On Nov 19, 2008, at 10:42 AM, Jungshik Shin (신정식, 申政湜)
wrote:
2008/11/6 Prunthaban Kanthakumar <[EMAIL PROTECTED]>
Now we can do the following,
1. Add an additional condition in styleDidChange method to check if
the font-family is supported by our transcoder (At present a fast
look-up table should do because we plan to support only limited set
of fonts) - This condition will be #ifdefed on
ENABLE(TRANSCODER_SUPPORT).
Shouldn't this be triggered by (font-family, site) rather than just
font-family?
Since we're looking at this as a legacy compatibility feature, and
would like future sites to move to proper Unicode-encoded text, my
first instinct would be {font, site} pairs. But that depends on
whether we can achieve acceptable Indic browsing results with just a
fixed list of sites.
On a related note, I would like to mention here that, we cannot go
with the approach of 'one look-up table' per font-face and a single
transcoder to do the look-up for all fonts. The problem is that many
indic languages use multiple code-points to represent one character
and different fonts use different standards! For example there are
situations where one glyph in EOT needs to be transcoded to 5+
Unicode code points. A reverse situation is also possible. Due to
these issues, we cannot go with a simple look-up table for all
fonts. This forces us to write some specialized code to handle each
font (there might also be some fonts where a one-to-one look-up
table will be enough).
In October, I listed two alternatives for this transformation. One
is adding ICU converters for Indic font encodings (it can deal with
m-to-n mappings) and the other is implementing your own. The first
was ruled out because it's not easy to add new converters on Mac OS
X where ICU is a part of the OS. There's another approach you can
take. You can build ICU transliterator rules and it seems to be the
cleanest way to do this. You don't need to port/implement conversion
code (from another project : e.g. Padma) but just need to 'port' the
conversion tables to ICU transliterator rules.
This transcoding will be invoked on the content of a text node
already in Unicode just like 'text-transform: capitalize' or 'text-
transform: lowercase' is. ICU transformer is for transforming a
chunk of text in Unicode to another chunk of text in Unicode.
( http://www.icu-project.org/userguide/Transform.html ) So, it
appears to be almost a perfect fit.
This sounds like it would work for any ICU-based, though it would
prevent the feature from working for ports that use something other
than ICU for unicode and text transcoding support, most notably the Qt
port. Would it simplify the code significantly to make it an ICU
transformer rather than something custom?
Regards,
Maciej
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