Re: [ft-devel] Re: Bad Font

[David Somers]

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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