In this article I am explain How to add text on image. We often create applications where we
retrieve images from the database and display it on the page. At times, we may
need to add some text or a copyright notice dynamically on the images.
Default.aspx
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Write Text On Image</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<img alt="Image" id="imgdynamitext"
src="TextOnImageHandler.ashx?id=5"
/>
</div>
</form>
</body>
</html>
I am using an HttpHandler to get images and then add some text to
the retrieved images.
TextOnImageHandler.cs
<%@ WebHandler
Language="C#"
Class="TextOnImageHandler"
%>
using System;
using System.Web;
using System.Drawing;
using System.Configuration;
using System.ComponentModel;
using System.Drawing.Imaging;
using System.Data;
using System.Data.SqlClient;
public class TextOnImageHandler : IHttpHandler
{
byte[] empPic = null;
long seq = 0;
public void
ProcessRequest(HttpContext context)
{
Int32 empno;
if (context.Request.QueryString["id"] != null)
empno = Convert.ToInt32(context.Request.QueryString["id"]);
else
throw new ArgumentException("No
parameter specified");
// Convert Byte[] to Bitmap
Bitmap newBmp =
ConvertToBitmap(ShowEmpImage(empno));
// Watermark Text to be added to image
string text = "Asp.Net
Jitendra";
Bitmap convBmp = AddTextToImage(newBmp, text);
convBmp.Save(context.Response.OutputStream, ImageFormat.Jpeg);
newBmp.Dispose();
convBmp.Dispose();
}
// Add Watermark Text to Image
protected Bitmap
AddTextToImage(Bitmap bImg, string msg)
{
// To void the error due to Indexed Pixel Format
Image img = new Bitmap(bImg, new Size(bImg.Width, bImg.Height));
Bitmap tmp = new Bitmap(img);
Graphics graphic = Graphics.FromImage(tmp);
// Watermark effect
SolidBrush brush = new
SolidBrush(Color.FromArgb(120,
255, 255, 255));
// Draw the text string to the Graphics object at a given
position.
graphic.DrawString(msg, new Font("Times New
Roman", 16, FontStyle.Italic),
brush, new PointF(10,
30));
graphic.Dispose();
return tmp;
}
// Convert byte array to Bitmap (byte[] to Bitmap)
protected Bitmap
ConvertToBitmap(byte[] bmp)
{
TypeConverter tc = TypeDescriptor.GetConverter(typeof(Bitmap));
Bitmap b = (Bitmap)tc.ConvertFrom(bmp);
return b;
}
public byte[]
ShowEmpImage(int empno)
{
string conn = ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
SqlConnection connection = new SqlConnection(conn);
string sql = "SELECT
photo FROM Employees WHERE EmployeeID = @ID";
SqlCommand cmd = new
SqlCommand(sql, connection);
cmd.CommandType = CommandType.Text;
cmd.Parameters.AddWithValue("@ID",
empno);
connection.Open();
SqlDataReader dr = cmd.ExecuteReader();
if (dr.Read())
{
seq = dr.GetBytes(0, 0, null, 0, int.MaxValue) - 1;
empPic = new byte[seq
+ 1];
dr.GetBytes(0, 0, empPic, 0, Convert.ToInt32(seq));
connection.Close();
}
return empPic;
}
public bool
IsReusable
{
get
{
return false;
}
}
}
Output:-
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