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Re: [ft-devel] Starting work on the OpenType code
From: |
Werner LEMBERG |
Subject: |
Re: [ft-devel] Starting work on the OpenType code |
Date: |
Thu, 07 Apr 2005 13:03:24 +0200 (CEST) |
> Now I'm starting to work for AAT/TrueTypeGX validator, in
> conjunction with Masatake Yamato.
Excellent!
> Taking a glance on OT validator, its error status is only
> FT_INVALID_FORMAT (when version is undefined) or FT_INVALID_DATA
> (everything except of FT_INVALID_FORMAT).
It also uses FT_INVALID_TOO_SHORT and FT_INVALID_OFFSET (see
otvcommn.h).
> I think the data structure of OpenType tables are designed to be
> simple and these 2 error status is enough.
In ftvalid.h, more errors are defined.
> In the case of GX extensions, the tables are much complexed, and
> validation result can be more varied. [...]
Feel free to add more errors in case the stuff in fterrdef.h isn't
sufficient!
> The validation result should be defined from the viewpoint of font
> format specification? Or, the validator should consider the fragile
> font driver?
You can control this with FT_ValidationLevel. The default should
protect the font driver being quite tolerant otherwise. The highest
level, FT_VALIDATE_PARANOID should make the driver follow the font
specification as close as possible.
Werner
RE: [ft-devel] Starting work on the OpenType code, Behdad Esfahbod, 2005/04/04