aKademy 2007: Text Layout Summit

aKademy 2007 hosted two mini-summits, one for Schools and Education and one for Text Layout. The Text Layout Summit was a true cross platform event, and followed from the one last year at the Gnome Summit. Text layout is a complex area requiring advanced knowledge of dozens of different writing methods. With funding from The Linux Foundation they brought together people from Pango, Qt, IBM ICU (Intl. Components for Unicode), SIL Graphite, Unifont.org, m17n, W3C and DejaVu. Getting the various widget sets to have the same high quality support for all scripts is a problem the summit hoped to solve. Read on for details of what they discussed.

Busy in the Summit

Much of the current work for standardising text layout in the free software world is going on in the HarfBuzz project, a joint effort with code from Qt and Pango.

Organiser Ed Trager said of what had been discussed "A number of brief updates and discussions were given (as outlined on the summit wrapup page), but the major focus of discussion was on insuring that the HarfBuzz architecture and API will comfortably support the needs that SIL Graphite presents. The Open Source SIL Graphite engine is at the current time, from a features perspective, the most advanced Text Layout Engine available anywhere and was designed to support minority scripts as well as major complex world scripts like Burmese and Khmer. Scripts not yet in Unicode are also supported. There is an informed belief, especially from the Graphite community of course, that only a few key architectural features will need to be added or provided in HarfBuzz in order to support SIL Graphite integration. (A similar feature set may be required for Apple's AAT technology support, and Lars Knoll of Trolltech has already stated that he intends for HarfBuzz to have AAT support)."

"Behdad Esfahbod (Redhat, Pango) and Simon Hausmann (Trolltech, Qt) provided verbal agreement at the meeting that they would, together with the SIL Graphite folks (Tim Eves and Sharon Correll, inter alia), provide the foundational infrastructure needed to support SIL Graphite in HarfBuzz. Eric Mader will also be looking to port his synthetic Arabic GSUB table support for non-OpenType fonts from ICU into HarfBuzz."

Other talks included Arne Gotje talking about CJK support, the revival of openfontlibrary.org a website to catalogue freely licenced fonts and Fontima, a library that can be used to make font selection widgets a better experience than just seeing one big list. Sharon Correll presented Graphite which aims to support many minority languages.

Promising as these developments are, there are still unsolved problems in the world of text layout, including the Pan-Unicode issue. Should one font include every character, or should we fix our tools to make it easier to load characters from different fonts? The issues were described in The Pan-Unicode Fonts talk by Ben Laenen of DejaVu Fonts.

Relaxing in Glasgow

Behdad Esfahbod of Pango said that "the true value of all this meetings and harfbuzz is the sharing of OpenType engine and shapers between Pango, Qt, m17n and eventually ICU". New work on HarfBuzz and Graphite appears to be continuing at a good pace and although we don't know when it will all be completed, cross platform text layout bliss does seem a genuine prospect in the not too distant future. Many thanks to Daniel Glassey and Ed Trager for organising the summit. There are some photos of the meeting and you can get the presentation slides and an audio recording of the summit, with video still to come.