Philippe asked: > The "Arial Unicode MS" font does not have a glyph for the Rial currency sign > so I won't comment lots about it, even if it's a special ligature of its > component letters:
> it's just regrettable that it's > not found in Arial Unicode MS (unless this Rial sign is traditional and no > more in actual use today). The Rial currency sign was recently added to the standard, so many fonts still don't have it. It was added for compatibility with an Iranian standard. > I'm not sure that the compatibility decomposition gives the accurate form > for rendering the traditional glyph coded for the currency symbol... It isn't supposed to. Compatibility decompositions are approximations, not necessarily the basis for building an Arabic ligation, especially for special cases like this currency sign. > FDFA;ARABIC LIGATURE SALLALLAHOU ALAYHE WASALLAM;0; > FDFA;<isolated> 0635 0644 0649 0020 0627 0644 0644 0647 0020 0639 > 0644 064a 0647 0020 0648 0633 0644 0645; > FDFB;ARABIC LIGATURE JALLAJALALOUHOU;0; > FDFB;<isolated> 062c 0644 0020 062c 0644 0627 0644 0647; > but the current presentation of > the alternate glyph chosen in Arial Unicode MS does not seems intuitive. That's an issue for Microsoft customers and testers of Microsoft fonts to determine. > Isn't there some requirement in Unicode to not change the common layout > which is part of the character identity and structural for the script? Such > interpretation problem does not occur in the presentation of U+FDFB (which > also has two rows in the representative glyph of Arabic Presentation Forms-A > charts). Is there an error here? Nope. Glyph shapes are not normative or prescriptive. As long as the identity of the character is clear, there might be an aesthetic faux pas, but not an error or a failure of conformance to the standard. > More generally, my question is related to the allowed modification of > layouts for ligature glyphs in fonts: are they allowed, Yes. > and how could they > be acceptably be represented when the plain-text character is not > compatibility-decomposed but rendered with a single glyph... By the code points in question, of course. For these word ligatures, which are really used as complete symbols, one would ordinarily not expect to enter the whole compatibility sequence of characters, anyway. Normal rendering engines don't produce these highly elaborated ligatures automatically from such sequences. > I was just wondering if their rendering in Arial Unicode MS is correct and > conforming to the required need to keep the interpretation, As long as the identity of the character is correct, which it seems to be, since you identified it, then one can say the font is "correct". > and in what measure the beautiful ligatures found in Unicode > charts are normative, In no measure. > as there's a very large difference with what Arial Unicde MS does There are large differences between Arabic fonts for *all* of the Arabic characters in the standard -- not just these word ligature symbols. --Ken
