Version: (using KDE Devel) Installed from: Compiled sources KDE/Qt currently only seem to support the following 3 OpenType features for Tibetan script: ccmp Composition / Decomposition blws Below Base Substitution abvs Above Base Substitution (see: <http://websvn.kde.org/trunk/qt-copy/src/gui/text/qscriptengine.cpp?revision=700774&view=markup> Ms Windows Uniscribe (USP.10) supports the following OpenType features: ccmp Composition Decomposition blws Below Base Substitution abvs Above Base Substitution calt Contextual Alternatives aalt access all alternatives blwm Below Base Mark Positioning abvm Above base Mark Positioning kern Kerning These features are applied in the order listed above. (All but calt and kern features are used in Microsoft's Himalaya font shipped with Win Vista. Both calt and kern are used in OFL'd Jomolhari Font and these features work with Uniscribe.) Pango now supports the following features for Tibetan: ccmp Composition / Decomposition locl Localized Forms blws Below Base Substitution abvs Above Base Substitution psts Post-base Substitutions clig Contextual Ligatures calt Contextual Alternative dist Distances blwm Below Base Mark Positioning abvm Above Base Mark Positioning kern Kerning Positioning mark Mark to base positioning mkmk Mark to mark Positioning (see: <http://svn.gnome.org/viewcvs/pango/trunk/modules/tibetan/tibetan-fc.c?view=markup&pathrev=2307>) ICU & OpenOffice.org support the following set of OpenType features for Tibetan <http://source.icu-project.org/repos/icu/icu/trunk/source/layout/TibetanReordering.cpp> has the following OT features defined for Tibetan script ccmp Composition / Decomposition blwf Below-base Forms pres Pre-base Substitutions blws Below Base Substitutions abvs Above Base Substitutions psts Post-base Substitutions blwm Below Base Mark Positioning abvm Above Base Mark Positioning dist Distance pref Pre-base Forms abvf Above base forms clig Contextual Ligatures mkmk Mark to mark positoning / attachment (see: <http://source.icu-project.org/repos/icu/icu/trunk/source/layout/TibetanReordering.cpp> ) =================================================== psts, pref, abvf, blwf and dist are probably redundant for Tibetan and they are not being used in any Tibetan fonts. While it is possible to make a Tibetan font that renders OK using only the GSUB features ccmp blws and abvs, some Tibetan fonts (e.g. Tib-US distributed by Radio Free Asia) rely heavily on the GPOS lookups blwm and abvm. Others e.g. Jomolhari use calt kern and kern to get ideal final shapes and positioning (The font renders legibly if these features fail be applied - but you get a less than ideal rendering.) Since Dzongkha l10n of KDE is now very actively taking place it would be nice to have support for these additional GPOS features added. - Chris Fynn (developer of Jomolhari & Tibetan Machine Uni fonts)
I'm quite sure product "i18n" is not very right place to ask it - as far as I remember Qt itself deals with OT fonts, so you should probably reassign the bug report to the product "kdelibs" and component "qt".
As far as I can see from other bug reports in component "qt" there is suggestion to report them directly to Trolltech (i.e. Qt developers). You can do it at http://trolltech.com/developer/bugreport-form Searching their task-tracker it seems Qt4 will be much better in handling OpenType...
please report this directly to qt-bugs@trolltech.com