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Re: [ft-devel] Re: Bad Font
From: |
David Somers |
Subject: |
Re: [ft-devel] Re: Bad Font |
Date: |
Mon, 14 Mar 2005 21:57:28 +0100 |
User-agent: |
KMail/1.7.2 |
On Sunday 13 March 2005 08:15, Werner LEMBERG wrote:
> Given that David Somers is interested to support fonts with the new
> SING table -- which also don't have a `head' table -- I wonder how to
> implement that properly.
>
> What about the following: If the font uses the SFNT format, check the
> existence of the `head' table. If it is in the font, treat it as
> usual. Otherwise, if there is a `CFF ' table, extract the CFF data
> and handle it as a pure CFF. If a `SING' table is present, also use
> the data from `cmap' table.
Werner,
I think that last test should be: if SING *and* META are present....
Remember, if there is a SING table and no META table, or vice versa,
sfnt_dir_check should (must!) treat that condition as a bad font.
Also, be aware that if there is no head, then FT_Get_Sfnt_Table(face,
ft_sfnt_head) should retun null. Perhsps sfnt_dir_check should be modded to
set a flag somewhere to indicate that the face is a variant of a sfnt, so
other functions can act as appropriate. (May be setting face->os2.version to
something like FFFC, etc.... either that, or is it worth adding a new item to
the face structure to hold this condition?)
For those on this list who aren't familiar with SING, the following may be of
use:
SING Glyphlet is an extension to OpenType developed by Adobe primarily to
facilitate adding supplemental glyphs to an OpenType font (with emphasis on,
but not necessariy limited to, gaiji to a CJK font). A SING Glyphlet Font is
an OpenType font that contains the outline(s), either in a 'glyf' or 'CFF'
table, for a glyph; 'cmap', 'BASE', and 'GSUB' tables are present with the
same format and functionaliy as a regular OpenType font; there are no 'name',
'head', 'OS/2', and 'post' tables; there are two new tables, 'SING' which
contains details about the glyphlet, and 'META' which contains metadata.
Further information on the SING Glyphlet format can be found at:
http://www.adobe.com/products/indesign/sing_gaiji.html
The specifications for the SING and META tables are not available at the
moment, but I have been informed that they will be made public/available
sometime.
Adobe have a Technology Preview available as follows:
windows:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=2436
mac
http://www.adobe.com/support/downloads/detail.jsp?ftpID=2437
Greetings from Luxembourg.
--
David Somers
VoIP: FWD 622885
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