[webkit-reviews] review requested: [Bug 22339] Support Indian web sites with EOT by on-the-fly transcoding to Unicode : [Attachment 26367] Patch to support on-the-fly transcoding for one font

bugzilla-daemon at webkit.org bugzilla-daemon at webkit.org
Fri Jan 2 05:55:01 PST 2009

Prunthaban <prunthaban at google.com> has asked  for review:
Bug 22339: Support Indian web sites with EOT by on-the-fly transcoding to

Attachment 26367: Patch to support on-the-fly transcoding for one font

------- Additional Comments from Prunthaban <prunthaban at google.com>
This patch gives the whole framework to support transcoding on-the-fly when a
page is rendered. All transcoder related code is protected by
ENABLE(TRANSCODER) condition. The different classes used in this patch are to
facilitate transcoding. There are 2 abstract classes which needs to be
inherited to add support for new fonts/languages.
Encoder - This class is responsible for transforming the ASCII content into an
intermediate form.
Converter - This class converts the intermediate form into the target language.

This patch at present supports one type of font encoding (TSCII -
http://www.tscii.org/ A standardized Tamil font). The site I have used to test
the code is 'www.kalkiweekly.com' a weekly tamil magazine. 
At present the Singleton class Transformer stores the allowed list of sites and
fonts. The domain-font list is hardcoded now. I think this should be fine
because we do not have any plans to extend this framework to support all
dynamic fonts (which will be equal to supporting EOT). Each encoder needs one
class (which peroforms look-up and additional processing when required). The
size of the look-up table is on average not more than 200-300 entries. 
The entire logic behind this transcoding has been taken from padma.mozdev.org
an open source Javascript based transcoder. I have done some automation to
convert the tables in Padma to look-up tables in C++. So once we decide what
fonts and domains we are going to allow, it should not take much time to
develop the corresponding Converters & Encoders.

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