[MPEG-OTSPEC] Draft AHG report for your review

[Vladimir Levantovsky]

Folks,

 

I have not received any responses / comments on the draft AHG report - it
will be presented as is.

 

Also, for the next week's breakout session on Font Format work - so far I've
got the following topics we need to cover to finalize the text of the
amendment:

-          In 5.7.11.1.2.1 Color Lines: when it comes to color
interpolation, currently the spec says that color values along the color
line are linearly interpolated - is this enough?

-          In 5.7.11.1.2.2 Linear Gradients: the description of the gradient
and rotation vectors, and effects the rotation vector has on the final
results are underspecified. Issues that need additional clarifications
include 
a) rotation effect on color interpolation results if the angular distance
between gradient orientation vector and rotation vector are more than 90
degrees in either direction (CW or CCW), and
b) what effect , if any, the magnitude of the rotation vector has.
(Currently, the spec is silent about it.)

-          In 5.7.11.1.2.3 Radial Gradients: what is the expected behavior
in case where both circles overlap with r > 0?

-          In 5.7.11.1.2.3 Radial Gradients: specify the expected behavior
in case where a transform flattens both circles and their centers to a line.

-          In 5.7.11.4 COLR table and OFF font variations - discuss and
incorporate the proposed changes
<https://github.com/googlefonts/colr-gradients-spec/commit/9cfbcaefc88f487b5
47431b62dfab22ee743d9b8?short_path=f8c59e8#diff-f8c59e8d70f0a695574ea35269cf
5f70c46db8cc40daa2d5e128e8c79be10528>  in the last two paragraphs.

 

If anything is missing from this list, please let me know.

 

Thank you,

Vladimir

 

From: Vladimir Levantovsky [mailto:vladimir.levantovsky at gmail.com] 
Sent: Wednesday, January 6, 2021 7:47 PM
To: 'MPEG OT Spec list' <mpeg-otspec at lists.aau.at>
Subject: Draft AHG report for your review
Importance: High

 

Dear all,

 

Please see attached the draft of the AHG report that I will present at the
upcoming MPEG Systems (SC29/WG3) meeting next week (Jan. 11 - 15). Your
comments are appreciated.

 

We do have a number of open issues that need to be resolved in order to
finalize COLR v1 specification - it would be best if these issues are
resolved by next week, and discussed as part of the Font Format break-out
group session during the WG meeting. Currently, this break-out session is
tentatively scheduled on January 13 at 21:00 UTC. We will be using one of
the available ISO Zoom rooms; however, the meeting access information will
only be available to WG members and cannot be shared publicly.

 

I would like to bring your attention to the specific part of the AHG
Recommendations section where a promotion of the current Working Draft to
the next PDAM stage is suggested (last paragraph, also highlighted). The
final outcome related to document promotion will likely be determined based
on the results of the WG discussions. Our possible options are to either
keep the document as the Working Draft and finalize all remaining issues
before the next  WG meeting in early April, or to recommend promoting the
document to the next PDAM stage, and address the remaining _minor_ issues as
part of the ballot comments. I'd like to remind you that in order to be able
to process the ballot in time for the next meeting, it will likely be
published as two-months ballot, and the time period for submission of
comments will be very short (most National Bodies require comments to be
submitted at least three weeks prior to ballot closing date).

 

Please respond to this email with any proposed changes and corrections to
the AHG report by the end of day Friday, Jan. 8th - No comments will be
interpreted as approval!

 

Thank you,

Vladimir

 

 

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