1. Document Inspector
Since its earliest versions, PDF Clown has been shipped including a simple Swing-based proof of concept for viewing PDF file structures. Now that little fledgling is going to become a comprehensive tool for the visual editing of the structure of PDF files: PDF Clown Document Inspector. It was initially planned to be part of 0.1.2 version as a dedicated project within the PDF Clown distribution, but approaching the release deadline it wasn’t ready yet.
This tool conforms to the PDF model as defined by PDF Clown (see the diagram above), which adheres to the official PDF Reference 1.7/ISO 32000-1. This implies that a PDF file is represented through several concurrent views which work at different abstraction levels: Document view (document layer), File view (file/object layer, hierarchical) and XRef view (file/object layer, flat).
PDF Clown 