Date: Sat, 5 May 2012 14:35:14 +0100
The attached picture shows 16 box-drawing characters from Big5 (glyphs scanned from Lunde's CJKV Information Processing, 1st Edn).
The characters in the first line are found in Row A2, which is part of the original Big5:
a) A2-7E: U+256D (BOX DRAWINGS LIGHT ARC DOWN AND RIGHT)
b) A2-A1: U+256E (BOX DRAWINGS LIGHT ARC DOWN AND LEFT)
c) A2-A2: U+2570 (BOX DRAWINGS LIGHT ARC UP AND RIGHT)
d) A2-A3: U+256F (BOX DRAWINGS LIGHT ARC UP AND LEFT)
e') A2-A4
f') A2-A5
g') A2-A6
h') A2-A7
The characters in the second line are found in Row F9, which is part of an E-Ten extension to Big5 (included in many Big5 implementations including Microsoft's Big5 variant (Code Page 950) and the official Hong Kong standard Big5-HKSCS):
a') F9-FA
b') F9-FB
c') F9-FC
d') F9-FD
e) F9-F9: U+2550 (BOX DRAWINGS DOUBLE HORIZONTAL)
f) F9-E9: U+255E (BOX DRAWINGS VERTICAL SINGLE AND RIGHT DOUBLE)
g) F9-EA: U+256A (BOX DRAWINGS VERTICAL SINGLE AND HORIZONTAL DOUBLE)
h) F9-EB: U+2561 (BOX DRAWINGS VERTICAL SINGLE AND LEFT DOUBLE)
The double-stroked quarter circles (a', b', c', d') appear to be missing from Unicode. Have they been proposed for inclusion previously?
The four box-drawing characters e', f', g' and h' are more problematic: Row F9 includes a full set of box-drawing characters with two horizontal or vertical lines. Row A2 only includes a small subset set of four such characters (e'--h'), which differ from the corresponding characters in Row F9 (e--h) by having the two horizontal lines rather far apart. Might it be appropriate to register variation sequences for these?
This issue came to my attention again recently because of Anne van Kesteren's work on Web encodings (<http://dvcs.w3.org/hg/encoding/raw-file/tip/Overview.html>).
-- Řistein E. Andersen
