

/// the contents of this method with the code editor.

/// </summary>

private void InitializeComponent()

{

this.Load += new System.EventHandler(this.Page_Load);

 

}

#endregion

}

}

 

using System;

using System.Collections;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Drawing.Imaging;

using System.Web;

using System.Web.SessionState;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.HtmlControls;

 

namespace CaptchaImage

{

public partial class JpegImage : System.Web.UI.Page

{

private void Page_Load(object sender, System.EventArgs e)

{

// Create a CAPTCHA image using the text stored in the Session object.

CaptchaImage ci = new CaptchaImage(this.Session["CaptchaImageText"].ToString(), 200, 50, "Century Schoolbook");

 

// Change the response headers to output a JPEG image.

this.Response.Clear();

this.Response.ContentType = "image/jpeg";

 

// Write the image to the response stream in JPEG format.

ci.Image.Save(this.Response.OutputStream, ImageFormat.Jpeg);

 

// Dispose of the CAPTCHA image object.

ci.Dispose();

}

 

#region Web Form Designer generated code

override protected void OnInit(EventArgs e)

{

//

// CODEGEN: This call is required by the ASP.NET Web Form Designer.

//

InitializeComponent();

base.OnInit(e);

}

 

/// <summary>

/// Required method for Designer support - do not modify

/// the contents of this method with the code editor.

/// </summary>

private void InitializeComponent()

{

this.Load += new System.EventHandler(this.Page_Load);

}

#endregion

}

}