How to add interactivity to PDF documents using Actions

Introduction

In our latest post we’ve explored all possible ways to use links in PDF and promised to write an additional post about pdf actions. As you may recall, we used Destination objects for setting the targets of our links. Another way to get job done and extend the range of possible usages is to use Actions. They are described in section 12.6 “Actions” of the pdf specification and provide an alternative way to add interactivity to your documents.

In addition to jumping to a destination, actions can be used to launch application, execute Adobe JavaScript, play sound, change annotation’s appearance state, etc.

All available action types are listed below:

• GoTo - go to a destination in the current document
• GoToR - (“Go-to remote”) go to a destination in another document
• GoToE - (“Go-to embedded”) go to a destination in an embedded file
• Launch - launch an application, usually to open a file
• Thread - begin reading an article thread
• URI - resolve a uniform resource identifier
• Sound - play a sound
• Movie - play a movie
• Hide - set an annotation’s Hidden flag
• Named - execute an action predefined by the conforming reader
• SubmitForm - send data to a uniform resource locator
• ResetForm - set fields to their default values
• ImportData - import field values from a file
• JavaScript - execute a JavaScript code
• Rendition - controls the playing of multimedia content
• Trans - updates the display of a document, using a transition dictionary
• GoTo3DView - sets the current view of a 3D annotation

Actions can be assigned to annotations objects and outline items (“bookmarks”), see the code sample provided in the next section.

Code sample

Below is the slightly modified code sample from the post about links, its only difference is the use of Action object instead of Destination. It creates a bookmark and a link both having the same JavaScript action assigned. This action shows a simple message box with “hello world” message.

public void CreateLinkAndBookmarkWithJavaScriptAction()

{

    // create pdf document

    FixedDocument doc = new FixedDocument();

    // create javascript action, showing the message box

    Action action = new JavaScriptAction("app.alert('Hello world using 

        Apitron PDF Kit!');");

    // add a bookmark for second page

    doc.Bookmarks.AddFirst(new Bookmark(action, "JS Bookmark"));

    // add first page with text link

    Page firstPage = new Page();

    // add link text

    TextObject linkTextObject = new TextObject();

    linkTextObject.AppendTextLine("Click to execute JavaScript action");

    firstPage.Content.SaveGraphicsState();

    firstPage.Content.SetDeviceNonStrokingColor(RgbColors.Blue.Components);

    firstPage.Content.Translate(10, 820);

    firstPage.Content.AppendText(linkTextObject);

    firstPage.Content.RestoreGraphicsState();

    // add link annotation covering the text

    LinkAnnotation link = new LinkAnnotation(new Boundary(10, 815, 230, 835));

    link.BorderStyle = new AnnotationBorderStyle(0);

    link.Action = action;

    firstPage.Annotations.Add(link);

          

    // append pages

    doc.Pages.Add(firstPage);

    // save document

    using (Stream stream = File.Create("JavaScript_Action.pdf"))

    {

        doc.Save(stream);

    }

}

See the image below showing the results of clicking the link with assigned action.

Pic. 1 Bookmark and link with JavaScript action

It’s easy and simple as it should be. If you’d like to read more about Adobe’s JavaScript implementation, read the following book - “JavaScript™ for Acrobat® API Reference”.

Conclusion

As you can see, our product, Apitron PDF Kit for .NET, can be used to add interactivity to your pdf documents with unmatched ease and clearness. Using its API you’ll be able to:  create links, actions and bookmarks, create or modify pdf forms, and much more. Read our free book, or contact our support if you have any questions regarding its capabilities.

Downloadable version of this article can be found by the following link [PDF].