EPUB 3 Working Group Telco — Minutes

Date: 2022-06-23

See also the Agenda and the IRC Log

Attendees

Present: Toshiaki Koike, Masakazu Kitahara, Dave Cramer, Matt Garrish, Matthew Chan, Shinya Takami (高見真也), Wendy Reid, Brady Duga, Murata Makoto

Regrets:

Guests:

Chair: Dave Cramer

Scribe(s): Matthew Chan

Content:

1. Allocating Bridgehead.

See github issue epub-specs#2327.

Dave Cramer: someone is a little worried about how we defined bridgehead in the SSV.
… i understand that using bridgehead won’t have any impact on anything, and given that it doesn’t exist in HTML, can we just deprecate it?.

Matt Garrish: from an a11y perspective, people misunderstand these semantics. e.g. if they type a heading as bridgehead then they think it doesn’t show up as a heading in AT.

Dave Cramer: are we still making changes to the SSV?.

Matt Garrish: we are publishing it as a note again.

Dave Cramer: okay, in that case, yes, let’s deprecate it.

Proposed resolution: Deprecate Bridgehead, close issue 2327. (Wendy Reid)

Dave Cramer: +1.

Brady Duga: +1.

Matt Garrish: +1.

Shinya Takami (高見真也): +1.

Wendy Reid: +1.

Toshiaki Koike: +1.

Matthew Chan: +1.

Resolution #1: Deprecate Bridgehead, close issue 2327.

2. Reference to Initial Containing Block definition should be improved.

See github issue epub-specs#2292.

Dave Cramer: we have a viewport meta tag for FXL. It has an informal definition in a CSS module, but Ivan feels like that isn’t a good enough reference.
… he suggests that we define it ourselves. But from experience, defining things related to layout is really difficult.

Wendy Reid: i’m in favor of defining it only because RS already use this tag in a very very specific way.
… we can even say that our definition is for RS only, and not to expect the same behaviour elsewhere.
… and the way we use it isn’t documented normatively anywhere else in our spec.

Dave Cramer: do people ever use anything else in this element other than dimensions? No other units?.

Brady Duga: I think somewhere someone has probably put ‘px’ after the number value.

Dave Cramer: the amount of variation out there is a concern.

Wendy Reid: I’ve almost always seen numeric values, not ems, not device-height.

Brady Duga: i’m almost certain we’ve had bugs related to this, but I don’t recall what weird thing people have tried.

Wendy Reid: I’e seen bugs where people try to make different content documents different sizes.

Brady Duga: there’s a test for device-height.

Wendy Reid: we could create a bunch of different test FXLs that try to use different units in this element. Easy enough to test.

Matt Garrish: when we define this with the Apple documentation it required pixels. It was only when we switched to referencing CSS that we began to open the door to these other sorts of values.
… not sure we did that intentionally.
… we could always define it strictly and see what feedback we get.

Dave Cramer: limit it to just ‘width’ and ‘height’.
… trying to imagine if various types of relative units make sense in there.
… do we know how RS would treat device-height and device-width?.

Wendy Reid: whatever viewport the RS happens to be in, maybe?
… i feel like there was guidance about this in our best practices documentation.
… what did it say?

Dave Cramer: no, we don’t say anything specific about that other than that it must be included, and all examples given are in pixel values.
… would be interested in making a FXL with ‘device-height’ and ‘device-width’ but run it in a desktop RS.

Brady Duga: Play parses the value and just takes the beginning number value regardless of what the unit is. Unless it is device-height or device-width. We pass those back.

Dave Cramer: propose that we define viewport meta, but only allow width and height properties as a restricted version of the CSS definition, but that we don’t place further restriction on what values may be used in ‘width’ and ‘height’.

Brady Duga: what about things that have initial scale on the viewport?

Wendy Reid: not part of our definition. Other properties on viewport meta are undefined.

Proposed resolution: Define the meta viewport property with only the width and height attributes as a restriction on the CSS definition, close issue 2292. (Wendy Reid)

Wendy Reid: +1.

Matthew Chan: +1.

Shinya Takami (高見真也): +1.

Dave Cramer: +1duga.

Matt Garrish: +1.

Toshiaki Koike: +1.

Brady Duga: +1.

Masakazu Kitahara: +1.

Murata Makoto: +1.

Resolution #2: Define the meta viewport property with only the width and height attributes as a restriction on the CSS definition, close issue 2292.

3. Unclear whether SVG dimensions should only apply in FXL.

See github issue epub-specs#2270.

Dave Cramer: in FXL stuff we say RS must use dimensions from ICB in rendering SVG documents. Do we respect SVG dimensions or at least proportions in reflow as well?
… I think no.

Brady Duga: agreed, this is for FXL section only.

Proposed resolution: Close issue 2270, don’t fix. (Wendy Reid)

Dave Cramer: +1.

Matt Garrish: +1.

Wendy Reid: +1.

Brady Duga: +1.

Shinya Takami (高見真也): +1.

Matthew Chan: +1.

Toshiaki Koike: +1.

Resolution #3: Close issue 2270, don’t fix.

Murata Makoto: +1.

Masakazu Kitahara: +1.

4. Should the specs address links in referenced SVGs?.

See github issue epub-specs#2261.

Dave Cramer: we don’t explicitly say what happens if you click a hyperlink in various different contexts, should we?
… our special case is links from inside epub to outside, and we discuss that case.
… for other contexts, that behaviour is covered by the appropriate spec.

Brady Duga: +1matt.

Proposed resolution: Close issue 2261, won’t fix. (Wendy Reid)

Brady Duga: +1.

Wendy Reid: +1.

Toshiaki Koike: +1.

Shinya Takami (高見真也): +1.

Matthew Chan: +1.

Matt Garrish: +1.

Dave Cramer: +1.

Murata Makoto: +1.

Masakazu Kitahara: +1.

Resolution #4: Close issue 2261, won’t fix.

5. AOB?.

Dave Cramer: I’ll be out next week, but back the week after.
… okay, thank you everyone, see you all later.

6. Resolutions