[mpeg-OTspec] rclt feature -- minor concern

Mansour, Kamal kamal.mansour at monotypeimaging.com
Thu Aug 9 01:20:04 CEST 2012


To put it in perspective, I would say that the 'rclt' feature is a welcome addition for the more complex styles of Arabic writing, but it would not be required for many simple styles. If it's present in a font, it should not be normally possible to turn it off. By the way, 'rclt' will also be useful to many other scripts which might require  more than one pass to refine the final rendered shapes.


From: Sairus Patel <sppatel at adobe.com<mailto:sppatel at adobe.com>>
Date: Wed, 8 August 2012 14:38
To: "mpeg-OTspec at yahoogroups.com<mailto:mpeg-OTspec at yahoogroups.com>" <mpeg-OTspec at yahoogroups.com<mailto:mpeg-OTspec at yahoogroups.com>>
Subject: [mpeg-OTspec] rclt feature -- minor concern


1. I received feedback that in the following sentence from the rclt specification:

> This feature is similar to 'calt', but with the difference that it should not be possible to turn off 'rclt' substitutions: they are considered essential to correct layout of the font.

“it should not be possible to turn off 'rclt'” is a bit too strong. There are always workflows in which the author may need to turn off even “required” features e.g. when preparing a specimen book chart, or other special-case scenarios.

I looked at the specification for ‘rlig’ and don’t see any such strong wording. So I propose the following to replace the above quoted sentence:

> This feature is similar to 'calt', but with the difference that 'rclt' substitutions are considered essential to correct layout of the font.

The recommendation that this feature “not be turned off, to avoid breaking obligatory shaping” is already in the UI suggestion of the rclt specification proposal.

2. Speaking of ‘rlig’, are the Arabic (and other) layout specs going to be updated to include ‘rclt’ as a required feature? rclt sounds like it has the same level of “requiredness” as rlig.


From: mpeg-OTspec at yahoogroups.com<mailto:mpeg-OTspec at yahoogroups.com> [mailto:mpeg-OTspec at yahoogroups.com] On Behalf Of Levantovsky, Vladimir
Sent: Monday, August 06, 2012 1:55 PM
To: Levantovsky, Vladimir; Thomas Phinney; Michelle Perham; OTspec
Subject: RE: [mpeg-OTspec] RE: New work on 3rd edition of the OFF (AHG kick-off)


I just uploaded an updated version with the description of ‘rclt’ feature added: http://groups.yahoo.com/group/mpeg-OTspec/files/20120806-w12847_14496-22_WD1_3rd_ed.zip

Please note that the editing period for the 3rd edition working draft text is open until the end of August, which means that if there are changes you want to propose and those changes have a consensus approval of the group – we can add them in the draft. After the editing period is over the changes would need to be submitted as input contributions for discussion at the next WG11 meeting so I strongly recommend to consider as much things done as possible until the end of the month.

Thank you,

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