From: John Hudson (tiro@tiro.com)
Date: Tue Nov 05 2002 - 10:14:29 EST
At 02:18 11/5/2002, William Overington wrote:
>Well, I suppose it depends upon what one means by a file format that
>supports Unicode. The TrueType format does not support the ZWJ method and
>thus does not "provide means to access unencoded glyphs by transforming
>certain strings of Unicode characters into them".
All three of the current 'smart font' formats are extensions of the
TrueType file format. Structurally, the only difference between a TrueType
font and an OpenType font is the presence of *optional* layout tables that
support glyph substitution and positioning. Officially, the only difference
is the presence of a digital signature.
>I am unsure as to
>whether, in formal terms, TrueType is "a file format that supports Unicode"
>as it does not allow the ZWJ sequences to be recognized.
Of course TrueType allows ZWJ sequences to be recognised. ZWJ is a
character that can appear in Unicode text and in the Unicode cmap of a
TrueType font. If a font does not contain a ligature for the sequence, or
does not contain layout information to render the sequence as a ligature,
the text is still processed according to the Unicode Standard, i.e. nothing
happens. To say that a font only supports Unicode if it can process and
render as a ligature every usage of the ZWJ character is foolish: every
font would have to contain glyphs and substitution lookups to support every
potential use of ZWJ in every possible
c+ZWJi+i+ZWJi+r+ZWJi+c+ZWJi+u+ZWJi+m+ZWJi+s+ZWJi+t+ZWJi+a+ZWJi+n+ZWJi+c+ZWJi+e.
That's even more moronic that saying that a font has to contain a glyph for
every character in Unicode in order to support the standard. It simply is
not true, and you're wrong. Again.
John Hudson
Tiro Typeworks www.tiro.com
Vancouver, BC tiro@tiro.com
It is necessary that by all means and cunning,
the cursed owners of books should be persuaded
to make them available to us, either by argument
or by force. - Michael Apostolis, 1467
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