Re: Updated WOFF2 spec is uploaded

Looks good to me :)

On Mon, Apr 6, 2015 at 1:16 PM, Levantovsky, Vladimir <
Vladimir.Levantovsky@monotype.com> wrote:

>  Okay, check the (new-ish) updated version and let me know if this would
> do it for you. I think it is pretty clear why DSIG has to go – I just added
> a bit more explanatory text to emphasize the uncertainty of the decoder
> actions and certainty of getting a binary mismatch between input and output
> font data.
>
>
>
> Cheers,
>
> Vlad
>
>
>
>
>
> *From:* Roderick Sheeter [mailto:rsheeter@google.com]
> *Sent:* Monday, April 06, 2015 10:57 AM
>
> *To:* Levantovsky, Vladimir
> *Cc:* w3c-webfonts-wg (public-webfonts-wg@w3.org)
> *Subject:* Re: Updated WOFF2 spec is uploaded
>
>
>
> I actually like what you just wrote: We don't know ahead of time what the
> decoder will do. We know it is very likely to change something, therefore
> remove DSIG because it is very unlikely to remain valid. I agree the spec
> already tells you this but I think it could be more direct about it.
>
>
>
> So ... maybe we could put something more like that in? (but in more
> spec-ish language :D)
>
>
>
> If the spec more directly pointed out the reasoning (improbability of DSIG
> working + inability to predict decoder behavior ahead of time), I think I
> would understand why DSIG MUST go away on first reading. Currently I think
> I'd have to read it a few times if it was my first pass through the spec.
>
>
>
> Ultimately it's fine as is; just trying to make it easier on the reader.
>
>
>
> Cheers, Rod S
>
>
>
> PS - just noticed a typo in: "between the *editros* draft used to prepare
> the First Public Working Draft and the editors draft used to prepare"
>
>
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> On Mon, Apr 6, 2015 at 7:41 AM, Levantovsky, Vladimir <
> Vladimir.Levantovsky@monotype.com> wrote:
>
> Thank Rod.
>
> Not sure I completely understand your point here – what the spec is saying
> is that there can be many things changed as a result of the WOFF2
> encoding/decoding process besides glyf/loca conversion – table order is
> among them, which can be changed by either an encoder or a decoder, with
> the obvious effect on the table directory and table offsets. Not knowing
> ahead of time what the specific changes will be on the decoder side (but
> knowing that changes are very likely to happen) we are mandating that the
> DSIG to be removed by the encoder and indicate the modifying transform by
> setting the flag in the ‘head’ table.
>
>
>
> Again, we are mandating DSIG removal _*before*_ the modifying transform
> is applied [knowing that it will be applied], and the rest of the language
> in that paragraph is the justification for it – I am not sure what else can
> be said to make it more explicit. If you have any specific language to
> suggest, please do.
>
>
>
> Thank you,
>
> Vlad
>
>
>
>
>
> *From:* Roderick Sheeter [mailto:rsheeter@google.com]
> *Sent:* Monday, April 06, 2015 10:30 AM
> *To:* Levantovsky, Vladimir
> *Cc:* w3c-webfonts-wg (public-webfonts-wg@w3.org)
> *Subject:* Re: Updated WOFF2 spec is uploaded
>
>
>
> Small comment, it (diff
> <http://email.monotype.com/wf/click?upn=-2BXp2rtJyRVICIxPLeQatHXj0p-2BD2ze7SQ44e91e7QTtjRVOdXBdstKvoTrU0xqh6vjTIkeYnVbmMHoNNWu6W-2Fqs23b3mdNbHAlx9XJOyk0A4jKP-2Fdh0DitfFyT8-2FMW4JKiAL7ceh4PtpGJhkfZDTH-2BYe57aC6kyYB3ixmm3fKXaEkTuGmB3hKpKA-2Fk6DP7pEolzUxZKvLqKhYlO14kz41OOsU2CCq398dWRpgoFLd2d4QP3CMhx59owN-2Bbm-2BUDc5A-2BDn4QNGhpeY54fub0qgBVI4SAe4YpDfgM5myUS3htOi9-2FTqdASUQpwtZH46Y1Z1OB6HiRLxbEV9h4DojjB-2FgyL1RZafT53e6nQDv-2BlrGcyBnrUTXoVwq6IvU3iq23XpuAXGWd0S1OHOIhTd7kOHwQeGavMfi-2BT89sLLvLeii2YcCdqIfDz24KzWo3q0gAkfwgugbc1ENvBEpdF7q2HWFe7tNEiiScikvEImt5f0AGih675nJ4hOl1WDEmKeVQeBQaHGwi5rEDbax5vuloNVgoNSVC7UDtL9-2BqYtT3XljVZFqfjIoAfKOmUWsrsIkjom_1G-2FjDAr7rgTstemRC6HwN-2F5kG9-2FqEkBGAZI-2BeK4lw-2BcVW6Ob5umGaaIUZzXlFgloOearTKoC7t6pr5ZAtN0r0tIchy4ExM8NGWsyRbr5-2BjpinJLY-2BTTQkQTnblQjkKql-2BsnFogcjgyVeWxfEWwigvfNbqLElf0xwxrhEPQCT-2BvgFz3kl-2FaqZEtAIBI9fbjS5V66ZK-2FiEjS2936K6UMtBpg-3D-3D>)
> says several things *may* change and therefore we MUST remove DSIG. If I
> was reading it for the first time I think I would wonder why DSIG is
> removed when none of those things had changed.
>
>
>
> Presumably it is unlikely nothing would change and it keeps things simple
> to just kill DSIG; I wonder if we should be more explicit about this?
>
>
>
> Rod S.
>
>
>
> On Thu, Apr 2, 2015 at 12:29 PM, Levantovsky, Vladimir <
> Vladimir.Levantovsky@monotype.com> wrote:
>
> Folks,
>
>
>
> I have added the details about table reordering and how changes in table
> order and their corresponding offsets affect DSIG table (to justify its
> removal for CFF fonts), and fixed a couple of typos along the way.
>
> The new version is uploaded for your reviewing pleasure!
>
> http://dev.w3.org/webfonts/WOFF2/spec/
> <http://email.monotype.com/wf/click?upn=-2BXp2rtJyRVICIxPLeQatHXj0p-2BD2ze7SQ44e91e7QTtjRVOdXBdstKvoTrU0xqh6vjTIkeYnVbmMHoNNWu6W-2Fq7mh9tp8yCy7OdbXDxYdklxsmCg88TY-2FW2x46-2F9skP4zSCoyfE9hajGMyUvDz6ysS022rE6qNDS2ffaR-2FDDBPV5Kk68xLba6-2BI8hAFeEbXOf6ugWzJ0lqo18zPMtrentqde5uprU3W4ygYCKxxzekOL3Hpf-2B3Ehb7uMIIpFHmo75b275iYKqoVAZ95s3vCj0JOR2R2G0eKLCMMdPPO6lYOkXlE7Ap8naOlXbj0wif5xRUNal3IyDRe3Mz0xv2QC1HX1E9-2BT71yVyg4S4E358-2BVKVwg5vHHyeleZqBWQHDqx3lLOfQ5RJjS3y43djWxsgw3qC9wXL7Y4jpUMcNocBz0fTwAmm-2B17ATeSXwgfbNVSnWg006kqttOEi7ZbefkxJg-3D-3D_1G-2FjDAr7rgTstemRC6HwN-2F5kG9-2FqEkBGAZI-2BeK4lw-2BcVW6Ob5umGaaIUZzXlFglo3Pwc0-2FEuwfM6PuF2MnCIVe4oxAITqkFVBOM8aKbA-2FGqPpxIpia11xKDu9ZawOvQmqXDjLlzgpw3UdKhqTrca50nDWX6lNLJ7YERcHNbUHT8jpoDss-2FGg7dbkFu2oyvJYrILM7BpjjF8AlMuxdRKNSw-3D-3D>
>
>
>
> Cheers,
>
> Vlad
>
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