On Mon, May 14, 2018 at 11:31 AM, Richard Wordingham via Unicode <[email protected]> wrote:
> ... One could argue that the three positions require > different glyphs for SIGN U. Each font would need its own PUA. Or a consensus. > ... There are several > places in Tai Tham layout where I want to swap glyphs round, but for > the layout engine to do so for me would cause grief for other Tai Tham > fonts. This rearrangement cannot be delegated to the rendering > engine. There are Tai Tham fonts which handle Indic rearrangement in > the ccmp feature, but they are then totally defeated by either ccmp not > being enabled or by the USE doing basic Indic shaping. Suppose the OpenType specs were revised to include a bit which could be set for disabling basic Indic shaping by the USE? I wouldn't set it if I were just starting out to make a font for a complex script requiring basic Indic shaping, and cannot imagine why anyone else just starting out would. > ... > > I think it would also help to make SIGN AA and SIGN TALL AA into > letters as far as the USE is concerned. The default grapheme > segmentation rules already treat them as consonants. The possible > downside is that so doing might mess up some fonts. The possibility of messing up some fonts has seldom (if ever) stopped needed revisions to shaping engines before. I should know. >> A good keyboard driver ... > > It won't work. The text input delivered by X still needs to be > supported, and without modifying the application, X can only input one > character at a time. Not everyone uses an 'input method'. Every keyboard uses a driver, though. I can't speak for "X", but my understanding is that the keyboard driver acts as sort of a buffer between the user's key strokes and the application. > Apparently, Hangul input should not be canonically normalised in South > Korea. I've seen an implementation of the USE render canonically > equivalent strings differently. ... Because the USE failed or because the font provided look-ups for each of those strings to different glyphs? Best regards, James Kass
