Open shiestyle opened 2 years ago
Do Apple and Amazon handle such vertically-scrollable comics as reflowable publications? If so, they are consistent.
What do Korean publishers do for vertically-scrollable comics?
@murata2makoto If they require Webtoon as reflowable, it's more critical problem :)
EPUB based Webtoon will be generated as fixed layout because comics are usually generated as fixed layout. Some major Webtoon publishers don't use EPUB but many publishers in Japan generate EPUBs and we want to generate Webtoon contents as EPUB, too.
I don't want to give a big impact for EPUB 3.3 recommendation process and I don't want to add some new normative feature for Webtoon but I wish that we will get some reasonable solution for EPUB based Webtoon contents.
It's good for us to use common custom meta data for Webtoon like “scroll-direction” but "rendition:flow" in "pre-paginated" content will indicate Webtoon in EPUB spec officially, may be another option, I think.
(Just reaction on the process like issue here.) This change, if adopted by the WG, would "only" mean an additional normative feature to the specification (either by adopting the Apple approach or by introducing a tailor-made value to rendition:flow
) and, as far as I can see, it would not affect the rest of the specification, the tests that have been already created, current implementation results, etc. It is an incremental change. Which means that it is still time to add this to the spec provided that, by the end of the year, we can:
I would think we should discuss this at the F2F and, for the discussion, we should put the process issues aside.
The rendition:flow
property has always been a bit of a mess. It was supposed to only be about overflow handling of reflowable content, but then got document transitions layered into it for scrolling, even though the transition part could be useful for fixed layouts as demonstrated here.
The original idea was that flow would only have the values paginated, scrolled, and auto. If we'd stuck with that, "ttb" could probably be specified as a value of page-progression-direction
.
@murata2makoto If they require Webtoon as reflowable, it's more critical problem :) EPUB based Webtoon will be generated as fixed layout because comics are usually generated as fixed layout.
Will Amazon and Apple buy this argument and give up their current plan?
The issue was discussed in a meeting on 2022-09-13
List of resolutions:
rendition:flow
scrolled continuous as a possible option for webtoons in EPUB, it is being incubated and requesting feedback.@iherman do you want to add this note? I probably have too many questions. (What guidance on producing webtoons should this point to, if any? Is feedback going to be to this issue or should there be a proposal issue documenting the feature more fully?)
I will try to come up with something...
see #2441
After discussion at TPAC2022, Japanese ebook industry use rendition:flow-scrolled-continuous for Webtoon style comics by EPUB format and there are no bad influence.
Recently I explained the current situation to Google Japan and recommended to use rendition:flow for Webtoons, too.
At TPAC2023, So we want to discuss again to change spec so that rendition:flow-scrolled-continuous with pre-paginated will be granted to use and will indicate Webtoon style comics as a class-3 change.
Based on our experience implementing support for Webtoons, they tend to be implemented by reading systems in a very different way from EPUB FXL:
canvas
element (vs multiple iframe
elements for EPUB FXL)iframe
elements for EPUB FXL)To fully support Webtoon, we would therefore need:
canvas
or native API)rendition:flow-scrolled-continuous
is a good fit to express how these publications should be presented either@HadrienGardeur Thanks but it's not only the approach for Webtoons but for all of Manga contents, at least in Japan. That is, many of reading systems in Japan will not render XHTML but images directly for Manga contents.
The current EPUB specs may not be the best format for Manga contents but it is used widely as a standerdized distribution format and it's a good way rahter than providing set of images with dedicated metadata for each service.
For accessibility reasons, we cannot provide direct access to bitmap images in EPUB without fallbacks.
We don't want to discuss what is the best format for Manga but how to improve EPUB spec for distribution of Webtoons contents and I'll show you that rendition:flow-scrolled-continuous
is implemented by some reading systems for this use case at TPAC 2023's session.
I am not sure what the best way to specify this content is, I have seen multiple different approaches now and they all seem to have some issues. I agree with @HadrienGardeur that rendition:flow-scrolled-continuous is not a good fit, and in fact is a misuse of this metadata property. That field does not apply to a publication as a whole, it is simply a top level default setting and is therefore not useful when specifying how a book should be rendered in its entirety. I am looking forward to further discussions at TPAC.
@bduga rendition:flow-scrolled-continuous
is specified as a metadata in OPF and I'm not sure the difference between a top level default and specifying in its entirety.
We understand it is a misuse but it has not been used for FXL and there is a potential to use without bad effect.
Let's discuss more at TPAC.
We don't want to discuss what is the best format for Manga but how to improve EPUB spec for distribution of Webtoons contents and I'll show you that rendition:flow-scrolled-continuous is implemented by some reading systems for this use case at TPAC 2023's session.
This goes beyond what's the "best format".
With a manga, while using the XHTML resources and rendering them in iframes/webviews is sub-optimal, you still get the expected user experience with single or dual page spreads.
That's not the case here with Webtoons: if the images cannot be extracted from the OPF/XHTML and rendered with the expected layout (a single "scroll"), the experience will be broken and your content won't be readable.
I wonder if it would be useful to consider web-toons format separate from specifying how the reader should optimally present fixed layout content.
<meta property="rendition:layout">pre-paginated</meta> <meta property="rendition:flow">scrolled-continuous</meta>
You could imagine this in conjunction within rendition:spread-landscape to hint to the reader that the content is best suited in landscape orientation, 2-up, with vertical scrolling between spreads.
As I read the rendition:spread property it is for declaring to the reading system how to layout the content.
So what I see us trying to find is an appropriate way to specify the per document navigation mode for a fixed layout book (scrolling, or paginated). Perhaps adding a declaration of how rendition:flow should be treated in fixed layout documents (rather than modifying how it behaves for reflowable layout) may be a path forward?
Apple Books provides a producing guideline for EPUB based vertical scrolling manga (Webtoon) which requires "rendition:flow" property in OPF file.
<meta property="rendition:flow">scrolled-continuous</meta>
But EPUB specs (ex: EPUB Reading Systems 3.3) says, "rendition:flow" property should not be used for fixed layout (pre-paginated).
Reading systems MUST ignore the rendition:flow property and its overrides when processing [pre-paginated spine items](https://www.w3.org/TR/epub-33/#def-layout-pre-paginated) [[epub-33](https://www.w3.org/TR/epub-rs-33/#bib-epub-33)].
Unfortunately, current EPUB spec, even 3.3, doesn't provide appropriate way to indicate Webtoon style and KADOKAWA and some Webtoon providers in Japan embeds custom meta data for Webtoon in our EPUB files. (ttb: Top to Bottom)
<meta name=“scroll-direction” content=“ttb”/>
Although I explained this situation, Amazon Kindle will also plan to require "rendition:flow" property for Webtoon in their guideline.
I don't want to give a big impact for EPUB 3.3 recommendation process and I don't want to add some new normative feature for Webtoon but I wish that we will get some reasonable solution for EPUB based Webtoon contents.
It's good for us to use common custom meta data for Webtoon like “scroll-direction” but "rendition:flow" in "pre-paginated" content will indicate Webtoon in EPUB spec officially, may be another option, I think.