W3C

- DRAFT -

WebFonts Working Group Teleconference

02 Mar 2016

See also: IRC log

Attendees

Present
ChrisLilley, kuettel, sergeym, vlad, rsheeter, jonathan
Regrets
ken
Chair
vlad
Scribe
ChrisLilley

Contents


<scribe> scribe: ChrisLilley

kuettel: Rod can't get connected to the phone

Vlad: action-196?

action-196?

<trackbot> action-196 -- Vladimir Levantovsky to Review treatment of empty glyphs vs 0-contour glyphs -- due 2016-02-17 -- PENDINGREVIEW

<trackbot> http://www.w3.org/Fonts/WG/track/actions/196

Vlad: this will be an empty glyph on output

<jfkthame> (sorry to be so late)

Vlad: zero contour glyph (which is very rare) with non-zero bbox, font is considered junk. It is already a spwcial case, and has no paint. bbox should be empty in that case
... safer to reject the font. We added a test case.
... for this one and for a missing one
... pass is no output on the encoder. Other test has a zero bbox and produces an empty glyph on output

jfkthame: very much an edge case, sounds fine

(agreement)

close action-196

<trackbot> Closed action-196.

open action items

action-186?

<trackbot> action-186 -- Roderick Sheeter to Try time (decode) and size for null glyf/loca xform vs regular vs woff1 -- due 2016-03-02 -- OPEN

<trackbot> http://www.w3.org/Fonts/WG/track/actions/186

RSheeter: maybe two weeks

action-172?

<trackbot> action-172 -- Chris Lilley to Register font media types -- due 2016-04-30 -- OPEN

<trackbot> http://www.w3.org/Fonts/WG/track/actions/172

action-172 please chime in on the IETF list, new draft

https://github.com/svgeesus/ietf-justfont/issues

https://github.com/svgeesus/ietf-justfont

https://datatracker.ietf.org/doc/draft-ietf-justfont-toplevel/

kuettel: great to see this happening

jfkthame: about the fragment syntax, css fonts
... putting the fragment in the css @font-face is good

(discussion on web architecture and where fragments are defined and how client-server works when there is a fragment)

action-195?

<trackbot> action-195 -- Roderick Sheeter to Check ua test https://www.w3.org/fonts/wg/wiki/testplan20-useragent#mustrejectinvalidbase128 -- due 2016-02-17 -- OPEN

<trackbot> http://www.w3.org/Fonts/WG/track/actions/195

action-197?

<trackbot> action-197 -- Sergey Malkin to Investigate font collections; how are glyf/hmtx shared in practice -- due 2016-02-17 -- OPEN

<trackbot> http://www.w3.org/Fonts/WG/track/actions/197

sergey: I am here
... have not found any fonts like that, still investigating. Another week would be good.

Vlad: yesterday there was a suggestion for the new cts

RRSAgent: spec says not to trust those fields and we do in the current impl so we need tests for that

sergey: dedicated tests would be nice

RSheeter: spec says not to trust those fields and we do in the current impl so we need tests for that

<RSheeter> specifically WOFF2Header totalSfntSize and 'glyf's origLength

Vlad: construct a glyf table different size than original, can be smaller or larger. Will not give the exact number for target memory allocation size

RSheeter: maybe one too small, one too large

Vlad: not an error if you fail to optimise output of the decoder, or if you have a better optimisation

RSheeter: test should set the size to zero and it should still work

sergey: decoder rejects a perfectly valid font because of this issue.

Vlad: so it decodes to a valid font
... need to define the conformance case for it

sergey: spec says these are only hints, is it enough?

Vlad: need to look at the text, make it more explicit. But just in plain English

ChrisLilley: think this one is easy enough to express as a conformance requirement

RSheeter: made a unit test easily

Vlad: its total sfnt size

RSheeter: and also orig length of glyf
... Google code was trusting of that field because at the time we hoped to have exact sizes

<RSheeter> (fix on it's way)

RSheeter: so can we have a conf test where orig length is set to an unfeasibly small value and check the font decodes correctly

Vlad: yes, just checking what the spec should say

sergey: use the same wording

jfkthame: can make test where those values are zero or one. Also huge values, and require the font is not huge full of empty space

RSheeter: agreed.

sergey: why, if it is valid (but huge)?

Vlad: any data entry in the table entry can be doctored. can be done maliciously to try and do a buffer overrun
... for example if it exceeds total sfnt size

sergey: prefer the test is that the font should not be rejected. don't care about the decoded size

RSheeter: yes

Vlad: I can do that, on the test plan
... just a note on the total font size

sergey: this should be for any transformed table

Vlad: don't see a need for a cts here. Decoders will do much more complete tests to ensure they do not crash

sergey; we have valid fonts that fail because of sizes smaller than what the decoder produces

scribe: current code allocates that size. It fails.

Vlad: but that is an implementation bug

sergey: so therefore we want a test, and a stronger statement. must only be used for reference purposes. Must not reject the font.

Vlad: okay, we can do that. Change the note to a MUST NOT reject

<scribe> ACTION: vlad to add conformance clause for must not reject glyf size and original size [recorded in http://www.w3.org/2016/03/02-webfonts-minutes.html#action01]

<trackbot> Created ACTION-198 - Add conformance clause for must not reject glyf size and original size [on Vladimir Levantovsky - due 2016-03-09].

meetings

atypi and tpac coincide. atypi in warsaw, tpac in lisbon so possible to combine in one trip

Vlad: we have a choice, can attend one or both so where do we have the meeting?
... tpac gives the option of a cross-group discussion

ChrisLilley: are there groups that want to talk to us?

Vlad: plan to attend both

ChrisLilley: so do I; easier if there is a meeting at atypi

(adjourned)

kuettel: there is a google office in warsaw, if needed
... also we could takle post-woff2 plans at tpac

sergey: not sure i can meke it but will be online

jfkthame: do not usually attend

Vlad: tpac an excellent venue for a what is next discussion with a wider group, developers, anounce ahead of time to generate interest.
... perhaps one day of laundry and one of looking outside the box

(adjourned for realz this time)

Summary of Action Items

[NEW] ACTION: vlad to add conformance clause for must not reject glyf size and original size [recorded in http://www.w3.org/2016/03/02-webfonts-minutes.html#action01]
 

Summary of Resolutions

[End of minutes]

Minutes formatted by David Booth's scribe.perl version 1.144 (CVS log)
$Date: 2016/03/02 15:58:18 $

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This is scribe.perl Revision: 1.144  of Date: 2015/11/17 08:39:34  
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Found Scribe: ChrisLilley
Inferring ScribeNick: ChrisLilley
Present: ChrisLilley kuettel sergeym vlad rsheeter jonathan

WARNING: Replacing previous Regrets list. (Old list: Ken_Lunde)
Use 'Regrets+ ... ' if you meant to add people without replacing the list,
such as: <dbooth> Regrets+ ken

Regrets: ken
Found Date: 02 Mar 2016
Guessing minutes URL: http://www.w3.org/2016/03/02-webfonts-minutes.html
People with action items: vlad

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