Peter Kirk scripsit: > I don't understand the specific issues here... But it does seem a rather > strange design principle that we should expect a text to be displayed > meaningfully even when the font lacks the glyphs required for proper > display.
The key term is "necessary". In the Indic scripts, it is a principle that any instance of a consonant with VIRAMA (the rough equivalent of schwa quiescens) followed in the same word by another consonant may be replaced by a ligature of those consonants. However, no ligature is actually mandatory, and which ligatures are customary depends on the particular script, the particular language (it's common for some languages to be written in more than one Indic script), and the particular time and place of writing. Using fewer ligatures than custom dictates makes the text look crude, but using too many may render it utterly illegible, since unfamiliar ligatures are often not recognizable at sight. Therefore, the Unicode Standard does not encode any Indic ligature, though it does specify general methods (involving ZWJ and ZWNJ) for requesting partial or complete ligatures or for prohibiting ligaturing (and using the explicit VIRAMA appropriate to the script). It is indeed very much a matter of the font, therefore, which ligatures are possible and which are not possible. Disclaimer: I'm no expert on this. These remarks don't apply in their full generality to Tibetan, and aren't applicable at all to Thai or Lao. -- One art / There is John Cowan <[EMAIL PROTECTED]> No less / No more http://www.reutershealth.com All things / To do http://www.ccil.org/~cowan With sparks / Galore -- Douglas Hofstadter
