Adding Headers, Footers and Caption Text to DjVu files
An investigative report by PlanetDjVu, March 24, 2003
Adding Header, Footer and Caption text to DjVu files is a feature that made it's debut "way back" in 1999, when AT&T Labs introduced DjVu Version 2.0 and when Feith Data Systems, at the same time, introduced the DjVuer Pro application for Windows.
DjVuer Pro, which is still available from Feith (we think), lets you specify the position, size and fonts used in text that is added to the image layer of the DjVu page. There are a full range of of options for text placement, including orientation and the resizing of the page, if necessary, to accomodate the text.
These options are fully documented in the DjVuer Pro Help File.
Unfortunately, after DjVu format was acquired by LizardTech, Feith was unable to license DjVu from LizardTech, so DjVuer Pro was not upgraded beyond DjVu Version 2.0. Today, DjVuer Pro is (perhaps) the only application to write headers, footers and caption text into DjVu files, but it has little usefulness today since the Version 2.0 DjVu file format is now obsolete.
There are some indications that LizardTech may be working on support for adding text to DjVu files. The first indication came a year ago when LizardTech announced on their website that Headers and Footers could be added to DjVu files with the Document Express Desktop Edition product. Strangely, this support was not announced for the Document Express Professional Edition. Today, a year later, we have yet to see an example of a DjVu file that has headers and footers written in. Here is the page on which Headers and Footers are mentioned. This is the only known reference to this feature. In the absence of any other documentation, we assume it is still a "vaporware" feature.
Now there are new indications that LizardTech is implementating support for headers, footers and captions.
The first indication is on the LizardTech DjVu Browser Plugin download page, in which this statement is made:
The 4.0.0 version of the plug-in for Windows includes support for the enhanced annotation capability available in DjVu Editor 4.0 and DjVu Editor 4.0 (Pro).
The next indication is in the Readme.txt file that gets installed with the new plug-in upgrade, which mentions as new 4.0 features:
Support for new 4.0 version of annotations
Print v 4.0 Annotations
Then, in the help file for the 4.0 plug-in, this statement is made:
Embedding a document displays it as part of the HTML page and does not require that the Web server support the DjVu MIME types. This method also allows you to list captions and other annotations with the document.
The above is absolutely all the documentation we can find from LizardTech about this feature. So we are left with the following questions:
1. Does the term "annotations" as used by LizardTech include "headers" and "footers"? Does this term also encompass "captions"?
2. Are these written into the DjVu page image, or are they stored as annotation ASCII text? If stored as ASCII text, is the font also stored?
3. Why does embedding a DjVu file in HTML allow you to "list captuions and other annotations with the document"? What happens if the DjVu file is not embedded in HTML?
4. Does this support for annotations in Version 4.0 of the plug-in account for why the plug-in size has doubled?
5. We have not seen Headers and Footers demonstrated for a year. When can we expect to see these and Captions demonstrated?
6. In the absence of any document other than obscure and brief comments, is this all "vaporware"?
The list of questions could go on, but first there needs to be more basic information provided on which to form the questions!
Adding text to page images can be useful in many ways. Header and footer text can be added, watermarks can be added, captions can be added to pictures, and images can be Bates stamped for the legal profession.
When Feith Data Systems introduced the feature of adding text to DjVu files four years ago, it was fully documented and you knew immediately what you were getting and what you could do with the feature.
With LizardTech these days, it is a complete guessing game!
Can you add text to DjVu files today with DjVu software from LizardTech? Our most informed answer is "maybe". If so, then how is it done? How is it stored in the file? How is it displayed? We simply don't know. Neither does anyone at DjVuLibre (where the documentation of features is always perfectly clear).
We have heard an unconfirmed rumour that LizardTech is now using annotation support from LeadTools. You can read up on the LeadTools annotation SDK here. If LizardTech has indeed compiled the LeadTools SDK into the DjVu Browser Plugin now, this might explain why the plug-in doubled in size.
LeadTools Annotation objects can be stored as a separate object layer, or can be burned or embedded into the actual image. As we described above, the approach taken by the DjVuer Pro application in the past was to burn the annotations into the image.
When stored as a separate object layer, the LeadTools SDK defines the storage options for Annotations as: an external LEAD file, WMF file, or as a WANG compatible tag inside a TIFF file. It is also possible to save an object or group in a database using OLEDB or VB data binding.
LeadTools annotation objects could potentially be stored in the annotation chunk of a DjVu file, just as we already store embedded metadata, bookmark trees and CGI-Style Arguments in the annotation chunk of DjVu files in the completed but unreleased JRAPublish application today. The open design of the DjVu file format (specifically the annotation chunk) permits such innovations.
Once again, the use of LeadTools annotations in DjVu by LizardTech is just a rumour, and we are back to the guessing game again!