In some cases, there are strict formal requirements with respect to a form.

It didnt matter if we were adding high-level objects (e.g.

Paragraph) or low-level instructions (e.g.

In this chapter, well add content of a different nature.

There are many different types of annotations, many of which allow user interaction.

The only difference is that we create and add an annotation.

PdfAnnotation ann new PdfTextAnnotation(new Rectangle(20, 800, 0, 0)).

We set the color, title (a PdfString), contents (a String), and the open status of the annotation.

We ask the PdfDocument for its first page and add the annotation.

Fortunately, we can wrap the link annotation in a Link object and iText will calculate the Rectangle automatically.

Paragraph p new Paragraph(The example of link annotation.

Click ).Add(link.SetUnderline()).Add( to learn more.).

This is a basic building block that accepts a link annotation as parameter.

This link annotation wont be added to the content stream, because annotations arent part of the content stream.

Instead it will be added to the corresponding page at the corresponding coordinates.

Making text clickable doesnt change the appearance of that text in the content stream.

PdfAnnotation annotation new PdfLineAnnotation(new Rectangle(0, 0), new float 20, 790, page.GetPageSize().GetWidth() - 20, 790 ).

PdfAnnotation ann PdfTextMarkupAnnotation.CreateHighLight(new Rectangle(105, 790, 64, 10), new float 169, 790, 105, 790, 169, 800, 105, 800 ).

Each form field in that form will correspond with a widget annotation, but those annotations will be created implicitly.

This technology was introduced in PDF 1.2 (1996) and allows you to populate a PDF document with form fields such as text fields, choices (combo box or list field), buttons (push buttons, check boxes and radio buttons), and signature fields.

When text doesnt fit into the available text area of an HTML form, that field can be resized.

The content of a list field can be updated on the fly based on a query to the server.

Such a form can best be compared with a paper form where every field has its fixed place and its fixed size.

The idea of using PDF forms for collecting user data in a web browser has been abandoned over the years.

HTML forms are much more user friendly for online data collection.

Interactive PDF forms are very common in two specific use cases.

Adding Checkbox In Pdf Using Itext