HtmlSaveOptions.ExportFontResources property

Specifies whether font resources should be exported to HTML, MHTML or EPUB. Default is false.

public bool ExportFontResources { get; set; }


Exporting font resources allows for consistent document rendering independent of the fonts available in a given user’s environment.

If ExportFontResources is set to true, main HTML document will refer to every font via the CSS 3 @font-face at-rule and fonts will be output as separate files. When exporting to IDPF EPUB or MHTML formats, fonts will be embedded into the corresponding package along with other subsidiary files.

If ExportFontsAsBase64 is set to true, fonts will not be saved to separate files. Instead, they will be embedded into @font-face at-rules in Base64 encoding.

Important! When exporting font resources, font licensing issues should be considered. Authors who want to use specific fonts via a downloadable font mechanism must always carefully verify that their intended use is within the scope of the font license. Many commercial fonts presently do not allow web downloading of their fonts in any form. License agreements that cover some fonts specifically note that usage via @font-face rules in CSS style sheets is not allowed. Font subsetting can also violate license terms.


Shows how to define custom logic for exporting fonts when saving to HTML.

    Document doc = new Document(MyDir + "Rendering.docx");

    // Configure a SaveOptions object to export fonts to separate files.
    // Set a callback that will handle font saving in a custom manner.
    HtmlSaveOptions options = new HtmlSaveOptions
        ExportFontResources = true,
        FontSavingCallback = new HandleFontSaving()

    // The callback will export .ttf files and save them alongside the output document.
    doc.Save(ArtifactsDir + "HtmlSaveOptions.SaveExportedFonts.html", options);

    foreach (string fontFilename in Array.FindAll(Directory.GetFiles(ArtifactsDir), s => s.EndsWith(".ttf")))

/// <summary>
/// Prints information about exported fonts and saves them in the same local system folder as their output .html.
/// </summary>
public class HandleFontSaving : IFontSavingCallback
    void IFontSavingCallback.FontSaving(FontSavingArgs args)
        if (args.Bold) Console.Write(", bold");
        if (args.Italic) Console.Write(", italic");
        Console.WriteLine($"\nSource:\t{args.OriginalFileName}, {args.OriginalFileSize} bytes\n");

        // We can also access the source document from here.


        // There are two ways of saving an exported font.
        // 1 -  Save it to a local file system location:
        args.FontFileName = args.OriginalFileName.Split(Path.DirectorySeparatorChar).Last();

        // 2 -  Save it to a stream:
        args.FontStream =
            new FileStream(ArtifactsDir + args.OriginalFileName.Split(Path.DirectorySeparatorChar).Last(), FileMode.Create);

See Also