Resolving missing content after HTML/DOCX to PDF conversion with WordsProcessing in .NET Standard

Environment

Version	Product	Author
2025.2.520	Telerik Document Processing	Desislava Yordanova

Description

When generating PDF files using RadWordsProcessing from HTML or DOCX templates, specific content may be missing in the output due to the fonts used in the document. This occurs because the .NET Standard version of RadPdfProcessing does not have a default mechanism to read fonts. To resolve this issue, the font data must be provided explicitly using the FixedExtensibilityManager and a custom implementation of the FontsProviderBase class.

This knowledge base article also answers the following questions:

• Why is some text missing in RadWordsProcessing-generated PDFs?
• How do I add support for custom fonts in RadPdfProcessing?
• How can I fix missing content in exported PDF files?

Solution

To ensure that custom fonts are correctly embedded in the PDF files:

1. Implement a FontsProvider: Create a custom class that inherits from FontsProviderBase and override the GetFontData method to provide the font data for the required fonts.

   Example implementation:

   internal class FontsProvider : Telerik.Windows.Documents.Extensibility.FontsProviderBase
   {
      private string fontFolder = Environment.GetFolderPath(Environment.SpecialFolder.Fonts);
   
      public override byte[] GetFontData(Telerik.Windows.Documents.Core.Fonts.FontProperties fontProperties)
      {
          string fontFamilyName = fontProperties.FontFamilyName;
          bool isBold = fontProperties.FontWeight == Telerik.Documents.Core.Fonts.FontWeights.Bold;
          if (fontFamilyName == "David")
          {
              fontFolder = @"..\..\..\";
              var fontData = this.GetFontDataFromFontFolder("David.ttf");
              fontFolder = Environment.GetFolderPath(Environment.SpecialFolder.Fonts);
              return fontData;
          }
   
          Debug.WriteLine($"Font not found: {fontFamilyName} (Bold: {isBold})");
          return null;
      }
   
      private byte[] GetFontDataFromFontFolder(string fontFileName)
      {
          using (FileStream fileStream = File.OpenRead(this.fontFolder + "\\" + fontFileName))
          {
              using (MemoryStream memoryStream = new MemoryStream())
              {
                  fileStream.CopyTo(memoryStream);
                  return memoryStream.ToArray();
              }
          }
      }
   }
   

2. Set the FontsProvider in FixedExtensibilityManager: Assign the custom FontsProvider implementation to the FontsProvider property of FixedExtensibilityManager.

   Telerik.Windows.Documents.Extensibility.FontsProviderBase fontsProvider = new FontsProvider();
   Telerik.Windows.Documents.Extensibility.FixedExtensibilityManager.FontsProvider = fontsProvider;
   

3. Ensure Font Availability: Download and include all necessary font files (e.g., David.ttf) used in your document. Place them in an accessible location relative to your application.

4. Rebuild and Run: Integrate the FontsProvider implementation into your application, rebuild, and test the PDF generation process. The previously missing content should now appear in the exported PDF files.

See Also

• Implementing FontsProvider
• Standard Fonts