<div dir="ltr"><div><div>Thanks Ken.<br><br></div>I agree 'dist' is not ideal, for at least, it's not applied by non-Indic shapers currently.<br><br></div>What I was hinting at was that maybe we should register one catch-all required feature that can be used in the future for any such things. Separating vertical might be the easiest currently. In some future we will add direction hints to lookups and then it wouldn't be needed anymore. Currently there's no such catch-all required feature. For GSUB, people do things with 'ccmp' or 'loca' which are supposed to be always on in all shapers.<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Apr 26, 2018 at 5:25 AM, Ken Lunde <a href="mailto:lunde@adobe.com">lunde@adobe.com</a> [mpeg-OTspec] <span dir="ltr"><<a href="mailto:mpeg-OTspec-noreply@yahoogroups.com" target="_blank">mpeg-OTspec-noreply@yahoogroups.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p>Peter & Behdad,
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While I am potentially okay with hanging the functionality that I described off of the 'dist' GPOS feature, especially if there is resistance to register a new feature, I need to point out that a separate feature is definitely needed for vertical. A sufficient number of the target characters have corresponding glyphs that can be used in both writing modes, sometimes as multiples of the same glyph (GID), which is what necessitates a separate vertical feature. Does that mean that the description of 'dist' needs to be modified, and a corresponding vertical feature, perhaps tagged 'vdis', be registered?
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Also, 'kern' and 'vkrn' cannot be used for this purpose, because it is completely reasonable for a font to include both genuine kerning values (for more sophisticated environments) and the contextual spacing that I have described (for simpler environments).
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Regards...
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-- Ken
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> On Apr 25, 2018, at 8:08 PM, Peter Constable <<a href="mailto:petercon@microsoft.com" target="_blank">petercon@microsoft.com</a>> wrote:
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> Agreed: distinct features are needed when a behaviour needs to be independently-controllable by users, or if (generally only in script-specific cases) a particular sequence of feature application is needed to get required GSUB derivations. Otherwise, a separate feature serves no purpose other than a bookkeeping mechanism for the font developer, or a way to declare a supported capability to customers.
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> From: <a href="mailto:mpeg-OTspec@yahoogroups.com" target="_blank">mpeg-OTspec@yahoogroups.com</a> <<a href="mailto:mpeg-OTspec@yahoogroups.com" target="_blank">mpeg-OTspec@yahoogroups.com</a>> On Behalf Of Behdad Esfahbod <a href="mailto:behdad@behdad.org" target="_blank">behdad@behdad.org</a> [mpeg-OTspec]
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> Sent: Wednesday, April 25, 2018 3:02 PM
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> To: Ken Lunde <<a href="mailto:lunde@adobe.com" target="_blank">lunde@adobe.com</a>>
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> Cc: <a href="mailto:mpeg-OTspec@yahoogroups.com" target="_blank">mpeg-OTspec@yahoogroups.com</a>; <a href="mailto:opentype-list@indx.co.uk" target="_blank">opentype-list@indx.co.uk</a>
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> Subject: Re: [mpeg-OTspec] Registering new GPOS features?
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> OpenType is designed such that fonts can improve these kinds of things without needing a change to be rolled out to every engine first. We just need one required feature and all kinds of GSUB/GPOS things can be hung onto it. The tags should be reserved for features that are either need to be controlled by shaper, or by user. Everything else should be just one required feature.
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> On Wed, Apr 25, 2018 at 1:48 AM, Ken Lunde <a href="mailto:lunde@adobe.com" target="_blank">lunde@adobe.com</a> [mpeg-OTspec] <<a href="mailto:mpeg-OTspec-noreply@yahoogroups.com" target="_blank">mpeg-OTspec-noreply@<wbr>yahoogroups.com</a>> wrote:
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> Behdad,
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> While I see some parallels, the Indic nature of 'dist', along with the fact that a corresponding vertical feature is necessary, makes me think that separate features is better.
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> Also, and this is for others, I just noticed that a fair number of OpenType feature tags in the spec are surrounded by smart double quotes, while most are surrounded by single straight quotes. I counted that 16 features have this issue. See the attached screenshot to see the first three.
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> Regards...
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> -- Ken
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> On Apr 24, 2018, at 3:39 PM, Behdad Esfahbod <<a href="mailto:behdad@behdad.org" target="_blank">behdad@behdad.org</a>> wrote:
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> 'dist' feature?
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> behdad
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> <a href="http://behdad.org/" target="_blank">http://behdad.org/</a>
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</blockquote></div><br><br clear="all"><br>-- <br><div class="gmail_signature" data-smartmail="gmail_signature">behdad<br><a href="http://behdad.org/" target="_blank">http://behdad.org/</a></div>
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