Thanks for your response. The reason I initially thought of using object numbers was because I thought that object numbers would get updated by conforming pdf writers. So that if changes are made to an object number, the object itself has it's number changed. Or vice versa if an object's number changes, any object numbers that correspond to it in the document are changed. I guess by your response that that is not the case.
To elaborate a little more about what I am doing, I am adding something similar to a watermark to specific pages and resizing the existing page content so that the watermark does not appear on top of the existing content. It is the fact that I am resizing the existing page content that I have chosen my design. If I wanted to do it differently I guess I could add the existing page content to a template, create a new page and stick the template on it and then add my watermark. But I think that alternative would be cumbersome to undo and the necessary steps to undo it would make the pdf too unlike the original. I have an interim solution. When I modify a page I am recording in the PieceInfo (for that page) that content has been prepended to the contents array. To undo my modifications all I need to do is read the marker in PieceInfo and nuke the first entry in the contents array. There are obvious risks with this approach but at least I can guarantee it works for PDFs that are not subsequently modified by other applications. -- View this message in context: http://itext-general.2136553.n4.nabble.com/Determining-the-indirect-reference-of-undercontent-or-overcontent-tp4656408p4656454.html Sent from the iText - General mailing list archive at Nabble.com. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ iText-questions mailing list iText-questions@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/itext-questions iText(R) is a registered trademark of 1T3XT BVBA. Many questions posted to this list can (and will) be answered with a reference to the iText book: http://www.itextpdf.com/book/ Please check the keywords list before you ask for examples: http://itextpdf.com/themes/keywords.php
