IRC log of webfonts on 2014-09-03

Timestamps are in UTC.

13:58:30 [RRSAgent]

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logging to http://www.w3.org/2014/09/03-webfonts-irc

13:58:32 [trackbot]

RRSAgent, make logs world

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13:58:34 [trackbot]

Zakim, this will be 3668

13:58:34 [Zakim]

ok, trackbot; I see IA_Fonts()10:00AM scheduled to start in 2 minutes

13:58:35 [trackbot]

Meeting: WebFonts Working Group Teleconference

13:58:35 [trackbot]

Date: 03 September 2014

13:58:38 [RSheeter]

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13:59:12 [Zakim]

IA_Fonts()10:00AM has now started

13:59:22 [Zakim]

+Vlad

13:59:29 [Vlad]

zakim, who is here?

13:59:29 [Zakim]

On the phone I see Vlad

13:59:31 [Zakim]

On IRC I see RSheeter, Zakim, RRSAgent, Vlad, trackbot

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13:59:32 [jfkthame]

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13:59:43 [sergeym]

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13:59:54 [Zakim]

+jfkthame

14:00:47 [Zakim]

+ +1.425.882.aaaa

14:00:54 [Zakim]

+[Google]

14:01:07 [Zakim]

+ +1.408.921.aabb

14:06:19 [Vlad]

scribenick: Vlad

14:07:06 [Vlad]

Topic: WOFF2 spec clarification for conformance

14:07:42 [Vlad]

jfkthame: presenting his comments from Aug. 14 (see reference [2] in telcon agenda)

14:07:53 [ChrisL]

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14:08:43 [Zakim]

+ChrisL

14:12:04 [ChrisL]

is there a benefit to preserving original table order? are there font consumers that rely on this?

14:15:30 [Vlad]

jfkthame: table order preservation - does it matter in WOFF2? In WOFF1 the table preservation was part of the effort to produce a binary compatible output file, WOFF2 output is not going to be binary compatible

14:17:53 [ChrisLilley]

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+ChrisL.a

14:22:37 [Vlad]

sergeym: table order should be compliant with the OpenType spec, which recommends certain table order to improve font rendering performance.

14:23:17 [Vlad]

Vlad: There is no guarantee that the input font file has the correct table order so mandating to preserve that isn't sensible.

14:24:00 [Vlad]

sergeym: maybe we should require a decoder to put tables in the order that is recommended by the OT spec, regardless of what order it was in the original input file.

14:27:22 [jfkthame]

see http://www.microsoft.com/typography/otspec/recom.htm

14:27:51 [jfkthame]

look for "optimized table ordering"

14:28:09 [Vlad]

Vlad: These changes don;t seem to have an effect on the wire format of WOFF2, this should be okay as far as existing implementations are concerned

14:30:05 [Vlad]

Resolution for table order - decoders to produce the output font file that satisfy two conditions:

14:30:29 [Vlad]

1) table directory to be sorted by tag in alphabetic order:

14:30:52 [Vlad]

1) font tables to be placed in the order recommended by the OepNType spec.

14:31:20 [Vlad]

s/1)/2)

14:33:36 [Vlad]

jfkthame: table directory entry needs to be edited to tie the loose ends.

14:33:52 [Vlad]

action Vlad - edit the spec to reflect the recommended changes

14:33:53 [trackbot]

Created ACTION-134 - - edit the spec to reflect the recommended changes [on Vladimir Levantovsky - due 2014-09-10].

14:35:15 [Vlad]

ChrisL: presenting his comments (see [3])

14:37:13 [Vlad]

ChrisL - font tables are compressed in a single stream, need to make it explicit and also clarify that a single stream is for font tables only, metadata and private data blocks are completely separate.

14:40:13 [Vlad]

Topic: 255Uint16 data type

14:41:30 [Vlad]

ChrisL: current definition allow scertain values to be encoded in more than one way, we either need to change the data type definition to prevent this from happening or add a normative statement that can be tested

14:42:32 [Vlad]

action RSheeter check the current reference iomplementation to see what is currently implemented

14:42:32 [trackbot]

Created ACTION-135 - Check the current reference iomplementation to see what is currently implemented [on Roderick Sheeter - due 2014-09-10].

14:43:10 [ChrisLilley]

action-135?

14:43:10 [trackbot]

action-135 -- Roderick Sheeter to Check the current reference iomplementation to see what is currently implemented -- due 2014-09-10 -- OPEN

14:43:10 [trackbot]

http://www.w3.org/Fonts/WG/track/actions/135

14:43:29 [Vlad]

s/iomplementation/implementation

14:45:07 [Vlad]

ChrisL: UintBase128 data type must take up to 5 bytes, this can be tested.

14:46:06 [Vlad]

jfkthame: there may be multipel ways to encode the same value using UintBase128, should we prevent this from happening?

14:46:22 [RSheeter]

second the motion to forbid unlimited streams of 0 bytes :D

14:46:38 [Vlad]

- E.g., We can disallow leading zeros.

14:47:52 [ChrisLilley]

isn't that just a constraint on the allowed values of the 5th byte

14:48:20 [Vlad]

- there is a possible condition for overflow where the encoded value in UintBase128 is larger than 2^32-1 - need to specify that encoders must not allow this to happen and what the decoder should do when it encounters such a condition

14:52:27 [Vlad]

ChrisL - the spec is silent about decoder behavior regarding incorrect data encoding or overflow conditions, we need to specify that in any case when malformatted data types or overflow condition is detected the whole font should be rejected.

14:53:07 [ChrisLilley]

s/should/must

14:53:42 [Vlad]

action Vlad - edit the WOFF2 UintBase128 description to eliminate possible multiple encoded values and specify that any error conditions must invalidate the font file

14:53:42 [trackbot]

Created ACTION-136 - - edit the woff2 uintbase128 description to eliminate possible multiple encoded values and specify that any error conditions must invalidate the font file [on Vladimir Levantovsky - due 2014-09-10].

14:55:04 [Vlad]

ChrisL: on WOFF2 header - many conditions and statements from WOFF1 spec would apply, we should add them to the WOFF2 spec.

14:58:42 [ChrisLilley]

if its just for word alignment then it can be a don't care field

15:00:27 [Vlad]

ChrisL: reserved values must be 'zero', current impelementation doesn't check that.

15:00:59 [Vlad]

sergeym if we require decoders to reject the font because of a non-zero value - we eliminate the possiblity to use it in the future.

15:02:16 [Vlad]

Vlad: we can make it a FF conformance statement but not require UA to reject the font. Current WOFF2 files would be checked for comformance, UA will be able to adopt for future changes.

15:03:57 [ChrisLilley]

+1

15:03:59 [RSheeter]

looks good to me

15:04:07 [Vlad]

s/adopt/adapt

15:04:35 [Vlad]

Resolved: add a statement for FF conformance to require reserved filed be zero.

15:06:50 [Vlad]

Action ChrisL to edit the spec and implement the changes we agreed to during this call (see minutes on Sep. 3, 2014)

15:06:50 [trackbot]

Created ACTION-137 - Edit the spec and implement the changes we agreed to during this call (see minutes on sep. 3, 2014) [on Chris Lilley - due 2014-09-10].

15:07:27 [ChrisLilley]

zakim, list attendees

15:07:27 [Zakim]

As of this point the attendees have been Vlad, jfkthame, +1.425.882.aaaa, [Google], +1.408.921.aabb, ChrisL

15:08:12 [ChrisLilley]

rrsagent, make logs public

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15:11:28 [ChrisLilley]

rrsagent, make minutes

15:11:28 [RRSAgent]

I have made the request to generate http://www.w3.org/2014/09/03-webfonts-minutes.html ChrisLilley

15:11:42 [Zakim]

- +1.425.882.aaaa

15:11:44 [Zakim]

-ChrisL.a

15:11:47 [Zakim]

-jfkthame

15:11:48 [Zakim]

- +1.408.921.aabb

15:11:49 [Zakim]

-[Google]

15:11:53 [Zakim]

-Vlad

15:11:55 [ChrisLilley]

chair: vlad

15:11:57 [ChrisLilley]

rrsagent, make minutes

15:11:57 [RRSAgent]

I have made the request to generate http://www.w3.org/2014/09/03-webfonts-minutes.html ChrisLilley

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15:16:54 [Zakim]

disconnecting the lone participant, ChrisL, in IA_Fonts()10:00AM

15:16:55 [Zakim]

IA_Fonts()10:00AM has ended

15:16:55 [Zakim]

Attendees were Vlad, jfkthame, +1.425.882.aaaa, [Google], +1.408.921.aabb, ChrisL