Re: Maybe it's time to change CFI syntax to support CSS Selector?

Hey Xu Zheng 👋

There is actually already a standard for this. Have a look at the Web
Annotation Selectors and States document

https://www.w3.org/TR/selectors-states/#CssSelector_def

https://www.w3.org/TR/selectors-states/#serializing-iri-to-url

Let's show the Web Annotations spec the love it deserves 🙂

As EPUBCFI supports "extensions" which would let you tag these selectors on
to the CFI, making it EPUB compatible 👌

http://idpf.org/epub/linking/cfi/epub-cfi.html#sec-extensions

Cheers,
Lars

On Thu, 17 Feb 2022, 03:37 Xu Zheng (gardenia), <zxu@gardenia-corp.com>
wrote:

> Hi folks
>
> This week POC (
> https://wysebee.com/?startSelector=%23home-header%3A0%3A8&endSelector=%23home-header%3A0%3A15)
> to select a random string in web browser bring me back to one question
> again.
>
> "Can we change CFI spec a bit to support CSS Selector"?
>
>
> As a reading system programmer the most difficult part to implement CFI
> for highlight are:
> 1. need to go through all element to identify element for CFI such as
> following
>
> /6/4!/4/10/2/1
>
> 2. when we have this CFI generated for highlight then it's still difficult
> to go through DOM to locate this element when rendering highlight.
>
>
> I went through CSS selector again as well it is possible to use CSS
> selector to locate every element (for example implementation like this
> https://www.npmjs.com/package/css-selector-generator).
>
> And actually I remember when someone had brought up CFI to CSS WG and Web
> browser vendor a few years ago mostly two questions raised from them:
>
> 1. why don't use CSS selector
>
> 2. should avoid inventing new way attaching to URI such as following
>
> #epubcfi(/6/4!/4/10/2/1:3[%d0%a4-%22spa%20ce%22-99%25-aa^[bb^]^^])
>
>
> The rest of CFI I think are very useful by defining charOffset of each
> text node and the node index of the target node which are not covered by
> CSS Selector (you might want to ask - can we ask CSS Selector to support
> selecting charOffset? I am not sure since CSS Selector seems only select
> element (https://www.w3.org/TR/selectors-4/#context) ).
>
>
> So I wonder, maybe we still can find a unified way to define annotation
> but with slightly changed CFI.
>
>
> In the POC I tried format like
>
> ?startSelector=<CSS Selector>:<node index>:<charOffset>&endSelector=<CSS
> Selector>:<node index>:<charOffset>
>
> But if make it more closer to "CFI" we might have something like this? So
> even if web browser might not support it natively but as long as epub could
> support then we can have something unified that end user could share
> highlight in the same book but different reading app.
>
> ?epubcfi=<CSS Selector>:<node index>:<charOffset>,<CSS Selector>:<node
> index>:<charOffset>
>
>
> And this format can satisfy "path-relative-scheme-less-URL string
> <https://url.spec.whatwg.org/#path-relative-scheme-less-url-string>"
>
>
> Cheers,
>
> --
> Zheng Xu
>
> Chief Executive Officer
> Gardenia Corphttps://gardenia-corp.com/
>
>