PDFlib 8 Windows COM/.NET Tutorial

3.6 Interactive Elements
Cookbook Code samples for creating interactive elements can be found in the interactive category of
the PDFlib Cookbook.
3.6.1 Links, Bookmarks, and Annotations
This section explains how to create interactive elements such as bookmarks, form
fields, and annotations. Figure 3.1 shows the resulting document with all interactive elements
that we will create in this section. The document contains the following interactive
elements:
> At the top right there is an invisible Web link to www.kraxi.com at the text
www.kraxi.com. Clicking this area will bring up the corresponding Web page.
> A gray form field of type text is located below the Web link. Using JavaScript code it
will automatically be filled with the current date.
> The red pushpin contains an annotation with an attachment. Clicking it will open
the attached file.
> At the bottom left there is a form field of type button with a printer symbol. Clicking
this button will execute Acrobat’s menu item File, Print.
> The navigation page contains the bookmark »Our Paper Planes Catalog«. Clicking
this bookmark will bring up a page of another PDF document.
In the next paragraphs we will show in detail how to create these interactive elements
with PDFlib.
Web link. Let’s start with a link to the Web site www.kraxi.com. This is accomplished in
three steps. First, we fit the text on which the Web link should work. Using the matchbox
option with name=kraxi we specify the rectangle of the text’s fitbox for further reference.
Second, we create an action of type URI (in Acrobat: Open a web link). This will provide
us with an action handle which subsequently can be assigned to one or more interactive
elements.
Third, we create the actual link. A link in PDF is an annotation of type Link. The action
option for the link contains the event name activate which will trigger the action, plus
the act handle created above for the action itself. By default the link will be displayed
Fig. 3.1
Document with interactive
elements
3.6 Interactive Elements 87