[B-Greek] UTF
James Tauber
jtauber at jtauber.com
Fri Jan 7 15:03:04 EST 2005
I deliberated over whether to respond to the whole list and decided to do so
- apologies for being off-topic but it's the source of some confusion on
this list so thought it would be helpful.
On 8/1/05 3:30 AM, "William Zeitler" <william at faithfulbible.com> wrote:
>> the term UTF (really there is UTF-7, UTF-8 and UTF-16) applies to document
>> encoding, not fonts.
>
> Actually, both. You need both the document and the font to use the same
> encoding schema (e.g. both the document and the font must agree that
> 04ff29bHEX == 'alpha with a rough breather'). If the document uses an
> encoding schema that doesn't match the font's, you get a mess.
You are confusing the character code with the encoding.
The Unicode spec says that alpha with rough breathing is at code point 7937
(i.e. 0x1F01 in hex)
This is the only mapping the font file itself needs to know.
However, when reading or writing a document, you (or rather, the editor you
are using) needs to decide how to represent that number 7937.
UTF-16 would represent it 1F 01 or 01 1F
UTF-8 would represent it E1 BC 81
The font doesn't need to know any of this - all it knows is alpha with rough
breathing is code point 7937. The character encoding UTF-8 decides that 7937
will, in a document, be expressed as E1 BC 81
Note also that this is all separate from keyboard mappings.
* A KEYBOARD MAPPING maps keys to characters
* A CODED CHARACTER SET (like Unicode) maps characters to numbers
* A CHARACTER ENCODING (like UTF-8) maps numbers to bytes in a file
> Even within Unicode there are different schemas (e.g. Normalization Form C
> vs. D, which are specifically concerned with diacritical marks).
Right. There is a difference between alpha with rough breathing and alpha +
rough breathing. Note that this distinction can exist in any coded character
set with diacritics whether Unicode or not. Also note that this is
orthogonal to the choice of character encoding.
James Tauber
More information about the B-Greek
mailing list