Support for RTL languages

[AdrianoFerrari]

just the ability to preserve right-to-left formatting once you’ve edited a note (at the moment I can control-shift to switch to right-to-left when editing, but when i save the note it jumps back to left-to-right and messes up any lists etc., same as used to be the case for Facebook statuses and the like).

[cben]

Consider auto-detecting direction from content, rather than storing it out-of-band.
Rich text editors tend to make it an out-of-band property of text, while plain-text editors tend to auto-detect:

Auto-detecting might be as simple as setting dir=auto.
I think you can't yet test auto-detected direction from CSS with :dir(rtl) / :dir(ltr), only supported by Firefox now. But you can use start/end instead of left/right everywhere to flip according to auto-detected direction.

If you want to let users force a direction, could insert RLM/LRM characters in front. The benefit is text carries its own direction, preserved when copy-pasted...

feel free to ping me for testing, I speak hebrew (unless it involves arabic shaping)

[AdrianoFerrari]

Thanks a lot for the input!
It'll come in handy when I get to working on RTL support.

[AdrianoFerrari]

dir=auto seemed to have done the trick.

Available in pre-release v2.2.2. Can you test it out, @cben ?

[cben]

Tested from master, at cf25faa

Editing is very good:

Laid out perfectly! 👏 ❤️
Each line got its own autodetected base direction 👍.

• 2 lines look weirdly autodetected but are good, they start with invisible LRM / RLM chars — the one that mentions "RLM", and the one above it that ends with the word "good".

(do you have concept of paragraphs that consist of several lines? in theory, direction per-paragraph is the Right thing per UAX9, though there are practical benefits to edit a complex mixed sentence on several lines each with its own direction... Anyway I see each line renders on a new line so I guess it's a moot distinction.)

• minor annoyance, that seems to be specific to RTL lines (or RTL cards?):
  go to logical start of line (Home), press Enter to insert a blank line above, try pressing Up to go into that blank line — cursor doesn't move up. Can be moved by mouse click though.

Display has a problem:

You set dir=auto on whole card, so what looked during editing like it's going to be indenpendently-directioned lines became all one direction (RTL because first strongly directioned char in card is RTL).

Would be better to set dir=auto on each block element coming from markdown. Each <p>, each <li> etc...
(In case of doubt, it won't harm much to set it on inline elements too. In fact, it'd be semantically better in some complex cases! however in those cases it'll diverge from order in editing, which is probably suboptimal.)

attaching my test doc:
bidi-test.gko.zip

[cben]

To be sure, it's a big strict improvement, no problem to release as-is and iterate later.
Thanks again for working on this :)

[AdrianoFerrari]

Thank you so much for the detailed tests!

Will see what I can do to fix display.

[AdrianoFerrari]

I wasn't able to (easily) set the dir=auto attribute on all child elements, since that would entail changing the markdown rendering engine. But, I found that setting unicode-bidi: plaintext seems to work:

The only issue here, is that lists aren't bidirectional, but I think that makes sense.

In any case, I'll be releasing 2.2.2 soon, with these changes. If you have any more input on improving RLT, please let me know (this issue, or new one, as you see fit).