Mars:FAQ
From Adobe Labs
Mars FAQ
What is Mars?
Mars is the code name for a project developing an XML-based representation of PDF documents. XML, Extensible Markup Language, is a cross-platform, extensible, and text-based standard for representing data of all kinds. PDF, Portable Document Format, is the global standard to reliably view, print, and share documentation over the web and with other people, regardless of a computer's operating system. PDF preserves all of the fonts, formatting, colors, and graphics of any source document.
Why Mars?
The Mars project was initiated to explore how XML and similar open standards could be used in ways that enable more developers to better integrate a PDF into existing and future applications and solutions. The Mars project has been hosted on Adobe Labs so that developers can review, participate and provide feedback on the development of the Mars technology. Already eager to receive feedback, the Mars project wiki will be staffed by the Mars development team.
Who should use Mars?
Mars supports developers who want to leverage their XML tools and knowledge to create, manipulate and extract information from PDF documents. It also provides an XML document solution for organizations that have chosen to unify their infrastructure using XML as the base representation. Architects and developers working on enterprise integration solutions or AJAX web applications should definitely take a look at the Mars technology. Those working on document generation and conversion, data extraction and integration, form generation and publishing projects should be closely following the Mars project.
What technologies can I leverage with Mars?
Mars interoperates with XML and standards-based formats allowing application developers to leverage existing knowledge of XML-based technologies. Enterprises deploying J2EE or SOA architectures should be sure to have an architect review and monitor the progress of the Mars technology.
How does Mars relate to PDF?
Mars documents, like PDF documents, can be displayed within a viewer application. When viewed, Mars documents have similar appearance and behavior as a PDF document with similar content. Other than having a different file suffix, an end user would not see any difference between a Mars document and a PDF document. However, if you look under the hood, a document created in the Mars format will appear different, containing XML components that enable some exciting enterprise use cases. With the Mars plug-in, Adobe Reader and Acrobat 8 can open, display, and operate on Mars documents.
How is a Mars document created?
Mars documents can be created by using XML components representing pages and the overall document structure and then combining them in a Zip package using off-the-shelf XML and ZIP tools. In addition, with the Mars plug-in and Acrobat 8, you can save PDF documents in Mars format. The Mars plug-in to create and view a Mars document will be available on Adobe Labs (in December). Additional documentation will be available on the Mars Labs Wiki site.
Can I convert between Mars format and PDF format?
Yes. They contain equivalent information and Acrobat 8 with the Mars plug-in can open both formats and Save-as the other format. To put it technically, Mars and today’s PDF are two serializations of the same infoset. Mars uses ZIP and XML as basic building blocks, while today’s PDF uses structures called “Cos” and “streams” as basic building blocks.
So what does Mars look like under the hood?
The information in a Mars document is organized similar to a PDF document. Mars represents document information by combining standard XML, images, fonts, and color formats within a Zip-based package. Page content is represented in SVG. In Mars, the pages, images, fonts, bookmarks, and other document components appear as separate files within the Zip package. The Mars components such as bookmarks are easier to manipulate by virtue of their XML representation.
Much like a web page which consists of a number of separate files referenced by a “root” HTML file, a Mars document consists of many file packaged together in a Zip file. There is a root "backbone.xml" file that references other files in the document.
What advantages does SVG bring to a Mars document?
SVG is an abbreviation for Scalable Vector Graphics, an XML-based, W3C standard language for describing graphics. Many applications and tools can create or manipulate SVG page contents. SVG page content can also be converted to PDF graphic operators using Acrobat 8.0 Professional and the Mars plug-in.
Is SVG animation and scripting supported?
PDF defines a model for scripting and interaction and that is used in Mars documents. PDF graphic content represents static documents so features of SVG related to dynamic graphics or interaction are not supported.
How are high-end print features supported in SVG?
Where SVG does not have sufficient function to support capabilities in PDF, private namespace extensions have been added. Over time, it is hoped that these features will be incorporated into the SVG standard.
What are some example workflows that integrate Mars documents?
The many possible workflows involving Mars documents include creation of Mars using XML tools and then converting to PDF for distribution and processing, conversion of PDF to Mars for use as a template, conversion of PDF to Mars for archiving, and later opening the Mars or conversion back to PDF. All of these workflows are made easy by use of XML and HTML-like references between document components.
Can an XML friendly file format also be speedy?
Mars documents are structured so that it is not necessary to load all of the components in the Zip package into memory ahead of time. With a Mars document, only the information required to perform a particular operation is read. Breaking the document into separate components provides a mechanism for efficiently accessing parts of the document. Each Mars component represents a separate entry point into the overall document that can be read independently of other content, thus, simplifying processing.
What are some advantages to an application processing a Mars document?
Mars enables improved manipulation of auxiliary content by allowing an application to more easily create and manipulate annotations, bookmarks, JavaScript, fonts, metadata, external references, specialized processing data, and attachments. Mars also improves upon document assembly and disassembly by simplifying the page-level assembly of documents. Mars also uses SVG, an industry graphics standard, to display page content.
What is the transition or compatibility between a mars pdf and an xfa pdf?
XFA (dynamic) forms provide advanced capabilities around forms and processing XML forms data. As XFA is part of PDF, it is a corresponding part of Mars. Much like Mars does for other PDF features, Mars make access to XFA components of a PDF easier.
Does Adobe LiveCycle support this?
The next release of Adobe LiveCycle plans to support server-side conversion between Mars format and PDF. Additional capabilities are in the works for future releases.
Can an end-user create a Mars document?
Anyone over the age of 18, or minors with parental permission, can create a Mars document.
How can an end-user view a Mars document?
With one of the plug-ins from Adobe Labs, Adobe Acrobat 8 and Reader 8 users can open and view Mars documents. Additionally, Acrobat 8 can be used to save a Mars document as a PDF document or vice versa.
Where can I find documentation and sample files?
Documentation is located at: http://labs.adobe.com/wiki/index.php/Mars
Is the Mars format frozen?
No. Mars is in a public evaluation period and we are actively looking for outside comment and suggestions.
If I save documents in Mars format today, will they continue to open forever as it does for PDF?
Mars is in an evaluation period and format changes based on public comment is expected. In order to engage with the PDF community on finalizing the details of the format and be able to incorporate their comments, the "opens forever" promise won’t be made until the format reaches a 1.0 release.
When will the Mars format be frozen for 1.0?
A date for this has not yet been set.
How do I send suggestions, comments, and bug reports?
Enter your suggestions, comments and bug reports in the Discussion area of the Mars wiki: http://labs.adobe.com/wiki/index.php/Talk:Mars .
When will the Mars plug-in be available?
It is planned to be available before the end of the year.
