EPUB needs support for vertical directionality in writing
| Project: | EPUB Maintenance |
| Component: | Open Publication Structure (OPS) |
| Category: | feature request |
| Priority: | normal |
| Assigned: | GConboy |
| Status: | future consideration |
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EPUB supports left-to-right or right-to-left writing direction using the CSS2 'direction' property, but there is no way to specify that a script should be rendered top-to-bottom or bottom-to-top. The CSS3 Text Layout module has some support for vertical text. The simplest form is the 'writing-mode' shorthand property: http://dev.w3.org/csswg/css3-text-layout/#writing-mode I don't think that reading systems should be required to support vertical text, but there should be a blessed method to indicate that a document or text block would be preferentially rendered vertically if the reading system supports it. More information on the issue: http://blog.threepress.org/2009/11/22/vertical-text-in-epubcss-not-there-yet/
Excellent direction -- Likely for EPUB 3.0. We can't really add new required CSS in a maintenance version. Also adding some sort metadata indication for paging direction, could be useful.
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Comments
#1
It's a good proposal. But I don't think top-to-bottom and bottom-to-top settings are good enough for vertical text rendering.
It also needs 'page-binding-direction'.
For vertical text readers, 'Next page' means left hand page. Then Reading systems needs to change page navigation interface. And also the setting affects two page view Reading system.
This setting is also important for Manga, not comics, providers.
I know a German company who provides Manga/Comics editing system and distributes the outputs with ePub.
In their system, a cover page is located at the end of the title. And the last page is located at the head of the title.
#2
Indeed, excellent direction -- I'd think very likely for EPUB 3.0. We can't really add new required CSS for a maintenance version. But, adding such CSS3 extensions for writing-mode. Also adding some sort metadata indication for paging direction, could be useful as stated in the previous comment.
#3
Proposed resolution in "Resolution" field.
#4
Moved to future consideration.
#5
Illustration of vertical writing mode + RTL block progression:
http://threepress.org/static/labs/epub-japanese/BindingWritingMode.pdf
Sample from Voyager (www.voyager.co.jp) used with permission.
#10
I can only advise this group not to fall into the trap that other standards have done – setting up a specification so it seems to “work” with vertical text set up in a non-native reader’s idea of what Japanese needs. Just getting Japanese and Chinese right is nontrivial, and then there’s Mongolian, which upsets the apple cart entirely (since stack order is left-to-right).
There is the additional issue that horizontally-set languages can be and are typeset vertically. This fact tends to be completely overlooked.
#11
Not to worry. Very serious effort, with very knowledgeable folks, underway for EPUB3. See EGLS pages on "http://code.google.com/p/epub-revision/w/list".