On Sun, Feb 14, 2010 at 02:42:30PM +0100, Hans Hagen wrote: > On 13-2-2010 18:32, Khaled Hosny wrote: > >On Fri, Feb 12, 2010 at 07:21:14PM +0100, Hans Hagen wrote: > >>On 12-2-2010 19:03, Khaled Hosny wrote: > >>>Is 'opbd' feature supported? According to the spec[1] this feature is > >>>used to define what I think is equivalent to the protrusion values used > >>>for optical alignment of the glyphs. I grepped the sources and there > >>>seem no be special handling of it, I don't have fonts that use this > >>>feature (I didn't look for one) but I'm planning to use it in my fonts > >>>and thought I'd check if ConTeXt support it first. > >>> > >>>This Typophile thread[2] might be interesting too. > >>> > >>>If fonts are needed I can check for free fonts that implement this, or > >>>prepare a font for testing. > >>> > >>>[1] http://www.microsoft.com/typography/OTSPEC/features_ko.htm#opbd > >>>[2] http://typophile.com/node/48738 > >> > >>Indeed I need a test font in order to see how it can be implemented. > >>If there are no fonts we should wonder what the exact spec is. Does > >>fontforge support it? > > > >I found that the font "fxlbi.otf" (of libertine fonts) has both 'lfbd' and > >'rtbd' (left/right optical bounds) but no 'opbd' feature. Now re-reading > >the spec, I don't see what the values stored in 'opbd' is used for as > >the application has to consult 'lfbd' or 'rtbd' feature according to the > >position of the glyph in the line, I asked on OpenType mailing list but > >I don't expect getting an answer (nobody implemented this feature, except > >FontForge AFAIK.) My suggestion is to ignore 'opbd' completely and just > >use the values from 'lfbd'/'rtbd' directly. > > but are these [lr]fbd meant for protruding or for italic correction
They are meant for protruding, and per the spec should be applied only at the start/end of line. http://www.microsoft.com/typography/OTSPEC/features_ko.htm#lfbd http://www.microsoft.com/typography/OTSPEC/features_pt.htm#rtbd -- Khaled Hosny Arabic localiser and member of Arabeyes.org team Free font developer _______________________________________________ dev-context mailing list dev-context@ntg.nl http://www.ntg.nl/mailman/listinfo/dev-context
