Hello,

I'm trying to rewrite a PDF-generator function that creates a PDF from HTML (which is the result of an XSLT+xml transform) using another HTML to PDF library to a new function that uses the Telerik methods. That works Ok, but there are 2 things I can't figure out how to do (if even possible) :

- The HTML content consists of a table with uneven row heights, depending on the content. Some rows contain images, some don't. So, I can't determine beforehand which row needs to start on a new page. Currently, I use page-break-inside: avoid on the rows, and that works with the other library, but not with the Telerik methods. Some rows are split over two pages. How can I prevent an element from breaking up over two pages?

- With the current library, I'm able to provide a separate PDF file that is used as a background for every rendered page. That PDF is a single-page PDF with the 'corporate stationery' (don't know how that's called ;-), so the resulting PDF contains multiple pages with the HTML output in the company style. Is something like that possible with the Telerik methods?  I know how to draw a small HTML snippet on a single PDF page, but I can't figure out how to convert HTML to PDF with this background on every page.

Any help is appreciated.

Regards,
Kees

Is it possible to add text to headers based on variables/database fields? I'm trying to loop through a table and use a field within the table as a page title, but all information I could find on this points to it being impossible in Telerik. Guidance would be much appreciated. 

Thanks

I am doing some document processing and want to use Telerik to display and edit. I need access to the paraId and textId elements of the docx "document" XML. I have explored the object model in the debugger and do not see these attributes. Are they available in the imported model?

Thanks.

 

The contents of an uploaded .docx file is being cut-off when converted to .pdf file.

 

Code snippet:

Can someone confirm if this a Telerik side issue, or am I missing a setting or config?

 

Thanks!

Can someone help me figure out what is wrong here?  I'm getting ad horribly vague Null exception.

 

var docxProvider = new Telerik.Windows.Documents.Flow.FormatProviders.Docx.DocxFormatProvider();
var pdfProvider = new Telerik.Windows.Documents.Flow.FormatProviders.Pdf.PdfFormatProvider();
RadFlowDocument document = new RadFlowDocument();
byte[] docBytes = File.ReadAllBytes(path);

document = docxProvider.Import(docBytes);    ERROR HERE

var resultBytes = pdfProvider.Export(document);

File.WriteAllBytes(resultPath, resultBytes);

 

The document i'm trying to load contains tables and images within the tables (jpeg barcodes)

I have verified that pretty much every other tool i use can read the file without issue. 

The goal is ultimately to export the file as a PDF.

 

Error details:

{"Object reference not set to an instance of an object."}

   at Telerik.Windows.Documents.Flow.FormatProviders.Docx.Model.Elements.Document.ParagraphPropertiesElement.OnAfterRead(IDocxImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase`3.OnAfterRead(IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.Read(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.ReadChildElements(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.Read(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.ReadChildElements(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.Read(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.ReadChildElements(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.Read(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.ReadChildElements(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.Read(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.ReadChildElements(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Elements.OpenXmlElementBase.Read(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Parts.OpenXmlPartBase.Import(IOpenXmlReader reader, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.Model.Parts.OpenXmlPartBase.Import(Stream stream, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.OpenXmlImporter`1.ImportPartFromArchive(ZipArchiveEntry zipEntry, PartBase part, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.FormatProviders.OpenXml.OpenXmlImporter`1.Import(Stream input, IOpenXmlImportContext context)
   at Telerik.Windows.Documents.Flow.FormatProviders.Docx.DocxFormatProvider.ImportOverride(Stream input)
   at Telerik.Windows.Documents.Common.FormatProviders.FormatProviderBase`1.Import(Stream input)
   at Telerik.Windows.Documents.Common.FormatProviders.BinaryFormatProviderBase`1.Import(Byte[] input)
   at IVC_BIPS_Desktop.rfrmMain.ConverDocxToPdf(String path, String resultPath) in C:\Source\IVC Batch Instructions Printing\IVC_BIPS_Desktop\rfrmMain.cs:line 499

Hi,

i have added and image and some text inside the digital signature and and set them inside properly but when i set the position of the signature field before the signature field like i was showing in below screenshot 


above screenshot i have added the signature field placed the top of the Letter M but when i validate the signature manually but in output the signature field position is not correct as i set the above screenshot below is the screenshot that you can check the position of the signature field

i don't know whats strange can anyone help me this to get it out  

i am getting the Telerik.Windows.Documents.Fixed.Exceptions.NotSupportedImageFormatException: 'Not supported image format.'  this exception in below code can anyone have a solution for that 


// Load the existing PDF from the byte array using PdfFormatProvider
using (MemoryStream inputStream = new MemoryStream(inDocByte))
{
    // Create PdfFormatProvider and load the existing document
    PdfFormatProvider provider = new PdfFormatProvider();
    RadFixedDocument document = provider.Import(inputStream);

    int pageNo = (signInfo.DigitalSignPage() == 0 ? 1 : document.Pages.Count);

    // Path to the image (ensure this is correct)
    System.Drawing.Image signatureImage = null;
    if (signInfo.DigitalSignMode() == 2 && HttpContext.Current.Session["imagesyncfusion"] != null)
    {
        signatureImage = (System.Drawing.Image)HttpContext.Current.Session["imagesyncfusion"];
    }
    // Check if digital signature is needed
    if (signInfo.UseDigitalSign())
    {
        if ((signInfo.DigitalSignMode() == 1) || (signInfo.DigitalSignMode() == 2))
        {
            double signaturePositionLeft = (double)signInfo.DigitalSignLeftInPoints();
            double signaturePositionTop = (double)signInfo.DigitalSignTopInPoints();
            double signatureFieldWidth = (double)signInfo.DigitalSignWidthInPoints();
            double signatureFieldHeight = (double)signInfo.DigitalSignHeightInPoints();
            RadFixedPage radFixedPage = document.Pages[pageNo - 1];

            if (!string.IsNullOrEmpty(customSignatureDetails))
            {
                // Movable signature case: Adjust the signature field based on custom details
                signatureFieldWidth = signaturePositionLeft + (double)signInfo.DigitalSignWidthInPoints();
                signatureFieldHeight = signaturePositionTop + (double)signInfo.DigitalSignHeightInPoints();

                string[] separator = new string[] { "!_!" };
                string[] offsetArray = customSignatureDetails.Split(separator, StringSplitOptions.RemoveEmptyEntries);

                if (offsetArray.Length >= 9)
                {
                    float offsetLeft = returnFloatWithCultureValue(offsetArray[0]);
                    float offsetTop = returnFloatWithCultureValue(offsetArray[1]);
                    float docHeight = returnFloatWithCultureValue(offsetArray[2]);
                    float greenDivHeight = returnFloatWithCultureValue(offsetArray[3]);
                    float greenDivWidth = returnFloatWithCultureValue(offsetArray[4]);
                    float dpi_x = returnFloatWithCultureValue(offsetArray[6]);
                    float dpi_y = returnFloatWithCultureValue(offsetArray[7]);
                    pageNo = int.Parse(offsetArray[8]);

                    // Calculate positions for drawing the text div;
                    signaturePositionLeft = (offsetLeft / dpi_x) * 72;
                    signaturePositionTop = (offsetTop / dpi_y) * 72;
                    signatureFieldWidth = (greenDivWidth / dpi_y) * 72;
                    signatureFieldHeight = (greenDivHeight / dpi_x) * 72;
                }
            }
            else
            {
                // Non-movable case: Place the signature field in a fixed location
                radFixedPage = document.Pages[pageNo - 1];
                Tuple<double, double> k = null;

                if (signatureImage != null)
                {
                    k = calculateAspectRatioFit(signatureImage.Width, signatureImage.Height, signatureFieldWidth, signatureFieldHeight);
                    signatureFieldWidth = k.Item1;
                    signatureFieldHeight = k.Item2;
                }

                signaturePositionLeft = radFixedPage.Size.Height - (double)(signatureFieldWidth + signatureFieldHeight + 1);
                signaturePositionTop = signaturePositionTop + 1; // +1 For border size
                                                                 //pdfForm.FormSource.Size = new Telerik.Documents.Primitives.Size(signatureFieldWidth, signatureFieldHeight);
            }

            // Create a new form to place the signature field
            Form pdfForm = new Form();
            pdfForm.FormSource = new FormSource();
            FixedContentEditor editor = new FixedContentEditor(pdfForm.FormSource);
            pdfForm.FormSource.Size = new Telerik.Documents.Primitives.Size(signatureFieldWidth, signatureFieldHeight);

            // Drawing the image at the starting position (left side of the signature field)
            imageWidth = signatureFieldWidth / 2;  // Half the width for the image
            double imageHeight = signatureFieldHeight;  // Use full height of the signature field

            if (signatureImage != null)
            {
                using (MemoryStream ms = new MemoryStream())
                {
                    signatureImage.Save(ms, signatureImage.RawFormat);
                    ms.Position = 0;
                    editor.DrawImage(ms, new Telerik.Documents.Primitives.Size(imageWidth, imageHeight));
                }
            }

            // Prepare text to draw beside the signature image
            string textToDraw = $"Digitally signed by {certificate.FriendlyName} \nDate: {DateTime.Now:yyyy.MM.dd HH:mm:ss zzz} \nReason: {pdfSignature.Signature.Properties.Reason} \nLocation: {pdfSignature.Signature.Properties.Location}";

            // Set text width and calculate font size
            double textWidth = signatureFieldWidth - imageWidth;
            double fontSize = CalculateFontSize(signatureFieldWidth - 23, signatureFieldHeight, textToDraw);

            // Define the position for the text and draw it
            Telerik.Windows.Documents.Fixed.Model.Editing.Block textBlock = new Telerik.Windows.Documents.Fixed.Model.Editing.Block();
            double textPositionLeft = signaturePositionLeft;  // Adding a 5px gap after the image
            textBlock.TextProperties.FontSize = fontSize;
            textBlock.InsertText($"Digitally signed by {certificate.FriendlyName}");
            textBlock.InsertText($" Date: {DateTime.Now:yyyy.MM.dd HH:mm:ss zzz}");
            textBlock.InsertText($" Reason: {pdfSignature.Signature.Properties.Reason}");
            textBlock.InsertText($" Location: {pdfSignature.Signature.Properties.Location}");
            
            Rect boundingRect;
            if (signatureImage != null)
            {
                boundingRect = new Rect(imageWidth, 5, textWidth, signatureFieldHeight);
            }
            else
            {
                boundingRect = new Rect(textPositionLeft, 5, textWidth, signatureFieldHeight);
            }
            textBlock.Draw(editor, boundingRect);
            //editor.DrawBlock(textBlock);
            // Create the SignatureWidget and position it on the PDF page
            SignatureWidget signatureWidget = pdfSignature.Widgets.AddWidget();
            signatureWidget.Content.NormalContentSource = pdfForm.FormSource;
            signatureWidget.Rect = new Rect(signaturePositionLeft, 0, signatureFieldWidth, signatureFieldHeight);
            signatureWidget.RecalculateContent();

            // Add signature widget to the page and draw the content
            RadFixedPage pdfPage = document.Pages[pageNo - 1];
            FixedContentEditor pageEditor = new FixedContentEditor(pdfPage);
            pageEditor.Position.Translate(signaturePositionLeft , signaturePositionTop + 258.3824795800782);
            pageEditor.DrawForm(pdfForm.FormSource);

            // Add the signature field to the document's AcroForm
            document.AcroForm.FormFields.Add(pdfSignature);

        }

    }
    // Export the document to a byte array and return
    using (MemoryStream memoryStream = new MemoryStream())
    {

        Telerik.Documents.ImageUtils.ImagePropertiesResolver defaultImagePropertiesResolver = new Telerik.Documents.ImageUtils.ImagePropertiesResolver();
        Telerik.Windows.Documents.Extensibility.FixedExtensibilityManager.ImagePropertiesResolver = defaultImagePropertiesResolver;
        PdfExportSettings settings = new PdfExportSettings() { ImageQuality = ImageQuality.High };
        //PdfFormatProvider provider = new PdfFormatProvider();
        provider.ExportSettings = settings;
        provider.Export(document, memoryStream);
        outDocPdf = memoryStream.ToArray();
    }

public static void SignPDFSynfusion(SignatureInfo signInfo, byte[] inDocByte, Cert objCert, string customSignatureDetails, out byte[] outDocPdf)
{
    // Dimensions and positions for the signature field
    double signatureFieldWidth; // Width of the signature field
    double signatureFieldHeight;
    double signaturePositionLeft;
    double signaturePositionTop;
   
    // Getting TimeStamp Details from Database..
    TimeStampSettings objTimeStampSettings = new TimeStampSettings();
    TimeStampInfo objTimeStampInfo = (TimeStampInfo)objTimeStampSettings.GetTimeStamp();
    PfxSettings objPfxSettings = new PfxSettings();

    // Params to take account in the input
    bool displaySignature = Convert.ToBoolean(HttpContext.Current.Session["showSign"]);

    bool needTimeStamp = false;
    string TsaServerUrl = "";
    string TsaServerUser = "";
    string TsaServerPassword = "";
    string strPasswrd = string.Empty;
    double imageWidth = 0;

    if (objTimeStampInfo != null)
    {
        needTimeStamp = (bool)objTimeStampInfo.TimeStampNeeded;
        TsaServerUrl = objTimeStampInfo.TimeStampUrl;

        if ((bool)objTimeStampInfo.AuthNeeded)
        {
            TsaServerUser = objTimeStampInfo.UserName;
            strPasswrd = SecurQueryString.decryptQueryString(objTimeStampInfo.Password);
            TsaServerPassword = strPasswrd;
        }
    }
    // Load the certificate
    X509Certificate2 certificate = new X509Certificate2(objCert.CertArray, objCert.Password);

    // Create a SignatureField and assign the digital signature to it
    SignatureField pdfSignature = new SignatureField("SignatureField");
    pdfSignature.Signature = new Telerik.Windows.Documents.Fixed.Model.DigitalSignatures.Signature(certificate);

    // Set signature details
    string strNotAvailable = HttpContext.GetGlobalResourceObject("GlobalResources", "lblNotAvlbl").ToString();
    pdfSignature.Signature.Properties.Reason = strNotAvailable;
    pdfSignature.Signature.Properties.ContactInfo = strNotAvailable;
    pdfSignature.Signature.Properties.Location = strNotAvailable;

    // Create a new form to place the signature field
    Form pdfForm = new Form();
    pdfForm.FormSource = new FormSource();

    // Load the existing PDF from the byte array using PdfFormatProvider
    using (MemoryStream inputStream = new MemoryStream(inDocByte))
    {
        // Create PdfFormatProvider and load the existing document
        PdfFormatProvider provider = new PdfFormatProvider();
        RadFixedDocument document = provider.Import(inputStream);

        int pageNo = (signInfo.DigitalSignPage() == 0 ? 1 : document.Pages.Count);
        try
        {
            if (needTimeStamp)
            {
                //.TimeStampServer = new TimeStampServer(new Uri(TsaServerUrl), TsaServerUser, TsaServerPassword);
            }
        }
        catch (Exception ex)
        { }

        // Path to the image (ensure this is correct)
        System.Drawing.Image signatureImage = null;
        if (signInfo.DigitalSignMode() == 2 && HttpContext.Current.Session["imagesyncfusion"] != null)
        {
            signatureImage = (System.Drawing.Image)HttpContext.Current.Session["imagesyncfusion"];
        }
        //var signatureImage = (System.Drawing.Image)HttpContext.Current.Session["imagesyncfusion"];

        if (signInfo.UseDigitalSign())
        {
            if ((signInfo.DigitalSignMode() == 1) || (signInfo.DigitalSignMode() == 2))
            {
                signaturePositionLeft = (double)signInfo.DigitalSignLeftInPoints();
                signaturePositionTop = (double)signInfo.DigitalSignTopInPoints();
                signatureFieldWidth = (double)signInfo.DigitalSignWidthInPoints();
                signatureFieldHeight = (double)signInfo.DigitalSignHeightInPoints();
                RadFixedPage radFixedPage = document.Pages[pageNo - 1];
                if (!string.IsNullOrEmpty(customSignatureDetails))
                {
                    //Movable case:
                    signatureFieldWidth = signaturePositionLeft + (double)signInfo.DigitalSignWidthInPoints();
                    signatureFieldHeight = signaturePositionTop + (double)signInfo.DigitalSignHeightInPoints();

                    string[] separator = new string[] { "!_!" };
                    string[] offsetArray = customSignatureDetails.Split(separator, StringSplitOptions.RemoveEmptyEntries);

                    if (offsetArray.Length >= 9)
                    {
                        float offsetLeft = returnFloatWithCultureValue(offsetArray[0]);
                        float offsetTop = returnFloatWithCultureValue(offsetArray[1]);
                        float docHeight = returnFloatWithCultureValue(offsetArray[2]);
                        float greenDivHeight = returnFloatWithCultureValue(offsetArray[3]);
                        float greenDivWidth = returnFloatWithCultureValue(offsetArray[4]);
                        float dpi_x = returnFloatWithCultureValue(offsetArray[6]);
                        float dpi_y = returnFloatWithCultureValue(offsetArray[7]);
                        pageNo = int.Parse(offsetArray[8]);

                        // Calculate positions for drawing the text div;
                        signaturePositionLeft = (offsetLeft / dpi_x) * 72;
                        signaturePositionTop = (offsetTop / dpi_y) * 72;
                        signatureFieldWidth = (greenDivWidth / dpi_y) * 72;
                        signatureFieldHeight = (greenDivHeight / dpi_x) * 72;

                        pdfForm.FormSource.Size = new Telerik.Documents.Primitives.Size(signatureFieldWidth, signatureFieldHeight);

                    }
                }
                else
                {
                    //Non-movable case:
                    radFixedPage = document.Pages[pageNo - 1];
                    Tuple<double, double> k = null;

                    if (signatureImage != null)
                    {
                        k = calculateAspectRatioFit(signatureImage.Width, signatureImage.Height, signatureFieldWidth, signatureFieldHeight);
                        signatureFieldWidth = k.Item1;
                        signatureFieldHeight = k.Item2;
                    }

                    signaturePositionLeft = radFixedPage.Size.Height - (double)(signatureFieldWidth + signatureFieldHeight + 1);
                    signaturePositionTop = signaturePositionTop + 1; // +1 For border size
                    pdfForm.FormSource.Size = new Telerik.Documents.Primitives.Size(signatureFieldWidth, signatureFieldHeight);
                }
                FixedContentEditor editor = new FixedContentEditor(pdfForm.FormSource);
                // Drawing the image at the starting position (left side of the signature field)
                imageWidth = signatureFieldWidth / 2;  // Half the width for the image
                double imageHeight = signatureFieldHeight;  // Use full height of the signature field

                if (signatureImage == null)
                {

                }
                else
                {
                    // Create a memory stream to hold the image
                    using (MemoryStream ms = new MemoryStream())
                    {
                        // Save the image to the memory stream
                        signatureImage.Save(ms, signatureImage.RawFormat);

                        // Reset the stream position to the beginning
                        ms.Position = 0;

                        // Pass the memory stream to the DrawImage method
                        editor.DrawImage(ms, new Telerik.Documents.Primitives.Size(imageWidth, imageHeight));
                    }
                }
                string textToDraw = $"Digitally signed by {certificate.FriendlyName} \nDate: {DateTime.Now.ToString("yyyy.MM.dd HH:mm:ss zzz")} \nReason: {pdfSignature.Signature.Properties.Reason} \nLocation: {pdfSignature.Signature.Properties.Location}";
                // Set the width of the text area (remaining space after the image)
                double textWidth = signatureFieldWidth - imageWidth;
                double dsd = CalculateFontSize(textWidth, signatureFieldHeight, textToDraw);

                // Now, draw the text next to the image (on the right side), within the remaining space
                Telerik.Windows.Documents.Fixed.Model.Editing.Block textBlock = new Telerik.Windows.Documents.Fixed.Model.Editing.Block();
                double textPositionLeft = signaturePositionLeft + imageWidth;  // Adding a 5px gap after the image
                textBlock.TextProperties.FontSize = 8;
                textBlock.InsertText($"Digitally signed by {certificate.FriendlyName}");
                textBlock.InsertText($" Date: {DateTime.Now.ToString("yyyy.MM.dd HH:mm:ss zzz")}");
                textBlock.InsertText($" Reason: {pdfSignature.Signature.Properties.Reason}");
                textBlock.InsertText($" Location: {pdfSignature.Signature.Properties.Location}");
                Rect boundingRect = new Rect(textPositionLeft - 8, signaturePositionTop - 12, textWidth, signatureFieldHeight);
                textBlock.Draw(editor, boundingRect);

                // Create the SignatureWidget and position it on the PDF page
                SignatureWidget signatureWidget = pdfSignature.Widgets.AddWidget();
                signatureWidget.Content.NormalContentSource = pdfForm.FormSource;
                signatureWidget.Rect = new Rect(signaturePositionLeft, signaturePositionTop, signatureFieldWidth, signatureFieldHeight);
                signatureWidget.RecalculateContent();

                // Add content from the form to the page at the specified position
                RadFixedPage pdfPage = document.Pages[0];  // Assuming you're adding it to the first page
                FixedContentEditor pageEditor = new FixedContentEditor(pdfPage);
                pageEditor.Position.Translate(signaturePositionLeft, signaturePositionTop);
                pageEditor.DrawForm(pdfForm.FormSource);

                // Add the signature field to the document's AcroForm
                document.AcroForm.FormFields.Add(pdfSignature);
            }
        }

        // Use MemoryStream to capture the PDF output and return as a byte array
        using (MemoryStream memoryStream = new MemoryStream())
        {
            // Export the document to the memory stream as a PDF
            Telerik.Documents.ImageUtils.ImagePropertiesResolver defaultImagePropertiesResolver = new Telerik.Documents.ImageUtils.ImagePropertiesResolver();
            Telerik.Windows.Documents.Extensibility.FixedExtensibilityManager.ImagePropertiesResolver = defaultImagePropertiesResolver;
            var settings = new PdfExportSettings();
            settings.ImageQuality = ImageQuality.High;
            provider.ExportSettings = settings;
            provider.Export(document, memoryStream);
            // Return the byte array of the PDF
            outDocPdf = memoryStream.ToArray();
            //return memoryStream.ToArray(); // Return the byte array of the signed PDF
        }
    }
}
       private static double CalculateFontSize(double textWidth, double signatureFieldHeight, string text)
       {
           // Start with a base font size for better precision
           double baseFontSize = 12.0;  // Starting font size

           // Calculate width scale factor to adjust the font size based on text length
           double widthScaleFactor = textWidth / text.Length;
           double widthFontSize = baseFontSize * widthScaleFactor;

           // Calculate height scale factor to adjust the font size based on the number of lines
           int numLines = text.Split('\n').Length;
           double heightScaleFactor = signatureFieldHeight / (numLines * baseFontSize);
           double heightFontSize = baseFontSize * heightScaleFactor;

           // Return the smaller font size to fit both dimensions
           return Math.Min(widthFontSize, heightFontSize);
       }

       public static Tuple<double, double> calculateAspectRatioFit(double srcWidth, double srcHeight, double maxWidth, double maxHeight)
       {
           var ratio = Math.Min(maxWidth / srcWidth, maxHeight / srcHeight);
           return new Tuple<double, double>(srcWidth * ratio, srcHeight * ratio);
       }

firstly loading the document i have use 
  // Load the PDF document
  var provider = new PdfFormatProvider();
  var loadedDocument = provider.Import(inDocByte,null);

and after some functinality to export the document i have used below 

 Telerik.Documents.ImageUtils.ImagePropertiesResolver defaultImagePropertiesResolver = new Telerik.Documents.ImageUtils.ImagePropertiesResolver();
 Telerik.Windows.Documents.Extensibility.FixedExtensibilityManager.ImagePropertiesResolver = defaultImagePropertiesResolver;
 provider.Export(document, memoryStream, null);
 outDocPdf = memoryStream.ToArray();

what was the problem can you tell me the solution for that exception

Unable to cast object of type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfLiteralString' to type 'Telerik.Windows.Documents.Fixed.FormatProviders.Pdf.Model.Types.PdfName'.

the below method i got the exception i don't know what's wrong  can  anyone tell me 
the exception is occurred in below line 
  // Create PdfFormatProvider and load the existing document
 PdfFormatProvider pdfFormatProvider = new PdfFormatProvider();
 RadFixedDocument document = pdfFormatProvider.Import(inputStream);


static byte[] GenerateSignedPdf(Cert objCert, byte[] inDocByte)
{
    // Dimensions and positions for the signature field
    int signatureFieldWidth = 200; // Width of the signature field
    int signatureFieldHeight = 50;
    int signaturePositionLeft = 10;
    int signaturePositionTop = 10;

    // Load the certificate
    X509Certificate2 certificate = new X509Certificate2(objCert.CertArray, objCert.Password);

    // Create a SignatureField and assign the digital signature to it
    SignatureField pdfSignature = new SignatureField("SignatureField");
    pdfSignature.Signature = new Telerik.Windows.Documents.Fixed.Model.DigitalSignatures.Signature(certificate);

    // Set signature details
    string strNotAvailable = HttpContext.GetGlobalResourceObject("GlobalResources", "lblNotAvlbl").ToString();
    pdfSignature.Signature.Properties.Reason = strNotAvailable;
    pdfSignature.Signature.Properties.ContactInfo = strNotAvailable;
    pdfSignature.Signature.Properties.Location = strNotAvailable;

    // Load the existing PDF from the byte array using PdfFormatProvider
    using (MemoryStream inputStream = new MemoryStream(inDocByte))
    {
        // Create PdfFormatProvider and load the existing document
        PdfFormatProvider pdfFormatProvider = new PdfFormatProvider();
        RadFixedDocument document = pdfFormatProvider.Import(inputStream);

        // Create a new form to place the signature field
        Form pdfForm = new Form();
        pdfForm.FormSource = new FormSource();
        pdfForm.FormSource.Size = new Telerik.Documents.Primitives.Size(signatureFieldWidth, signatureFieldHeight);
        FixedContentEditor editor = new FixedContentEditor(pdfForm.FormSource);

        // Path to the image (ensure this is correct)
        var signatureImage = (System.Drawing.Image)HttpContext.Current.Session["imagesyncfusion"];

        // Drawing the image at the starting position (left side of the signature field)
        int imageWidth = signatureFieldWidth / 2;  // Half the width for the image
        int imageHeight = signatureFieldHeight;  // Use full height of the signature field

        // Create a memory stream to hold the image
        using (MemoryStream ms = new MemoryStream())
        {
            // Save the image to the memory stream
            signatureImage.Save(ms, signatureImage.RawFormat);

            // Reset the stream position to the beginning
            ms.Position = 0;

            // Pass the memory stream to the DrawImage method
            editor.DrawImage(ms, new Telerik.Documents.Primitives.Size(imageWidth, imageHeight));
        }

        string textToDraw = $"Digitally signed by {certificate.FriendlyName} \nDate: {DateTime.Now.ToString("yyyy.MM.dd HH:mm:ss zzz")} \nReason: {pdfSignature.Signature.Properties.Reason} \nLocation: {pdfSignature.Signature.Properties.Location}";
        // Set the width of the text area (remaining space after the image)
        int textWidth = signatureFieldWidth - imageWidth;
        double dsd = CalculateFontSize(textWidth - 23, signatureFieldHeight, textToDraw);

        // Now, draw the text next to the image (on the right side), within the remaining space
        Telerik.Windows.Documents.Fixed.Model.Editing.Block textBlock = new Telerik.Windows.Documents.Fixed.Model.Editing.Block();
        int textPositionLeft = signaturePositionLeft + imageWidth;  // Adding a 5px gap after the image
        textBlock.TextProperties.FontSize = dsd;
        textBlock.InsertText($"Digitally signed by {certificate.FriendlyName}");
        textBlock.InsertText($" Date: {DateTime.Now.ToString("yyyy.MM.dd HH:mm:ss zzz")}");
        textBlock.InsertText($" Reason: {pdfSignature.Signature.Properties.Reason}");
        textBlock.InsertText($" Location: {pdfSignature.Signature.Properties.Location}");
        Rect boundingRect = new Rect(textPositionLeft - 8, signaturePositionTop - 12, textWidth, signatureFieldHeight);
        textBlock.Draw(editor, boundingRect);

        // Create the SignatureWidget and position it on the PDF page
        SignatureWidget signatureWidget = pdfSignature.Widgets.AddWidget();
        signatureWidget.Content.NormalContentSource = pdfForm.FormSource;
        signatureWidget.Rect = new Rect(signaturePositionLeft, signaturePositionTop, signatureFieldWidth, signatureFieldHeight);
        signatureWidget.RecalculateContent();

        // Add content from the form to the page at the specified position
        RadFixedPage pdfPage = document.Pages[0];  // Assuming you're adding it to the first page
        FixedContentEditor pageEditor = new FixedContentEditor(pdfPage);
        pageEditor.Position.Translate(signaturePositionLeft, signaturePositionTop);
        pageEditor.DrawForm(pdfForm.FormSource);

        // Add the signature field to the document's AcroForm
        document.AcroForm.FormFields.Add(pdfSignature);

        // Use MemoryStream to capture the PDF output and return as a byte array
        using (MemoryStream memoryStream = new MemoryStream())
        {
            // Export the document to the memory stream as a PDF
            pdfFormatProvider.Export(document, memoryStream);
            return memoryStream.ToArray(); // Return the byte array of the signed PDF
        }
    }
}