iText 7 PDF accessibility: “Table header cell has no associated subcells”

Question

I am converting HTML to a PDF using iText 7. I need the PDF to be accessible (508 compliant with appropriate tags, etc), but, no matter what markup I put on a table, accessi

Answer 1

After working with Jon Reilly on the iText team, this was the final solution that worked for me (column IDs and associated headers aren't needed... just Scope)

public class ThWithScopeTagWorker : ThTagWorker
{
    public ThWithScopeTagWorker(IElementNode element, ProcessorContext context) : base(element, context)
    {
    }

    public override void ProcessEnd(IElementNode element, ProcessorContext context)
    {
        base.ProcessEnd(element, context);
        IPropertyContainer elementResult = base.GetElementResult();
        if (elementResult is IAccessibleElement)
        {
            ((IAccessibleElement)elementResult).GetAccessibilityProperties().SetRole(StandardRoles.TH);

            //Can use this in the future in case we have th elements with different scope than "col"
            string htmlScope = element.GetAttribute("scope"); //This is the scope="XXX" in your HTML

            AccessibilityProperties properties = ((IAccessibleElement)elementResult).GetAccessibilityProperties();
            //Could add "Row" if needed based on htmlScope string above. 
            //For my purposes, all th elements were scope="col"
            properties.AddAttributes(new PdfStructureAttributes("Table").AddEnumAttribute("Scope", "Column"));
        }
    }

}

and this:

public class AccessibilityTagWorkerFactory : DefaultTagWorkerFactory
{
    public override ITagWorker GetCustomTagWorker(IElementNode tag, ProcessorContext context)
    {    
         //...        
        if (tag.Name() == "th")
        {
            return new ThWithScopeTagWorker(tag, context);
        }
        return base.GetCustomTagWorker(tag, context);
    }
}