Resizing a Signature in PDF

Environment

Product	RadSignature for ASP.NET AJAX
Version	all

Description

I want to resize a signature in a PDF document using RadSignature for ASP.NET AJAX. I have code that places the signature in the PDF, but I'm not able to resize it to a smaller size to fit it in the form.

Solution

The solution is based on the Signing Pdf Documents demo. To resize the signature in the PDF document, you can modify the code as follows:

Before translating the position of the foregroundContentOwner, apply a scaling transformation to resize it. Choose the scaling factors (width and height) based on your requirements.

using (pageWriter.SaveContentPosition())
{
    // Scale the signature
    double scaleX = 0.3; // Example scaling factor for width
    double scaleY = 0.3; // Example scaling factor for height
    pageWriter.ContentPosition.Scale(scaleX, scaleY);

    // Adjust the translation values
    double xCenteringTranslation = ((pageSource.Size.Width - (foregroundContentOwner.Size.Width * scaleX)) - 120) / 2;
    double yCenteringTranslation = ((pageSource.Size.Height - (foregroundContentOwner.Size.Height * scaleY)) - 110);

    pageWriter.ContentPosition.Translate(xCenteringTranslation, yCenteringTranslation);
    pageWriter.WriteContent(foregroundContentOwner);
}

This modified code will scale the signature and adjust its position to fit it within the PDF document. The example scaling factors used are 0.3 for both width and height. Adjust these values according to your requirements.

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Web.UI;
using System.Windows;
using Telerik.Web.UI;
using Telerik.Windows.Documents.Fixed;
using Telerik.Windows.Documents.Fixed.FormatProviders.Pdf;
using Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Streaming;
using Telerik.Windows.Documents.Fixed.Model;
using Telerik.Windows.Documents.Fixed.Model.Data;
using Telerik.Windows.Documents.Fixed.Model.Editing;

namespace Telerik.Web.Examples.Signature.SigningPdfDocuments
{
    public partial class DefaultCS : System.Web.UI.Page
    {
        protected void RadAjaxManager1_AjaxRequest(object sender, Telerik.Web.UI.AjaxRequestEventArgs e)
        {
            var fileName = e.Argument.Split(';')[0];
            var base64 = e.Argument.Split(',')[1];

            RadPdfViewer1.PdfjsProcessingSettings.FileSettings.Data = PreparePdf(base64);
        }


        public string PreparePdf(string pdfData)
        {
            byte[] resultingBytes = null;
            byte[] finalBytes = null;

            PdfFormatProvider provider = new PdfFormatProvider();
            byte[] renderedBytes = Convert.FromBase64String(pdfData);

            RadFixedDocument document1 = null;
            RadFixedDocument document2 = provider.Import(renderedBytes);

            string filePath = Server.MapPath("Documents/Document.pdf");

            using (FileStream input = new FileStream(filePath, FileMode.Open, FileAccess.Read))
            {
                document1 = provider.Import(input);
            }

            using (MemoryStream ms = new MemoryStream())
            {
                provider.Export(document1, ms);
                resultingBytes = ms.ToArray();
            }

            finalBytes = AppendContent(resultingBytes, document2);
            string result = Convert.ToBase64String(finalBytes);

            return result;
        }
        private byte[] AppendContent(byte[] resultingBytes, RadFixedDocument document2)
        {
            RadFixedPage foregroundContentOwner = document2.Pages[0];

            MemoryStream ms = new MemoryStream();
            byte[] renderedBytes = null;
            using (MemoryStream stream = new MemoryStream(resultingBytes))
            {
                using (PdfFileSource fileSource = new PdfFileSource(stream))
                {
                    using (PdfStreamWriter fileWriter = new PdfStreamWriter(ms, true))
                    {
                        foreach (PdfPageSource pageSource in fileSource.Pages)
                        {
                            using (PdfPageStreamWriter pageWriter = fileWriter.BeginPage(pageSource.Size, pageSource.Rotation))
                            {
                                pageWriter.WriteContent(pageSource);

                                using (pageWriter.SaveContentPosition())
                                {
                                    // Scale the signature
                                    double scaleX = 0.3; // Example scaling factor for width
                                    double scaleY = 0.3; // Example scaling factor for height
                                    pageWriter.ContentPosition.Scale(scaleX, scaleY);

                                    // Adjust the translation values
                                    double xCenteringTranslation = ((pageSource.Size.Width - (foregroundContentOwner.Size.Width * scaleX)) - 120) / 2;
                                    double yCenteringTranslation = ((pageSource.Size.Height - (foregroundContentOwner.Size.Height * scaleY)) - 110);

                                    pageWriter.ContentPosition.Translate(xCenteringTranslation, yCenteringTranslation);
                                    pageWriter.WriteContent(foregroundContentOwner);
                                }
                            }
                        }
                    }
                }
            }
            renderedBytes = ms.ToArray();
            return renderedBytes;
        }

        protected void Page_PreRender(object sender, EventArgs e)
        {
            RadSkinManager.GetCurrent(Page).Skin = "Silk";
        }
    }
}

Notes

• Ensure that you have the latest version of RadSignature for ASP.NET AJAX.
• Adjust the scaling factors (scaleX and scaleY) according to your requirements to resize the signature.
• Modify the translation values (xCenteringTranslation and yCenteringTranslation) to adjust the position of the signature after scaling.
• This solution is based on the Signing PDF Documents demo and may require additional modifications to fit your implementation.

See Also

• RadSignature for ASP.NET AJAX Documentation
• Signing PDF Documents Demo