ITEXT 7 Accessibility check Alternate Text

Question

How can I get the Accessibility, Alternate Text properties from a pdf using Itext 7 similar to what is displayed using Accessiblitiy tools link Adobe Pro?

Answer 1

You can access that information via the tag tree.

Set up your PDF document normally. You will need a new tag tree pointer.

string input = "input.pdf";
PdfReader reader = new(input);

PdfDocument document = new(reader);
Document pdf = new(document);

// This code is usually in its own method so we can get as many as we need
// Get the tag pointer at the root tag
TagTreePointer original = pdf.GetPdfDocument().GetTagStructureContext().GetAutoTaggingPointer().MoveToRoot();
// Get the element for the pointer. We use this to make a new pointer
PdfStructElem elem = original.GetContext().GetPointerStructElem(original);
// Return a new pointer using the element
var pointer = original.GetContext().CreatePointerForStructElem(elem);

You can reuse a pointer, but I find it helpful to get a new one for each operation.

Next, move to the tag you want to examine. For simplicity we'll use the first child.

// Move to first child (assuming one exists)
pointer.MoveToKid(0);

Now we can view the tag's properties.

// view data
pointer.GetProperties().GetActualText();
pointer.GetProperties().GetAlternateDescription();
pointer.GetProperties().GetStructureElementId();
// title is a bit more complicated. We have to use the low-level pdf struct and view the T (title) attribute
pointer.GetContext().GetPointerStructElem(pointer).GetPdfObject().GetAsString(PdfName.T);

You will want to write code to handle null values and tags.