Re: [libreoffice-users] Re: Combining vertical text direction of page with ‘right-to-left’ text direction of a table

Hi Eyal,

Eyal Rozenberg schrieb am 11.04.2023 um 11:59:
> Anyway, with this being the state of affairs, I do not even know how the 
> ODF spec _expects_ Vertical LTR or RTL text to be rendered - if at all. 
> If you can point us to what it says about this, perhaps I could fully 
> answer.

Text direction of the page and text direction of the table are both 
written with attribute style:writing-mode in the file markup. That is 
specified in 20.404 style:writing-mode in part 3.
The meaning is not directly specified in ODF but by reference to §7.27.7 
of [XSL]. That is 
https://www.w3.org/TR/2001/REC-xsl-20011015/slice7.html#writing-mode

For rl-tb (RTL) XSL has: "Inline components and text within a line are 
written right-to-left. Lines and blocks are placed top-to-bottom."
For tb-rl (Asian, 'right-to-left (vertical)' in UI) XSL has: "Inline 
components and text within a line are written top-to-bottom. Lines and 
blocks are placed right-to-left."
And for use with tables it has: "Table-rows use the 
block-progression-direction as the row-stacking direction. The 
inline-progression-direction is used to determine the stacking direction 
for columns (and cell order within the row)."

If you take that literally, you would get a horizontal table on a 
vertical page, if the page is set to "right-to-left (vertical)" and the 
table to "right-to-left (RTL)".

But LibreOffice does not render it that way. Therefore my question 
whether the way LibreOffice renders it, is actually used. Or to be more 
specific: Do you use tables, were the origin of the table is 
bottom-right, the columns are stacked bottom-to-top and the rows are 
stacked from right-to-left?

Kind regards,
Regina












> Hello Regina,
>
> First, note that very few active RTL users are subscribed to the users' 
> mailing list; at least - to my knowledge. For discussions of RTL 
> considerations, it is often more useful to try:
>
> irc://libera.chat/libreoffice-rtl
> Telegram Group "LibreOffice RTL"
> Matrix room https://matrix.to/#/#libreoffice-rtl:libera.chat
>
> (these are now all bridged together.)
>
> Second (and again not answering your questions...) let let me give some 
> context info.
>
> To the best om my understanding, the "RTL Vertical" and "LTR Vertical" 
> exist to accommodate CJK scripts in which the glyphs appear in columns, 
> and RTL/LTR is about the order of the columns of glyphs. i.e. the 
> vertical axis is minor and the horizontal is major. I am not aware of 
> proper-RTL scripts in which glyphs are written from top to bottom.
>
> An exception could be those RTL scripts which have common non-connected 
> forms (Hebrew, N'Ko, Mende), where some vertical billboards can in 
> theory show one glyph after another in vertical order. This is extremely 
> rare for the case of Hebrew, and will certainly not be used for anything 
> that's multi-line. I don't know people from Western Africa, so in theory 
> they could have that. In Arabic and related scripts I am assuming - 
> based on some, but partial, knowledge - that this is considered irrelevant.
>
> It is more common however - but still rare - for RTL text to be rotated, 
> so that the glyphs progress horizontally in their own coordinate system, 
> but vertically in the page's coordinate system. This is what you get if 
> you set the Text Direction to "Right-to-Left (Vertical)" in LO Writer. I 
> actually believe that this is an inappropriate state of affairs, because 
> in CJK, the glyphs are _not_ rotated in Vertical text direction. I would 
> have filed a bug about this, but actually I just tried this today for 
> the first time, since the vertical text direction is not offered for RTL 
> unless you also enable CJK languages...
>
> Anyway, with this being the state of affairs, I do not even know how the 
> ODF spec _expects_ Vertical LTR or RTL text to be rendered - if at all. 
> If you can point us to what it says about this, perhaps I could fully 
> answer.
>
> I will say, though, that in principle there is no reason why a CJK 
> vertical-direction page of text cannot have a table with Hebrew or 
> Arabic text. For example, a public space sign in an Asian country's 
> airport might have vertical-direction progression and a small 
> translation table of terms containing RTL text.
>
> But I don't think that the RTL'ness itself is the real issue here, 
> because almost all of the problems such situations present would also 
> face us with LTR text.
>
> Eyal
>
>
> > Hi all,
> >
> > I’m on working to specify the property “style:writing-mode” for ODF. 
> > That property is called “text direction” in the UI of LibreOffice.
> >
> >
> > A page in a text document has the setting “Text direction” in section 
> > “Paper Format” on tab “Page” of the “Page Style” dialog. Possible 
> > values are
> >
> > Left-to-right (horizontal)
> > Right-to-left (horizontal)
> > Right-to-left (vertical)
> > Left-to-right (vertical)
> >
> > A table has the setting “Text direction” in section “Properties” on 
> > tab “Table” in “Table Properties” dialog. Possible values are
> >
> > Left-to-right (LTR)
> > Right-to-left (RTL)
> > Use superordinate object settings
> >
> > LibreOffice can combine a vertical text direction at the page with RTL 
> > text direction of the table.
> >
> >
> > Are such combinations actually used in documents?
> > Does LibreOffice render the texts in the way users need it?
> > What is the intended behavior of such combinations?
> >
> > Kind regards,
> > Regina


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