Kent Karlsson wrote: > Keyur Shroff wrote > [...] > > In Indic scripts any sign that appear in text not in > > conjunction with a > > valid consonant base may be rendered with dotted circle as fallback > > mechanism (Section 5.14 "Rendering Nonspacing Marks" > > http://www.unicode.org/uni2book/ch05.pdf). > > I don't know where you find support for that position in that text. > Can you please quote? There are no "invalid base consonants" for > any dependent vowel (for Indic scripts; similarly for any > other script).
Actually, there is a mention of displaying combining marks on dotted circles: "Several methods are available to deal with an unknown composed character sequence that is outside of a fixed, renderable set [...]. One method (Show Hidden) indicates the inability to draw the sequence by drawing the base character first and then rendering the nonspacing mark as an individual unit - with the nonspacing mark positioned on a dotted circle." (The Unicode Standard 3.0, page 120 - 5.14 Rendering Nonspacing Marks - Fallback Rendering) I add that this is a good way of displaying a combining mark that has no base character, i.e. one occurring at the begin of a line or paragraph. However, I totally agree with Kent that this funny rendering is *not* a requirement of the Unicode standard, as Keyur Shroff seems to suggest. It is just an example of many "several methods [that] are available to deal with" strange sequences. > > Any system implementing this as > > default behaviour should not be considered buggy. > > Indeed they are. And it should certainly not be default behaviour. In this case, I disagree with Kent: displaying these dotted circles is not mandatory, but certainly not a bug. > Any combining characters can be placed on any base characters without > there being any dotted circles displayed. True. But notice that Kent (against his own opinion) correctly wrote "can", not "must". > [...] _ Marco