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Creating Accessible PDF Documents
Updated on Jun 3, 2026
| Minimum Version | Q3 2025 |
|---|---|
| Related Feature: | Accessibility Support |
The following example shows how to generate an accessible PDF document using Telerik Document Processing.
To take advantage of the accessibility feature, the document must be PDF/A-1a, PDF/A-2a, PDF/A-3a, or PDF/UA-1 compliant. To achieve this, set the PdfComplianceLevel and TaggingStrategy properties of the PdfFormatProvider PdfExportSettings accordingly.
RadFixedDocument offers a constructor that allows you to specify the AutoTag property value which is false by default. You can choose whether to build the StructureTree from scratch or leave the library to auto-tag the elements.
Refer to the PdfProcessing Accessibility Demo which shows how to create accessible PDF documents programmatically, ensuring compliance with standards such as PDF/UA by supporting features like tagged content, document structure, and metadata. Downloaded documents adhere to the selected compliance level.
In .NET Standard/.NET (Target OS: None) environments, fonts beyond the 14 standard ones require a FontsProvider implementation to be resolved correctly.
Creating Accessible PDF Documents and Building the StructureTree
When exporting the document, specify the TaggingStrategy so the document is not tagged automatically and uses the existing StructureTree:
C#
//Required for exporting images in .NET Standard
//Telerik.Documents.ImageUtils.ImagePropertiesResolver defaultImagePropertiesResolver = new Telerik.Documents.ImageUtils.ImagePropertiesResolver();
//Telerik.Windows.Documents.Extensibility.FixedExtensibilityManager.ImagePropertiesResolver = defaultImagePropertiesResolver;
RadFixedDocument fixedDocument = new RadFixedDocument(autoTag: false);
fixedDocument.DocumentInfo.Title = "Accessible Document Example";
fixedDocument.ViewerPreferences.ShouldDisplayDocumentTitle = true;
StructureElement documentStructureElement = fixedDocument.StructureTree.ChildElements.AddStructureElement(StructureTagType.Document);
StructureElement sectionStructureElement = documentStructureElement.ChildElements.AddStructureElement(StructureTagType.Section);
StructureElement paragraphStructureElement1 = sectionStructureElement.ChildElements.AddStructureElement("CustomParagraph", StructureTagType.Paragraph);
StructureElement paragraphStructureElement2 = sectionStructureElement.ChildElements.AddStructureElement(StructureTagType.Paragraph);
StructureElement figureStructureElement = sectionStructureElement.ChildElements.AddStructureElement(StructureTagType.Figure);
RadFixedPage fixedPage = fixedDocument.Pages.AddPage();
MarkedContent paragraphContainer1 = fixedPage.Content.AddMarkedContent();
TextFragment textFragment1 = paragraphContainer1.Content.AddTextFragment("Text fragment 1");
textFragment1.Font = FontsRepository.Courier;
textFragment1.Position.Translate(20, 20);
paragraphContainer1.StructureTag = paragraphStructureElement1;
paragraphStructureElement1.AlternateDescription = "Standard Paragraph in English";
paragraphStructureElement1.Language = "EN";
paragraphStructureElement1.ActualText = "Text fragment 1";
MarkedContent paragraphContainer2 = fixedPage.Content.AddMarkedContent();
TextFragment textFragment2 = paragraphContainer2.Content.AddTextFragment("Fragmento de texto 2");
textFragment2.Font = FontsRepository.Courier;
textFragment2.Position.Translate(20, 100);
paragraphContainer2.StructureTag = paragraphStructureElement2;
paragraphStructureElement2.Language = "ES";
paragraphStructureElement2.AlternateDescription = "Custom Paragraph in Spanish";
paragraphStructureElement2.ActualText = "Fragmento de texto 2";
MarkedContent imageContainer1 = fixedPage.Content.AddMarkedContent();
figureStructureElement.Language = "EN";
figureStructureElement.AlternateDescription = "Image of a Telerik Ninja";
figureStructureElement.ActualText = "Telerik Ninja logo";
var img = imageContainer1.Content.AddImage();
img.Position.Translate(100, 200);
img.ImageSource = new Telerik.Windows.Documents.Fixed.Model.Resources.ImageSource(
File.OpenRead(@"ProgressNinjas.png"));
imageContainer1.StructureTag = figureStructureElement;
figureStructureElement.AlternateDescription = "Progress Ninja";
PdfFormatProvider provider = new PdfFormatProvider();
PdfExportSettings settings = new PdfExportSettings();
provider.ExportSettings = settings;
settings.TaggingStrategy = TaggingStrategyType.UseExisting;
settings.ComplianceLevel = PdfComplianceLevel.PdfUA1;
string outputFilePath = "AccessibleDocument.pdf";
File.Delete(outputFilePath);
using (Stream output = File.OpenWrite(outputFilePath))
{
provider.Export(fixedDocument, output, TimeSpan.FromSeconds(10));
}
Process.Start(new ProcessStartInfo() { FileName = outputFilePath, UseShellExecute = true });
| PDF Accessibility Checker tool | Logical Structure |
|---|---|
 |  |
 |
Creating Accessible PDF Documents with Auto-Tagging
The following example shows how to add content to a PDF document and leave the PdfProcessing engine to build the StructureTree automatically:
C#
//Required for exporting images in .NET Standard
//Telerik.Documents.ImageUtils.ImagePropertiesResolver defaultImagePropertiesResolver = new Telerik.Documents.ImageUtils.ImagePropertiesResolver();
//Telerik.Windows.Documents.Extensibility.FixedExtensibilityManager.ImagePropertiesResolver = defaultImagePropertiesResolver;
RadFixedDocument fixedDocument = new RadFixedDocument(autoTag: true);
fixedDocument.DocumentInfo.Title = "Accessible Document Example";
fixedDocument.ViewerPreferences.ShouldDisplayDocumentTitle = true;
RadFixedPage fixedPage = fixedDocument.Pages.AddPage();
MarkedContent paragraphContainer1 = fixedPage.Content.AddMarkedContent();
TextFragment textFragment1 = paragraphContainer1.Content.AddTextFragment("Text fragment 1");
textFragment1.Font = FontsRepository.Courier;
textFragment1.Position.Translate(20, 20);
MarkedContent paragraphContainer2 = fixedPage.Content.AddMarkedContent();
TextFragment textFragment2 = paragraphContainer2.Content.AddTextFragment("Fragmento de texto 2");
textFragment2.Font = FontsRepository.Courier;
textFragment2.Position.Translate(20, 100);
MarkedContent imageContainer1 = fixedPage.Content.AddMarkedContent();
var img = imageContainer1.Content.AddImage();
img.Position.Translate(100, 200);
img.ImageSource = new Telerik.Windows.Documents.Fixed.Model.Resources.ImageSource(
File.OpenRead(@"ProgressNinjas.png"));
PdfFormatProvider provider = new PdfFormatProvider();
PdfExportSettings settings = new PdfExportSettings();
provider.ExportSettings = settings;
settings.TaggingStrategy = TaggingStrategyType.Build;
settings.ComplianceLevel = PdfComplianceLevel.PdfUA1;
string outputFilePath = "AccessibleDocumentAuto.pdf";
File.Delete(outputFilePath);
using (Stream output = File.OpenWrite(outputFilePath))
{
provider.Export(fixedDocument, output, TimeSpan.FromSeconds(10));
}
Process.Start(new ProcessStartInfo() { FileName = outputFilePath, UseShellExecute = true });