After you modify a document you may want to get back information
about the objects you have added. For example you might want to
find out the natural dimensions of an image or you might want to
find out how many characters were drawn when you inserted some
text. This method allows you access to this information.
There are core information types that all objects support. There
are also information types specific to particular types of object.
You can use core information types to allow you to iterate through
every object in your document finding out specific information
about each of them.
If the object does not exist or does not support the requested
type of information then an empty string is returned.
Every object supports the ID and Type properties. For more
detailed information about this and other properties see the
section of this document.
PDF objects are case sensitive so be sure you use the correct
case when specifying information.