Intent to Implement and Ship: webVTT positionAlign and lineAlign

[k2.na...@samsung.com]

Intent to Implement and Ship: webVTT  positionAlign and lineAlign

Contact emails

k2.na...@samsung.com, srir...@samsung.com

Spec

https://w3c.github.io/webvtt/

Summary

WebVTT specification added support for new optional parameters line alignment and position alignment for text rendering.

Position alignment: alignment for the cue box in the dimension of the writing direction, describing what the position is anchored to, one of line-left, line-right, center and auto.

Line alignment: alignment for the cue box’s line to start, center or end.

Adding support based on new specification for line alignment and position alignment.

Patch: https://chromium-review.googlesource.com/c/chromium/src/+/756142

Is this feature supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?

Yes

Risks

Interoperability and Compatibility

            Risks

Edge: No signals

Safari: No signals

Firefox: shipped

Web developers: No signals

There is low risk, webvtt files which are created based on old spec with some specific cases may not work as expected as there is a modification in new WebVTT spec.

 

Tracking bug

https://bugs.chromium.org/p/chromium/issues/detail?id=633690

Requesting approval to ship?

Yes

 

Entry on the feature dashboard

Yes. https://www.chromestatus.com/feature/4905656217763840

[Rick Byers]

It looks like there are web-platform-tests at least here:

http://w3c-test.org/webvtt/api/VTTCue/positionAlign.html

http://w3c-test.org/webvtt/api/VTTCue/lineAlign.html

Can you comment on the state of the test coverage in WPT (does it cover pretty much everything in the spec / your implementation)?  It looks like Firefox passes them and with your change Chrome will as well.

I also came across this Edge bug, but no signals there.

--
You received this message because you are subscribed to the Google Groups "blink-dev" group.
To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/01eb4099-1138-4f31-937f-bbe9412c91c7%40chromium.org.

[k2.na...@samsung.com]

Yes with this implementation web-platform-tests all cases your specified will pass.

Few test cases expected results and webvtt files needs update LayoutTests/media/track/ based on new specification.

below is the patch link

https://chromium-review.googlesource.com/c/chromium/src/+/756142

With this patch position align releated test case will be passed

http://w3c-test.org/webvtt/parsing/file-parsing/tests/settings-position.html

new test cases are added to check rendering position

https://chromium-review.googlesource.com/c/chromium/src/+/756142/11/third_party/WebKit/LayoutTests/media/track/track-cue-rendering-position-align-rtl.html

[Rick Byers]

Great, thanks.   LGTM1

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/15e2dfe2-ad33-4482-bfed-88e8867035e4%40chromium.org.

[Philip Jägenstedt]

LGTM2

Note that the tests in https://wpt.fyi/webvtt/api/VTTCue test the surface-level features of the API, and not actually the rendering.

Would it be possible to move the new tests in https://chromium-review.googlesource.com/c/chromium/src/+/756142 (and any others) into web-platform-tests, so that the interoperability of the rendering is also being tested?

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAFUtAY8NDBkAs2%3DMwYjP1EQuVF6cAZnRdvWXmA8-wffu9ihUvg%40mail.gmail.com.

[Chris Harrelson]

Hi,

On Thu, Nov 23, 2017 at 3:02 AM, <k2.na...@samsung.com> wrote:

Intent to Implement and Ship: webVTT  positionAlign and lineAlign

Contact emails

k2.na...@samsung.com, srir...@samsung.com

Spec

https://w3c.github.io/webvtt/

Summary

WebVTT specification added support for new optional parameters line alignment and position alignment for text rendering.

Position alignment: alignment for the cue box in the dimension of the writing direction, describing what the position is anchored to, one of line-left, line-right, center and auto.

Line alignment: alignment for the cue box’s line to start, center or end.

Adding support based on new specification for line alignment and position alignment.

Patch: https://chromium-review.googlesource.com/c/chromium/src/+/756142

Is this feature supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?

Yes

Risks

Interoperability and Compatibility

            Risks

Edge: No signals

Safari: No signals

Firefox: shipped

Clarifying question: by shipped do you mean it's shipped exactly as implemented in https://chromium-review.googlesource.com/c/chromium/src/+/756142?

 

Web developers: No signals

There is low risk, webvtt files which are created based on old spec with some specific cases may not work as expected as there is a modification in new WebVTT spec.

I see that https://chromium-review.googlesource.com/c/chromium/src/+/756142 changes the types for various interface attributes. e.g. "line" now returns A "LineAndPositionSetting" instead of "double or AutoKeyword". This does not look backward compatible. Do you have any use counters or other data to back up the assessment of low risk of breaking existing content?

 

Tracking bug

https://bugs.chromium.org/p/chromium/issues/detail?id=633690

Requesting approval to ship?

Yes

 

Entry on the feature dashboard

Yes. https://www.chromestatus.com/feature/4905656217763840

--

You received this message because you are subscribed to the Google Groups "blink-dev" group.

To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscribe@chromium.org.

[Fredrik Söderquist]

LineAndPositionSetting is just a typedef:

typedef (double or AutoKeyword) LineAndPositionSetting;

so the type is still the same. (And this part of the change is essentially unrelated to position/lineAlign.)

/fs

 

Tracking bug

https://bugs.chromium.org/p/chromium/issues/detail?id=633690

Requesting approval to ship?

Yes

 

Entry on the feature dashboard

Yes. https://www.chromestatus.com/feature/4905656217763840

--
You received this message because you are subscribed to the Google Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscribe@chromium.org.
To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/01eb4099-1138-4f31-937f-bbe9412c91c7%40chromium.org.

--
You received this message because you are subscribed to the Google Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscribe@chromium.org.

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOMQ%2Bw-oao623QX0AS4P6rchj4-nRiZVyaUuiXFhqR5Utr79qQ%40mail.gmail.com.

[srir...@samsung.com]

On Saturday, November 25, 2017 at 2:51:51 AM UTC+5:30, Philip Jägenstedt wrote:

LGTM2

Note that the tests in https://wpt.fyi/webvtt/api/VTTCue test the surface-level features of the API, and not actually the rendering.

Would it be possible to move the new tests in https://chromium-review.googlesource.com/c/chromium/src/+/756142 (and any others) into web-platform-tests, so that the interoperability of the rendering is also being tested?

Sure, we will check if we can move it to wpt.

IIRC, mozilla is not rendering "lineAlign=end" properly.

[Chris Harrelson]

LGTM3

To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscribe@chromium.org.

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/e96bf222-f5ac-4f85-bbcd-2a507ff88ea8%40chromium.org.