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RE: WebVMT Status Update

From: Little, Chris <chris.little@metoffice.gov.uk>
Date: Wed, 20 May 2020 15:58:31 +0000
To: Rob Smith <rob.smith@awayteam.co.uk>
CC: "public-sdwig@w3.org" <public-sdwig@w3.org>, Gobe Hobona <ghobona@ogc.org>
Message-ID: <CWXP265MB00532B2A5FA0095810898583A7B60@CWXP265MB0053.GBRP265.PROD.OUTLOOK.COM>
Hi Rob,

Glad you found the CSS working draft. I think Amelia, as chair, editor and invited expert would be your best bet, even if she passes you on to someone else, like Tab Atkins/Tavmjong Bah (Inkscape) or Cameron McCormack (Mozilla) , both active members of the SVG WG.

There was always a trade-off between ‘soft coding’ giving flexibility and ‘hard coding’ giving performance. Graphics now is all about contexts, inheritance and side-effects, so I have no idea which option is best! I personally have a preference for flexibility and fill-color: you do not want anything else that happens to be red changing colour when you change the cue map.

HTH, Chris

From: Rob Smith <rob.smith@awayteam.co.uk>
Sent: 20 May 2020 16:22
To: Little, Chris <chris.little@metoffice.gov.uk>
Cc: public-sdwig@w3.org; Gobe Hobona <ghobona@ogc.org>
Subject: Re: WebVMT Status Update


Thanks for your email. Sorry I didn’t see your reply last month as it was filtered out of my email, which I’ve hopefully now corrected.

3.i. Thanks. I’ll ask Gobe about MIME type registration at OGC. Scott has also responded.

3.ii. I’m drafting CSS support for WebVMT using a similar approach to WebVTT [1]. There’s a common use case for WebVMT shapes [2] to have separate stroke and fill properties, e.g. a red polygon with a black outline. My first draft was:

::cue-map {
  fill-color: red;
  stroke-color: black;

I followed the SVG approach of ‘stroke-color’ and ‘fill-color’ properties, but now realise that CSS only officially supports ‘color’ and would like guidance on how best to handle this in a way that's consistent with W3C design. An alternative design may be:

::cue-map {
  fill: {
    color: red;
  stroke: {
    color: black;

I’ve since discovered a CSS Fill and Stroke Working Draft [2] which makes me think that both the above options may be okay, though would welcome expert advice. Is Amelia still the best person to contact?

Rob Smith

Away Team

[1] https://w3c.github.io/webvtt/#css-extensions

[2] https://www.w3.org/TR/fill-stroke-3/

On 19 May 2020, at 17:55, Little, Chris <chris.little@metoffice.gov.uk<mailto:chris.little@metoffice.gov.uk>> wrote:


3.i) I suggest you approach Gobe Hobona about registering the MIME types first with the OGC Naming Authority as a precursor to registering with IANA. OGC has had some recent IANA experience and is fine tuning the process.

3.ii) How about contacting the Chair of the SVG WG, Amelia Bellamy-Royds amelia.bellamy.royds@gmail.com<mailto:amelia.bellamy.royds@gmail.com>?
SVG2 is meant to be backward compatible with SVG 1.2, but modularised, with some modules actually being part of CSS and other W3C standards. Unfortunately, fill and stroke are here https://drafts.fxtf.org/fill-stroke-3/ still a FPWD. And it is CSS Level 3.

What’s the problem? (I lurk on the SVG WG)


From: Rob Smith <rob.smith@awayteam.co.uk<mailto:rob.smith@awayteam.co.uk>>
Sent: 15 May 2020 15:13
To: public-sdwig@w3.org<mailto:public-sdwig@w3.org>
Subject: WebVMT Status Update

1. Progress Made
    i. Presented WebVMT to Full Motion Video to Moving Features [1] task kick-off meeting on 7th April 2020 in OGC Testbed-16 [2].
    ii. Participated in weekly progress calls for OGC Testbed-16 FMV to Moving Features [1] task as an Observer.
    iii. Continued development of Android app in preparation for publishing on Google Play store.

2. Next Steps
     i. Create mapping between WebVMT and MISB 0903 [3] VMTI metadata for OGC T16-FMV [1] task.
     ii. Publish Android app on Google Play store.
     iii. Continue community outreach and identify more activities to promote progress towards the standardisation track.

3. Help Requested
    i. Guidance on how best to register a MIME file type [4] for WebVMT through IANA.
    ii. Advice on how to handle ‘stroke' and ‘fill' properties using CSS, similar to SVG [5], or who to contact about this.

[1] https://portal.ogc.org/files/?artifact_id=91644#PartFMV

[2] https://www.opengeospatial.org/projects/initiatives/t-16

[3] https://www.gwg.nga.mil/misb/docs/standards/ST0903.5.pdf

[4] https://www.iana.org/assignments/media-types/media-types.xhtml

[5] https://developer.mozilla.org/en-US/docs/Web/SVG/Tutorial/Fills_and_Strokes

Received on Wednesday, 20 May 2020 15:58:49 UTC

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