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RIT Malayalam fonts: supporting a range of OpenType shapers

Saturday, 6 July 2024 | Rajeesh K Nambiar


The open fonts for Malayalam developed by Rachana Institute of Technology use our independently developed advanced shaping rules since 2020. A conscious decision was made to support only the revised OpenType specification for Indic scripts (the script tag mlm2, which fixed issues with the v1 specification such as halant shifting). Our shaping rules provide precise, exact and definite shaping for Malayalam Unicode fonts on all major software platforms.

And yet, there are many users who still use either old or buggy softwares/platforms. Hussain and Bhattathiri have expressed angst and displeasure in seeing their beautifully and meticulously designed fonts not shaped correctly on some typeset works and prints (for instance, Ezhuthu is used by Mathrubhumi newspaper showing detached ു/ൂ-signs). I have received many requests over the years to add support for those obsolete (or sometimes proprietary) platforms, but have always refused.

Fig. 1: Ezhuthu font shaped with detached ൃ/ ു-signs. They should conjoin with base character. Source: Mathrubhumi.

Few weeks ago, CVR and I were trying to generate Malayalam epub content to read on a Kobo ebook reader (which supports loading user’s own fonts, unlike Kindle). We found that Kobo’s shaping software (quite possibly an old version of Pango) does not support the v2 OpenType specification. That did irk me and I knew it is going to be a rabbit hole. A little bit of reverse engineering and a day later, we were happy to read Malayalam properly shaped in Kobo, by adding rudimentary support for v1 spec.

Fig. 2: RIT Rachana shaped perfectly with Kobo ebook reader (ignore the book title).

Out of curiosity, I checked whether those small additions work with Windows XP, but it did not (hardly surprising). But now that the itch has been scratched; a bunch of shaping rules were added to support XP era applications as well (oh, well).

Fig. 3: RIT Rachana shaped perfectly in Windows XP.

Few days later, a user also reported (known) shaping issue with Adobe InDesign. Though I was inclined to close it as NOTABUG pointing to use HarfBuzz instead, the user was willing to help test a few attempts I promised to make. Adobe 2020/2021 (and earlier) products use Lipika shaper, but recent versions are using HarfBuzz natively. Lipika seems to support v2 OpenType specification, yet doesn’t work well with our existing shaping rules. Quite some reverse engineering and half a dozen attempts later, I have succeeded in writing shaping rules that support Lipika along with other shapers.

Fig.4: RIT Rachana shaped perfectly with InDesign 2021 (note: the characters outside margins is a known issue only with InDesign, and it is fixed with a workaround).

All published (and in progress) RIT Malayalam fonts are updated with these new set of shaping rules; which means all of them will be shaped exactly, precisely and correctly (barring the well-known limitation of v1 specification and bugs in legacy shapers ) all the way from Windows XP (2002) to HarfBuzz 8.0 (present day) and all applications in between.

Supported shaping engines

With this extra engineering work, RIT fonts now tested to work well with following shaping engines/softwares. Note: old Pango and Qt4 have shaping issues (with below base ല forms and ു/ൂ forms of conjuncts, in respective shapers), but those won’t be fixed. Any shaper other than HarfBuzz (and to a certain extent Uniscribe) is best effort only.

New releases

New releases are made available for all the fonts developed by Rachana Institute of Typography, viz.

Acknowledgements

A lot of invaluable work was done by Narayana Bhattathiri, Ashok Kumar and CV Radhakrishnan in testing and verifying the fonts with different platforms and typesetting systems.

End users who reported issues and helped with troubleshooting have also contributed heavily in shaping (pun intended) community software like RIT Malayalam open fonts.