Re: Open issues in the WOFF 2 draft spec

Hi Vlad,

On 27/3/14 20:34, Levantovsky, Vladimir wrote:
>
> >>      The next issue was making the transform mandatory for the glyf and
> >> loca tables. I'm fine with this. I agree with the principle of making
> >> as few things optional as possible, unless there really is some
> >> compelling reason, and don't think non-transformed glyf rises to this
> >> level.
> > Here, I'm inclined to prefer retaining the optional nature of the 
> transform.
> > I think the added cost/complexity for implementations is pretty 
> negligible,
> > and it makes it more realistic to imagine that WOFF2 may - 
> eventually, over
> > time - serve as a complete replacement for WOFF1, rather than the two
> > co-existing forever as two distinct formats.
>
> I agree that the cost of retaining 'no transform' option is negligible 
> (or even non-existent) as both the encoder and decoder implementations 
> will have to support both branches of execution - but I believe that 
> the benefit of having a 'no transform' option is also negligible. Like 
> I said in my earlier email to Raph, if we do care about squeezing as 
> much redundancy out of font data as possible, and to achieve that we 
> are contemplating an option of introducing either a specific data type 
> or a specific table directory sub-format to save 40+ bytes - the 
> savings would be more substantial if we apply 'glyf' transform to a 
> font subset of only 6 glyphs - we would eliminated 48 bytes of bbox 
> info and at least another 12 bytes of loca table. 
FWIW, a good deal of that difference might end up being eliminated by 
the Brotli compression step, so that the final difference between the 
transformed-compressed and the nontransformed-compressed may be much less.

JK

Received on Thursday, 27 March 2014 21:34:28 UTC