[OpenType] RE: Proposal: deprecate ReqFeatureIndex

[Behdad Esfahbod]

On 08/22/2012 01:54 PM, Sairus Patel wrote:
> Message from OpenType list:
> 
> 
> Behdad,
> 
>> Lets be clear: the situation right now is that ReqFeatureIndex is not universally implemented, mostly because Adobe didn't implement it in some of their products.  
> 
> I'd like to understand what you mean.
> 
> When you say "ReqFeatureIndex is not universally implemented", do you mean that it's not universally (a) present in fonts, or (b) supported by layout engines?

I meant (b).  Please correct me if I'm wrong.  My understanding of your
proposal has been that "We (Adobe) have not been supporting it in Flash and
some other projects, and have not got much complaints, so it's not widely
used, so lets remove it."

I don't have anything against deprecating stuff in the spec.  But before all
of us can agree on what features are applied by default and at what stage, I
don't think there's any urgency to deprecate this particular feature.  (Which
is consistent with your other email, suggesting that a group get together to
document the layout model.)

behdad

> If (a), what would fonts need ReqFeatureIndex for? The example given for it in the spec (example 2 at http://www.microsoft.com/typography/otspec/chapter2.htm), substituting the proper form for Urdu numerals, clearly belongs to the 'locl' feature and so is misleading (and if nothing else, this correction to example 2, as in my proposal, should be made to the spec).
> 
> If (b), do you mean that other layout engines do not implement it because Adobe layout engines stopped supporting them a few years ago? Do you have an examples of such engines?
> 
> Sairus
> 
> 
> -----Original Message-----
> From: listmaster at indx.co.uk [mailto:listmaster at indx.co.uk] On Behalf Of Behdad Esfahbod 
> Sent: Wednesday, August 22, 2012 5:08 AM
> To: multiple.recipients.of.OpenType at inbound-smtp-1.corp.adobe.com
> Subject: Re: [OpenType] RE: Proposal: deprecate ReqFeatureIndex
> 
> Message from OpenType list:
> 
> 
> On 08/21/2012 07:10 PM, John Hudson wrote:
> 
>> I proposed <rclt> because I and other designers are producing type 
>> designs that rely for intended display on contextual substitutions, 
>> and that may be anything from less-than-beautiful to actually 
>> unreadable if these substitutions are turned off. In some respects, I 
>> think the OpenType assumptions of script required, language exception, 
>> and typographic optional layout are misleading, because the category 
>> of design required features does not fit neatly onto the structure. 
>> This is the category where we're increasingly working.
> 
> Fair enough.
> 
>> And I agree with you that the ReqFeatureIndex is just daffy.
> 
> IMO you are contradicting yourself, as ReqFeatureIndex does *exactly* what you are asking for.  Ie, a feature that can't be turned off!
> 
> Lets be clear: the situation right now is that ReqFeatureIndex is not universally implemented, mostly because Adobe didn't implement it in some of their products.  And because of that, it's unreliable, and as a result Adobe is requesting that it be deprecated.  Oh well...
> 
> Let me also respond to Sairus's statement that OT spec does not specify when to apply the required features.  I don't think it's a valid point, because the spec does NOT specify those kind of things for any feature...  All of us know, the details of how to use the data in the font have always been unwritten.
> 
> My 0.02CAD,
> behdad
> 
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