Add watermark text to Image in ASP.Net using C# and VB.Net

Hi counterkin,

Refer below sample.

HTML

<asp:FileUpload ID="FileUpload1" runat="server" />
<asp:Button Text="Upload" runat="server" OnClick="Upload" />

Namespaces

C#

using System.IO;
using System.Drawing;
using System.Drawing.Imaging;

VB.Net

Imports System.IO
Imports System.Drawing
Imports System.Drawing.Imaging

Code

C#

protected void Upload(object sender, EventArgs e)
{
    string watermarkText = "© ASPSnippets.com";

    //Get the file name.
    string fileName = Path.GetFileNameWithoutExtension(FileUpload1.PostedFile.FileName) + ".png";

    FileUpload1.SaveAs(@"C:\project\watermark\uploads\" + fileName);

    //Read the File into a Bitmap.
    using (Bitmap bmp = new Bitmap(FileUpload1.PostedFile.InputStream, false))
    {
        using (Graphics grp = Graphics.FromImage(bmp))
        {
            //Set the Color of the Watermark text.
            Brush brush = new SolidBrush(Color.Red);

            //Set the Font and its size.
            Font font = new System.Drawing.Font("Arial", 30, FontStyle.Bold, GraphicsUnit.Pixel);

            //Determine the size of the Watermark text.
            SizeF textSize = new SizeF();
            textSize = grp.MeasureString(watermarkText, font);

            //Position the text and draw it on the image.
            Point position = new Point((bmp.Width - ((int)textSize.Width + 10)), (bmp.Height - ((int)textSize.Height + 10)));
            grp.DrawString(watermarkText, font, brush, position);

            using (MemoryStream memoryStream = new MemoryStream())
            {
                //Save the Watermarked image to the MemoryStream.
                bmp.Save(memoryStream, ImageFormat.Png);
                memoryStream.Position = 0;

                FileStream stream = new FileStream(@"C:\project\watermark\uploads\" + fileName, FileMode.Create, FileAccess.Write);
                memoryStream.WriteTo(stream);
            }
        }
    }
}

VB.Net

Protected Sub Upload(sender As Object, e As EventArgs)
    Dim watermarkText As String = "© ASPSnippets.com"

    'Get the file name.
    Dim fileName As String = Path.GetFileNameWithoutExtension(FileUpload1.PostedFile.FileName) & ".png"
    FileUpload1.SaveAs("C:\project\watermark\uploads\" & fileName)

    'Read the File into a Bitmap.
    Using bmp As New Bitmap(FileUpload1.PostedFile.InputStream, False)
        Using grp As Graphics = Graphics.FromImage(bmp)
            'Set the Color of the Watermark text.
            Dim brush As Brush = New SolidBrush(Color.Red)

            'Set the Font and its size.
            Dim font As Font = New System.Drawing.Font("Arial", 30, FontStyle.Bold, GraphicsUnit.Pixel)

            'Determine the size of the Watermark text.
            Dim textSize As New SizeF()
            textSize = grp.MeasureString(watermarkText, font)

            'Position the text and draw it on the image.
            Dim position As New Point((bmp.Width - (CInt(textSize.Width) + 10)), (bmp.Height - (CInt(textSize.Height) + 10)))
            grp.DrawString(watermarkText, font, brush, position)

            Using memoryStream As New MemoryStream()
                'Save the Watermarked image to the MemoryStream.
                bmp.Save(memoryStream, ImageFormat.Png)
                memoryStream.Position = 0

                Dim stream As FileStream = New FileStream("C:\project\watermark\uploads\" & fileName, FileMode.Create, FileAccess.Write)
                memoryStream.WriteTo(stream)
            End Using
        End Using
    End Using
End Sub