From: steve (firstname.lastname@example.org)
Date: Fri Jun 11 2010 - 14:39:39 CDT
Greetings Unicode List,
I'm working on a character encoding model for SignWriting. I just
finished the 3rd major revision. Instead of needing an entire plane, I
only need 1280 code points. Since 1024 code points have already been
tentatively reserved for SignWriting on the SMP (1d8 thru 1db), I'm very
happy with my latest update.
SignWriting is an unusual script because it does not follow the same
rules as other script. I do not believe SignWriting can be changed to
follow the same rules without breaking the script.
Before discussing the primary difference, I'd like to stipulate three
assumptions. First, sign languages are real human languages. Second,
sign language can be written. Third, SignWriting can write sign
We have an international user base. People write by hand or computer.
We have tens of thousands of signs in different sign languages from
around the world. We have hundreds of documents including "The Cat in
the Hat" (translated with permission), whole books of the Bible, and
others. All of this writing can be encoded using 1280 code points. I
have a 12-bit encoding with bi-directional conversion with UTF-8 working
for planes 1, 15, or 16. I'm currently using plane 15: fd800 thru
The primary difference between SignWriting and other scripts is that
SignWriting is a spatial script. The graphemes of SignWriting are not
written sequentially and do not have definable attachment points.
Imagine a two dimensional canvas. The graphemes can be written anywhere
on the canvas. A completed sign (or word) will consist of several
graphemes spatially arranged on a canvas. There is an infinite number
of signs that can be created.
A spatial script requires a coordinate system, either cartesian or
polar. I do not believe Unicode currently includes any spatial scripts,
but it is impossible to use SignWriting without a coordinate system.
The character encoding model is called Binary SignWriting and is
All of the graphemes of the script are documented and encoded.
I was hoping to start on the Unicode Proposal in the near future.
Any suggestions, comments or discussion is welcome.
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