New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
What should a RS do with CSS direction property? #1614
Comments
Whatever the decision for the RSS system is, I believe it is better to add this §4.3 of the RS spec. |
CSS advises people not to use
Basically, fantasai told us never to use |
But... do we allow RS-s to turn off CSS styling? Ie, is this relevant for us? (O.k., there are older RS-s that do not do CSS at all I guess...) In any case, I believe this argument should be in the text because, at this moment, it really looks like a fairly ad-hoc constraint. Also, if I read the CSS text, it is a 'recommend' and not 'RECOMMEND'. In other words, we have made it a MUST NOT, which means RS-s have to check this, epubcheck have to test it, RS-s have to do something if it is violated, etc... Wouldn't it be possible to change the text so that:
|
There was at least one prominent reading system years ago (Stanza) that completely ignored the author stylesheet. EPUB already forbids this (and has since at least EPUB 3.0), in keeping with guidance from the CSS Working Group. EPUBCheck enforces this. What is the benefit of relaxing this restriction, going against the advice of everyone who has ever looked at the issue? Is it worth changing the spec and changing EPUBCheck? |
It has a direction attribute and unicode-bidi attribute with Aren't those equivalent? |
Oops, I missed that! Then, even if we do not change the text, we would have to refer to those, too. The current text only refers to HTML. |
Maybe not. But if we keep it as is (module the reference to the SVG things) then we have to specify what a RS has to do if and when it encounters such a value. |
Actually... is this a testable assertion? It is, but it would require checking not only the validity of the CSS files (which, I presume, EPUBcheck does) but also analyzing the CSS files to detect the usage (or not) of these terms (which, I presume, EPUBcheck does not). If my suspicion (ie, that EPUBCheck does not detect this) is correct, then a change would not affect any deployed EPUB instance. @rdeltour ? @danielweck ? |
@iherman EPUBCheck does report this as an error. See the test cases for CSS-001. If it becomes a SHOULD in the spec, downgrading the severity is an easy change. |
@rdeltour wow! I stand corrected... |
The issue was discussed in a meeting on 2021-04-09 List of resolutions:
View the transcript4. CSS DirectionSee github issue #1614. Ivan Herman: in the core spec, there is an item which says that RS must not use CSS features for direction and bidi:
Ivan Herman: in the CSS documentation this is advice based on the fact that certain browsers may not implement CSS Dave Cramer: epub says that you can't use CSS direction since epub 3.0 Matt Garrish: RS interop is critical, part of the rationale for having these requirements Brady Duga: this wasn't just fantasai's opinion, she was a representative of the CSS WG Ivan Herman: currently the RS spec doesn't say anything about this, even though we so strongly say this in core Dave Cramer: comfortable with not putting any special requirements on RS when they see this Garth Conboy: could we acknowledge this in RS spec, and specifically say that an RS is able to do whatever it feels is appropriate? Dave Cramer: yes, I would agree
|
Closing by virtue of #1627 having been merged. |
I never understood why not use CSS direction attribute.
As someone who works with RTL languages all the time, the direction seems
to me as belonging to CSS more then HTML so I am happy that W3C has decided
to give both options. I don't see any reason why a RS should behave
differently.
…--
Ori Idan CEO Helicon Books
http://www.heliconbooks.com
On Tue, Apr 6, 2021 at 11:56 AM Ivan Herman ***@***.***> wrote:
§3.3.2
<http://localhost:8001/LocalData/github/EPUB/epub-specs/epub33/core/#sec-css-req>
says:
- It MAY include any CSS properties, with the following exceptions:
- It MUST NOT use the direction property [CSS-Writing-Modes-3]. Use
the [HTML] dir attribute to set the inline base direction.
- It MUST NOT use the unicode-bidi property [CSS-Writing-Modes-3].
Use [HTML] bdo elements and dir attributes to control bidirectionality.
I am not 100% sure why this restriction is present. However, two questions
do arise:
1. What happens if I use SVG (which does not have a dir attribute,
only language, or a bdo element
2. What should be the behavior of a RS be if it finds one of these two
properties (in HTML). Is it a "*MUST* ignore" ?
—
You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub
<#1614>, or unsubscribe
<https://github.com/notifications/unsubscribe-auth/AAB43QCBH65XUNNXZ4JX4CTTHLEC7ANCNFSM42OJTCXQ>
.
|
§3.3.2 says:
I am not 100% sure why this restriction is present. However, two questions do arise:
dir
attribute, only language, or abdo
element)?The text was updated successfully, but these errors were encountered: