OOXML Gets Boring

by Alex Brown 28. October 2008 15:52

2008 has been an exciting year for document format standards. 2009 will, I predict, be rather more boring.

This at least is the conclusion I reached after attending the recent DII workshop organised by Microsoft – and if I say the event was boring I merely mean that we can confidently expect document formats to stop being the at the centre of a spectator sport, and start returning to the land of techies and standards wonks. Boring, but reassuringly so; for while the more slashdotty spectators may prefer the ya-boo exchanges that characterised 2008, for us techies and standards wonks, boring is good – even … exciting.

Boring includes discussion of such topics as:

  • The effect of hyphenation dictionaries and justification algorithms on line breaking, and the impact of these considerations on achieving reproducible documents across implementations
  • How to decide what the chief document archetypes were for spreadsheets, word-processing documents and presentations
  • The distinction between an erratum and an amendment for an IEC/ISO standard
  • How to assemble and administer a collection of representative documents for assessing implementation conformance
  • How to validate the semantic constraints inherent in an OOXML document
  • The trade-off between format-specific and generic document APIs
  • How to facilitate server-side document generation
  • The trade-off between user convenience and standards adherence
  • The quirks of string sharing in Excel
  • How to document the implementation decisions an application makes which imposing further constraints on the underlying XML
  • How to re-purpose legacy Authorware training materials into OOXML

All good solid stuff, laying the groundwork for the people who really matter in this process (and who perhaps have too often been overlooked) – the end users. Doug Mahugh has a further write-up and links to the presentations on his blog.

Granted, a few eyebrows were raising during one presentation (which has not appeared among the others) which gave a startling frank overview of the challenges Microsoft are anticipating in implementing ISO/IEC 29500, from sucky performance in the deserialision code in PowerPoint, to dumb mistakes in Ecma 376, to coping with the fact that under certain circumstances Office 2007 emits content which is invalid against the Ecma 376 schemas.

I found this last revelation truly heartening – Microsoft did not need to make it, and to date (so far as I am aware) nobody has “caught” Office 2007 emitting invalid XML content. Yet here was MS ’fessing up and asking about ways they could stop it happening in future. All software companies (not just Microsoft) need to have a plain-dealing up-front approach to publicising problems. Such an approach has benefitted the security landscape and will have big benefits for document processing and conformance (and yes, for interoperability too). It is good to see the seeds of such a mature approach – I look forward to seeing Microsoft make this information public soon, and to something equivalent starting up for non-Microsoft ODF implementers too, bearing in mind that (with apologies to Alexander Pope):

Whoever thinks a bug-free app to see,
Thinks what n'er was, nor is, nor e'er shall be.

So, Talking of Bugs and ODF …

ODF Table Test

I had prepared a moderately hard table rendering test to take to Redmond, reasoning that table rendering is a fair indicator of the state of a layout engine beyond a basic “text and headings” level. To create this test document at home perform the following steps:

  1. Create a 5x5 Table
  2. Number the cells starting at the top left and moving left-to-right, top-to-bottom until you reach number 25 at the bottom right
  3. Merge consecutive cells to achieve the result below (note I have also coloured the merged cells to make it easier to see what has happened).

Et voila, a table rendering test. Here is that table displayed in OpenOffice 2.4 (click to enlarge):

Now, let us see how OpenOffice’s version of the table opens with the SP2 beta for Word 2007:

Good – on the face of it, a mini triumph for interoperability. For comparison, I also tried to open the document with Google Docs:

Hmm  – notice the different rendering here. Most obviously, the yellow cell which combines the original cells 4, 9 and 14 does not span downward, whereas that is what wanted to achieve when we created the table.

Looking at the ODF source, everything appears to be in order. The top-most spanned cell is marked-up as follows

<table:table-cell table:style-name="Table1.A1"
    table:number-rows-spanned="3" office:value-type="string">
  <text:p text:style-name="Table_20_Contents">4 9 14</text:p>
</table:table-cell>

The number-rows-spanned="3" attribute specified the row-spanning correctly, and the spanned-into cells (not shown) are properly marked-up with <table:covered-table-cell/> elements as the ODF spec suggests. (Interesting note: at no point is the ODF spec explicit that row spanning operations apply downwards – I have come across XML table models – Arbortext’s for example - which specify that spans apply upwards, and it is theoretically open for an ODF implementation to chose to do that too. So much for interoperability!)

So I think here we can reasonably point the finger at Google Docs and say that its table renderer is faulty – these guys need to catch up with OpenOffice and Microsoft.

Curiously, opening this test file with an early version of OpenOffice.org (1.1.5) gives the same rendering error as today’s Google docs:

And so we have seen a minor failure of interoperability. Of course it might not be so minor if these documents contained more important information (financial or medical data, e.g.) and not just pretty colours. This test however, just scratches the surface – for a more thoroughgoing examination of the poor state of ODF interoperability, readers can turn to the recent study by Shah and Kesan (and no, OOXML does not emerge hugely better from this either).

Looking Forward

Achieving interoperability appears to be the new focus for both the developers and standardisers working on document formats. For ODF, OASIS has the new Open Document Format Interoperability and Conformance (OIC) TC to advance work in this area. Microsoft is not currently represented here, and it is to be hoped they might soon overcome their shyness and participate. After all, when Office 2007 SP2 ships, Microsoft Office will quickly become the predominant ODF implementation, and it is important everybody works together to ensure they improve conformance and interoperability, and that where the ODF specification is insufficient for this, feedback is returned to ODF’s custodians.

Microsoft too are evidently thinking about interoperability and several presentations at the DII workshop were concerned with work to build a repository of representative Office documents to provide input into conformance and interoperability testing processes. Such an initiative is useful, though ideally it should take place under the aegis of a standards committee (e.g.  OASIS or SC 34 / WG 4), to parallel the activities taking place for ODF.

There was indeed, plenty of corridor discussion about how the future standards arrangements for ODF and OOXML might be best organized. I was particularly pleased to meet Dennis Hamilton (aka Orcmid), a member of the OASIS ODF TC and secretary to the OIC TC there – and we had plenty of constructive discussions about the how the current impasse in ODF maintenance might best be negotiated. However, the immediate solution to that particular problem now lies above the reach of mere committee members like us; it is between the lawyers and officials of OASIS and JTC 1.

R&R

After the workshop finished, there was time before my midnight flight for some R&R. Doug Mahugh was good enough to indulge my confession to being a Frasier fan and give me a tour of Seattle (where he grew up). It was good too to take a break from document formats and discuss less controversial topics like the US election, the identity of Mini-Microsoft, and Kirk/Spock porn!

 

Alex and Lunar Orbiter
Me being shown Seattle culture (photo: Doug Mahugh)

[UPDATE: Jesper Lund Stocholm has also just blogged on the topic of ODF support in MS Office — highly recommended.]

[UPDATE 2: wifely perspective.]

Comments

10/29/2008 4:41:59 AM #

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10/31/2008 10:08:50 AM #

Gareth

I agree, boring is good.

On the development side, we experienced 'exciting' for a while, just working from the Ecma spec documents and having to implement everything ourselves.  Usually, there are Microsoft libraries or libraries from 3rd party vendors for this sort of thing.

So back with the Monarch 9 release in Feb 2007, all the code was our own.  It was lean and fast, but there is a certain risk in attempting a project like this if you are not a huge company with vast resources.

The key point for us as developers is the introduction, and the promised roadmap of the Open XML SDK.

Although not as performant as our own code, the benefits certainly outweigh that.

1. Throw a bunch of code over the side - no more maintenance/QA etc
2. Allow quicker innovation - high level API means less research, testing and drudgery of implementation
3. Interoperability - yes, the big one ;)  Although maybe not the top of everyone's list about how to achieve interoperability, in the real world, a de facto API is pretty much the No.1 empirical means to achieve this.  If everyone uses a small number of APIs, then the likelyhood of these documents working together is vastly increased, compared to ev eryone rolling their own.

I know a single API is not a possibility, since the MS API will only run on .NET, though maybe it would work on Mono also, leading to more OSs.  Still, a leading open source API will feature somewhere.

I seem to remember Rob Weir trying to encourage the open source people (wisely) to get working on developer tools for ODF.  That is essential.  The strange thing is that they look likely to come from Microsoft first.

One could say that it demeans standards, distilling them down to a few technologies that interpret and implement them and it may be that there are risks in having just a few shops where you can get your Open XML / ODF SDK fix, but if you don't do this, then you end up with the HTML/PDF nightmare where very few pages are even anywhere near the standard.

PDF is perhaps the worst, as most people *think* that PDF files conform to the standard.  Everyone and their dog writing their own bug-ridden PDF producers has meant all the interop has had to be implemented at the client side, in an IE style way.

I can only dream of how many developers Adobe have working on making the utter garbage that some of these things write render on screen.

All this could have been avoided with decent API's.  Adobe has one, via DataGraphics AFAIK, but it is very pricy.

So if you want boring, in terms of no surprises, then a set of solid APIs for Open XML and ODF will go a long way to achieving interoperability in the real world.  Fewer bugs and fewer throats to choke.

Gareth

Gareth United Kingdom |

10/31/2008 5:02:29 PM #

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11/3/2008 1:17:11 PM #

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