Re: [ft-devel] [patch] TrueType GX/AAT validator

[George Williams]

On Tue, 2005-08-23 at 14:50, George Williams wrote:
> >     a)  14 fonts uses too-large feature number (out of defined range).
> >     b)  67 fonts uses feature number which should not be used.
> >     c) 117 fonts set wrong feature range (nSetting).
> >            this infraction is found in mort/morx.
> The 'feat' (and 'mort') documentation says:
>         Apple has defined a standard set of text features. You may
>         include one or more of these or create your own text features.
>         Font features that will be supported by your font must be part
>         of the Font Feature Registry maintained by Apple Computer, Inc.
Sorry I didn't finish...

I think the real reason feature/settings must be extensible (use numbers
not defined in Apple's Registry) is that there would be no need for the
'feat' table otherwise -- it conveys no information that is not already
in the registry.

So:
a) 14 fonts uses too-large feature number (out of defined range).
I can't find anything that says the range is a byte, but there may be
something I've missed.
b)  67 fonts uses feature number which should not be used.
I'm assuming this means features not defined in Apple's Registry. I
think this should be ok.

Or did you mean that 'morx' referred to a feature not defined in 'feat'?
That one should be illegal.
c) 117 fonts set wrong feature range (nSetting).
do you mean that more settings are defined for a feature than are
present for that feature in the 'feat' table? If so, I agree this should
be an error.

Or do you mean more settings are defined than are present in the
registry? I think that should be ok.