Modifier les balises de fichier PDF

Les PDFs balisés sont conçus pour garantir l’accessibilité en marquant chaque élément—tel que le texte, les images et les liens—avec des balises qui définissent leur but et leur rôle dans le document. Lors de la modification de ces PDFs, il est crucial de préserver ces balises pour maintenir la conformité avec les normes d’accessibilité telles que le WCAG.

Des outils comme Aspose.PDF for .NET offrent une fonctionnalité robuste pour gérer le contenu balisé, mais il faut veiller à respecter la structure et l’accessibilité du document. En ajoutant méthodiquement du texte alternatif aux images ou en formatant des paragraphes, les PDFs balisés restent accessibles et conviviaux.

Depuis la version 24.7, dans le cadre de l’édition de PDF balisé, des méthodes ont été ajoutées sur Aspose.Pdf.LogicalStructure.Element :

Tag (ajouter des balises à des opérateurs spécifiques comme les images, le texte et les liens).
InsertChild.
RemoveChild.
ClearChilds.

Ces méthodes vous permettent de modifier les balises de fichier PDF, par exemple :

.NET Core 3.1

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void EditTags()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_WorkingDocuments();

    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "EditTags.pdf"))
    {
        // Get first page 
        var page = document.Pages[1];
        // The marked content operator on page for the image.
        Aspose.Pdf.Operators.BDC imageBdc = null;
        // The marked content operator on page for the text.
        Aspose.Pdf.Operators.BDC text1BDC = null;
        // The marked content operator on page for the link1.
        Aspose.Pdf.Operators.BDC link1Bdc = null;
        // The marked content operator on page for the link2.
        Aspose.Pdf.Operators.BDC link2Bdc = null;
        // The marked content operator on page for the Hello text.
        Aspose.Pdf.Operators.BDC helloBdc = null;
        // Find the marked content operators for the elements on the page.
        for (int i = 1; i <= page.Contents.Count; i++)
        {
            Aspose.Pdf.Operator op = page.Contents[i];
            var bdc = op as Aspose.Pdf.Operators.BDC;
            if (bdc != null)
            {
                // The text operator with marked content id = 0 was found.
                if (bdc.Properties.MCID == 0)
                {
                    helloBdc = bdc;
                }
            }

            var doXobj = op as Aspose.Pdf.Operators.Do;
            if (doXobj != null)
            {
                // Wrap the image XObject with makred content operator.
                imageBdc = new Aspose.Pdf.Operators.BDC("Figure");
                page.Contents.Insert(i - 2, imageBdc);
                i++;
                page.Contents.Insert(i + 1, new Aspose.Pdf.Operators.EMC());
                i++;
            }

            var tx = op as Aspose.Pdf.Operators.TextShowOperator;
            if (tx != null)
            {
                // Wrap the text operator on page with makred content operator.
                if (tx.Text.Contains("efter Ukendt forfatter er licenseret under"))
                {
                    text1BDC = new Aspose.Pdf.Operators.BDC("P");
                    page.Contents.Insert(i - 1, text1BDC);
                    i++;
                    page.Contents.Insert(i + 1, new Aspose.Pdf.Operators.EMC());
                    i++;
                }
                // Wrap the text operator on page with makred content operator.
                if (tx.Text.Contains("CC"))
                {
                    link1Bdc = new Aspose.Pdf.Operators.BDC("Link");
                    page.Contents.Insert(i - 1, link1Bdc);
                    i++;
                    page.Contents.Insert(i + 1, new Aspose.Pdf.Operators.EMC());
                    i++;
                }
                // Wrap the text operator on page with makred content operator.
                if (tx.Text.Contains("Dette billede"))
                {
                    link2Bdc = new Aspose.Pdf.Operators.BDC("Link");
                    page.Contents.Insert(i - 1, link2Bdc);
                    i++;
                    page.Contents.Insert(i + 1, new Aspose.Pdf.Operators.EMC());
                    i++;
                }
            }
        }

        Aspose.Pdf.Tagged.ITaggedContent tagged = document.TaggedContent;

        // Find exist struct element in document.
        Aspose.Pdf.LogicalStructure.Element helloParagraph = tagged.RootElement.ChildElements[1];

        // Clear the subtree of an existing structure tree element.
        helloParagraph.ClearChilds();

        // Tag paragraph struct element to text on page.
        Aspose.Pdf.LogicalStructure.MCRElement helloMCR = helloParagraph.Tag(helloBdc);

        // Get the struct element attributes.
        Aspose.Pdf.LogicalStructure.StructureAttributes helloAttrs = helloMCR.ParentStructureElement.Attributes.CreateAttributes(Aspose.Pdf.LogicalStructure.AttributeOwnerStandard.Layout);

        // Fill the paragraph struct element spaceAfter attribute.
        var helloSpaceAfter = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.SpaceAfter);
        helloSpaceAfter.SetNumberValue(30.625);
        helloAttrs.SetAttribute(helloSpaceAfter);

        // Create a figure element and place it to root element in second position.
        Aspose.Pdf.LogicalStructure.FigureElement figure = tagged.CreateFigureElement();
        tagged.RootElement.InsertChild(figure, 2);

        // Set an alternative text for the figure.
        figure.AlternativeText = "A fly.";

        // Tag figure struct element to image element on page.
        Aspose.Pdf.LogicalStructure.MCRElement figureMCR = figure.Tag(imageBdc);

        // Get the figure struct element attributes.
        Aspose.Pdf.LogicalStructure.StructureAttributes figureAttrs = figureMCR.ParentStructureElement.Attributes.CreateAttributes(Aspose.Pdf.LogicalStructure.AttributeOwnerStandard.Layout);

        // Fill the figure struct element spaceAfter attribute.
        var figureSpaceAfter = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.SpaceAfter);
        figureSpaceAfter.SetNumberValue(3.625);
        figureAttrs.SetAttribute(figureSpaceAfter);

        // Fill the figure struct element BBox attribute.
        var figureBBox = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.BBox);
        figureBBox.SetArrayNumberValue(new double?[] { 71.9971, 375.839, 523.299, 714.345 });
        figureAttrs.SetAttribute(figureBBox);

        // Fill the figure struct element placement attribute.
        var figurePlacement = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.Placement);
        figurePlacement.SetNameValue(Aspose.Pdf.LogicalStructure.AttributeName.Placement_Block);
        figureAttrs.SetAttribute(figurePlacement);

        // Find exist struct element in document.
        Aspose.Pdf.LogicalStructure.Element p2 = (Aspose.Pdf.LogicalStructure.StructureElement)tagged.RootElement.ChildElements[3];

        // Clear the subtree of an existing structure tree element.
        p2.ClearChilds();

        // Create the span struct element.
        Aspose.Pdf.LogicalStructure.SpanElement span1 = tagged.CreateSpanElement();

        // Get the span1 struct element attributes.
        Aspose.Pdf.LogicalStructure.StructureAttributes span1Attrs = span1.Attributes.CreateAttributes(Aspose.Pdf.LogicalStructure.AttributeOwnerStandard.Layout);

        // Fill the span1 struct element textDecorationType attribute.
        var span1TextDecorationType = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationType);
        span1TextDecorationType.SetNameValue(Aspose.Pdf.LogicalStructure.AttributeName.TextDecorationType_Underline);
        span1Attrs.SetAttribute(span1TextDecorationType);

        // Fill the span1 struct element textDecorationThickness attribute.
        var span1TextDecorationThickness = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationThickness);
        span1TextDecorationThickness.SetNumberValue(0);
        span1Attrs.SetAttribute(span1TextDecorationThickness);

        // Fill the span1 struct element textDecorationColor attribute.
        var span1TextDecorationColor = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationColor);
        span1TextDecorationColor.SetArrayNumberValue(new double?[] { 0.0196075, 0.384308, 0.756866 });
        span1Attrs.SetAttribute(span1TextDecorationColor);

        // Append the span element to the paragraph element in the struct tree.
        p2.AppendChild(span1);

        // Tag paragraph struct element to text element on page.
        Aspose.Pdf.LogicalStructure.MCRElement text1MCR = p2.Tag(text1BDC);

        // Get the mcr struct element attributes.
        Aspose.Pdf.LogicalStructure.StructureAttributes text1Attrs = text1MCR.ParentStructureElement.Attributes.CreateAttributes(Aspose.Pdf.LogicalStructure.AttributeOwnerStandard.Layout);

        // Fill the text1 MCR struct element textAlign attribute.
        var text1TextAlign = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextAlign);
        text1TextAlign.SetNameValue(Aspose.Pdf.LogicalStructure.AttributeName.TextAlign_Center);
        text1Attrs.SetAttribute(text1TextAlign);

        // Create the span struct element.
        Aspose.Pdf.LogicalStructure.SpanElement span2 = tagged.CreateSpanElement();

        // Get the span2 struct element attributes.
        Aspose.Pdf.LogicalStructure.StructureAttributes span2Attrs = span2.Attributes.CreateAttributes(Aspose.Pdf.LogicalStructure.AttributeOwnerStandard.Layout);

        // Fill the span2 struct element textDecorationType attribute.
        var textDecorationType = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationType);
        textDecorationType.SetNameValue(Aspose.Pdf.LogicalStructure.AttributeName.TextDecorationType_Underline);
        span2Attrs.SetAttribute(textDecorationType);

        // Fill the span2 struct element textDecorationThickness attribute.
        var textDecorationThickness = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationThickness);
        textDecorationThickness.SetNumberValue(0);
        span2Attrs.SetAttribute(textDecorationThickness);

        // Fill the span2 struct element textDecorationColor attribute.
        var textDecorationColor = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationColor);
        textDecorationColor.SetArrayNumberValue(new double?[] { 0.0196075, 0.384308, 0.756866 });
        span2Attrs.SetAttribute(textDecorationColor);

        // Append the span struct element to the struct element tree.
        p2.AppendChild(span2);

        // Create the link struct element.
        Aspose.Pdf.LogicalStructure.LinkElement link2 = tagged.CreateLinkElement();
        // Set an id attribute of struct element.
        link2.SetId(Guid.NewGuid().ToString());
        // Append the link struct element to the struct element tree.
        span2.AppendChild(link2);
        // Tag link struct element to the page annotation element.
        link2.Tag(page.Annotations[1]);
        // Tag link struct element to text element on page.
        link2.Tag(link2Bdc);

        // Create the link struct element.
        Aspose.Pdf.LogicalStructure.LinkElement link1 = tagged.CreateLinkElement();
        // Set an id attribute of struct element.
        link1.SetId(Guid.NewGuid().ToString());
        // Append the link struct element to the struct element tree.
        span1.AppendChild(link1);
        // Tag link struct element to the page annotation element.
        link1.Tag(page.Annotations[2]);
        // Tag link struct element to text element on page.
        link1.Tag(link1Bdc);

        // Remove the struct element at index 0 from the struct tree.
        tagged.RootElement.RemoveChild(0);

        // Save PDF document
        document.Save(dataDir + "EditTags_out.pdf");
    }
}

.NET 8

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void EditTags()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_WorkingDocuments();

    // Open PDF document
    using var document = new Aspose.Pdf.Document(dataDir + "EditTags.pdf");

    // Get first page
    var page = document.Pages[1];
    // The marked content operator on page for the image.
    Aspose.Pdf.Operators.BDC imageBdc = null;
    // The marked content operator on page for the text.
    Aspose.Pdf.Operators.BDC text1BDC = null;
    // The marked content operator on page for the link1.
    Aspose.Pdf.Operators.BDC link1Bdc = null;
    // The marked content operator on page for the link2.
    Aspose.Pdf.Operators.BDC link2Bdc = null;
    // The marked content operator on page for the Hello text.
    Aspose.Pdf.Operators.BDC helloBdc = null;
    // Find the marked content operators for the elements on the page.
    for (int i = 1; i <= page.Contents.Count; i++)
    {
        Aspose.Pdf.Operator op = page.Contents[i];
        var bdc = op as Aspose.Pdf.Operators.BDC;
        if (bdc != null)
        {
            // The text operator with marked content id = 0 was found.
            if (bdc.Properties.MCID == 0)
            {
                helloBdc = bdc;
            }
        }

        var doXobj = op as Aspose.Pdf.Operators.Do;
        if (doXobj != null)
        {
            // Wrap the image XObject with makred content operator.
            imageBdc = new Aspose.Pdf.Operators.BDC("Figure");
            page.Contents.Insert(i - 2, imageBdc);
            i++;
            page.Contents.Insert(i + 1, new Aspose.Pdf.Operators.EMC());
            i++;
        }

        var tx = op as Aspose.Pdf.Operators.TextShowOperator;
        if (tx != null)
        {
            // Wrap the text operator on page with makred content operator.
            if (tx.Text.Contains("efter Ukendt forfatter er licenseret under"))
            {
                text1BDC = new Aspose.Pdf.Operators.BDC("P");
                page.Contents.Insert(i - 1, text1BDC);
                i++;
                page.Contents.Insert(i + 1, new Aspose.Pdf.Operators.EMC());
                i++;
            }
            // Wrap the text operator on page with makred content operator.
            if (tx.Text.Contains("CC"))
            {
                link1Bdc = new Aspose.Pdf.Operators.BDC("Link");
                page.Contents.Insert(i - 1, link1Bdc);
                i++;
                page.Contents.Insert(i + 1, new Aspose.Pdf.Operators.EMC());
                i++;
            }
            // Wrap the text operator on page with makred content operator.
            if (tx.Text.Contains("Dette billede"))
            {
                link2Bdc = new Aspose.Pdf.Operators.BDC("Link");
                page.Contents.Insert(i - 1, link2Bdc);
                i++;
                page.Contents.Insert(i + 1, new Aspose.Pdf.Operators.EMC());
                i++;
            }
        }
    }

    Aspose.Pdf.Tagged.ITaggedContent tagged = document.TaggedContent;

    // Find exist struct element in document.
    Aspose.Pdf.LogicalStructure.Element helloParagraph = tagged.RootElement.ChildElements[1];

    // Clear the subtree of an existing structure tree element.
    helloParagraph.ClearChilds();

    // Tag paragraph struct element to text on page.
    Aspose.Pdf.LogicalStructure.MCRElement helloMCR = helloParagraph.Tag(helloBdc);

    // Get the struct element attributes.
    Aspose.Pdf.LogicalStructure.StructureAttributes helloAttrs = helloMCR.ParentStructureElement.Attributes.CreateAttributes(Aspose.Pdf.LogicalStructure.AttributeOwnerStandard.Layout);

    // Fill the paragraph struct element spaceAfter attribute.
    var helloSpaceAfter = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.SpaceAfter);
    helloSpaceAfter.SetNumberValue(30.625);
    helloAttrs.SetAttribute(helloSpaceAfter);

    // Create a figure element and place it to root element in second position.
    Aspose.Pdf.LogicalStructure.FigureElement figure = tagged.CreateFigureElement();
    tagged.RootElement.InsertChild(figure, 2);

    // Set an alternative text for the figure.
    figure.AlternativeText = "A fly.";

    // Tag figure struct element to image element on page.
    Aspose.Pdf.LogicalStructure.MCRElement figureMCR = figure.Tag(imageBdc);

    // Get the figure struct element attributes.
    Aspose.Pdf.LogicalStructure.StructureAttributes figureAttrs = figureMCR.ParentStructureElement.Attributes.CreateAttributes(Aspose.Pdf.LogicalStructure.AttributeOwnerStandard.Layout);

    // Fill the figure struct element spaceAfter attribute.
    var figureSpaceAfter = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.SpaceAfter);
    figureSpaceAfter.SetNumberValue(3.625);
    figureAttrs.SetAttribute(figureSpaceAfter);

    // Fill the figure struct element BBox attribute.
    var figureBBox = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.BBox);
    figureBBox.SetArrayNumberValue(new double?[] { 71.9971, 375.839, 523.299, 714.345 });
    figureAttrs.SetAttribute(figureBBox);

    // Fill the figure struct element placement attribute.
    var figurePlacement = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.Placement);
    figurePlacement.SetNameValue(Aspose.Pdf.LogicalStructure.AttributeName.Placement_Block);
    figureAttrs.SetAttribute(figurePlacement);

    // Find exist struct element in document.
    Aspose.Pdf.LogicalStructure.Element p2 = (Aspose.Pdf.LogicalStructure.StructureElement)tagged.RootElement.ChildElements[3];

    // Clear the subtree of an existing structure tree element.
    p2.ClearChilds();

    // Create the span struct element.
    Aspose.Pdf.LogicalStructure.SpanElement span1 = tagged.CreateSpanElement();

    // Get the span1 struct element attributes.
    Aspose.Pdf.LogicalStructure.StructureAttributes span1Attrs = span1.Attributes.CreateAttributes(Aspose.Pdf.LogicalStructure.AttributeOwnerStandard.Layout);

    // Fill the span1 struct element textDecorationType attribute.
    var span1TextDecorationType = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationType);
    span1TextDecorationType.SetNameValue(Aspose.Pdf.LogicalStructure.AttributeName.TextDecorationType_Underline);
    span1Attrs.SetAttribute(span1TextDecorationType);

    // Fill the span1 struct element textDecorationThickness attribute.
    var span1TextDecorationThickness = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationThickness);
    span1TextDecorationThickness.SetNumberValue(0);
    span1Attrs.SetAttribute(span1TextDecorationThickness);

    // Fill the span1 struct element textDecorationColor attribute.
    var span1TextDecorationColor = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationColor);
    span1TextDecorationColor.SetArrayNumberValue(new double?[] { 0.0196075, 0.384308, 0.756866 });
    span1Attrs.SetAttribute(span1TextDecorationColor);

    // Append the span element to the paragraph element in the struct tree.
    p2.AppendChild(span1);

    // Tag paragraph struct element to text element on page.
    Aspose.Pdf.LogicalStructure.MCRElement text1MCR = p2.Tag(text1BDC);

    // Get the mcr struct element attributes.
    Aspose.Pdf.LogicalStructure.StructureAttributes text1Attrs = text1MCR.ParentStructureElement.Attributes.CreateAttributes(Aspose.Pdf.LogicalStructure.AttributeOwnerStandard.Layout);

    // Fill the text1 MCR struct element textAlign attribute.
    var text1TextAlign = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextAlign);
    text1TextAlign.SetNameValue(Aspose.Pdf.LogicalStructure.AttributeName.TextAlign_Center);
    text1Attrs.SetAttribute(text1TextAlign);

    // Create the span struct element.
    Aspose.Pdf.LogicalStructure.SpanElement span2 = tagged.CreateSpanElement();

    // Get the span2 struct element attributes.
    Aspose.Pdf.LogicalStructure.StructureAttributes span2Attrs = span2.Attributes.CreateAttributes(Aspose.Pdf.LogicalStructure.AttributeOwnerStandard.Layout);

    // Fill the span2 struct element textDecorationType attribute.
    var textDecorationType = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationType);
    textDecorationType.SetNameValue(Aspose.Pdf.LogicalStructure.AttributeName.TextDecorationType_Underline);
    span2Attrs.SetAttribute(textDecorationType);

    // Fill the span2 struct element textDecorationThickness attribute.
    var textDecorationThickness = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationThickness);
    textDecorationThickness.SetNumberValue(0);
    span2Attrs.SetAttribute(textDecorationThickness);

    // Fill the span2 struct element textDecorationColor attribute.
    var textDecorationColor = new Aspose.Pdf.LogicalStructure.StructureAttribute(Aspose.Pdf.LogicalStructure.AttributeKey.TextDecorationColor);
    textDecorationColor.SetArrayNumberValue(new double?[] { 0.0196075, 0.384308, 0.756866 });
    span2Attrs.SetAttribute(textDecorationColor);

    // Append the span struct element to the struct element tree.
    p2.AppendChild(span2);

    // Create the link struct element.
    Aspose.Pdf.LogicalStructure.LinkElement link2 = tagged.CreateLinkElement();
    // Set an id attribute of struct element.
    link2.SetId(Guid.NewGuid().ToString());
    // Append the link struct element to the struct element tree.
    span2.AppendChild(link2);
    // Tag link struct element to the page annotation element.
    link2.Tag(page.Annotations[1]);
    // Tag link struct element to text element on page.
    link2.Tag(link2Bdc);

    // Create the link struct element.
    Aspose.Pdf.LogicalStructure.LinkElement link1 = tagged.CreateLinkElement();
    // Set an id attribute of struct element.
    link1.SetId(Guid.NewGuid().ToString());
    // Append the link struct element to the struct element tree.
    span1.AppendChild(link1);
    // Tag link struct element to the page annotation element.
    link1.Tag(page.Annotations[2]);
    // Tag link struct element to text element on page.
    link1.Tag(link1Bdc);

    // Remove the struct element at index 0 from the struct tree.
    tagged.RootElement.RemoveChild(0);

    // Save PDF document
    document.Save(dataDir + "EditTags_out.pdf");
}

Test de conformité PDF-UA - Liste des erreurs