[External] : Re: Question: bidi navigation

Nir Lisker nlisker at gmail.com
Tue Oct 17 10:43:25 UTC 2023


I have just tested on Win10: Notepad, Wordpad, MSWord 2021, Discord
desktop, WhatsApp desktop, Opera, Eclipse, Gimp 2, Audacity 2.1.3, and MS
VisualStudio 2022 all use logical. Edge uses logical in text areas and text
fields, but visual in the address bar (seems like a bug, but you can't have
spaces in web addresses anyway). I don't remember ever using a visual
navigation application, maybe it was very long ago. If there ever was a
decision there, it was made long ago, at least on Windows.

It's very important to show the cursor direction because it resolves
ambiguities. It's available in most applications.

My Windows UI is in standard English LTR. I just have an RTL language
installed.

Logical navigation is a bit easier to work with I think. The behavior at
the edge of a word that changes the direction can be surprising (see the
ambiguities above), but that can be helped with the cursor direction
indication. If we can do a custom implementation, I would go a step further
and actually resolve the position ambiguities by positioning the cursor in
accordance with the selected insertion method (RTL or LTR). This means that
the cursor will jump when switching the language, but it will make life
easier because you will easily know in which direction you're about to type.

On Mon, Oct 16, 2023 at 6:16 PM Andy Goryachev <andy.goryachev at oracle.com>
wrote:

> Nir, thank you for responding!
>
>
>
> The behavior you describe (“logical” navigation) is what can be seen in
> many, but not all applications, and that is what puzzles me.  What’s more
> interesting, the applications that use a “visual” kind of navigation, that
> is the RIGHT ARROW key always moving the cursor right regardless of the
> text, is used by javafx8 (it’s totally broken in jfx17, but it looks from
> the code that it is supposed to be the same as in javafx8), java swing, MS
> Word 2007 on Windows 10, macOS Notes app, macOS TextEdit, and Mozilla
> Thunderbird.  Also, this is the kind of navigation that some users prefer
> (based on a very, very limited sample I was able to contact).
>
>
>
> What puzzles me is that there is no apparent standard even among the
> modern applications (bundled macOS apps), although the transition from
> visual to logical navigation in MS Word might indicate that the logical
> navigation is winning.
>
>
>
> The appearance of caret is another aspect that seem to have no standard.
> In many apps the caret does not change at all, very rarely we see a flag
> indicating direction (java swing), and only javafx8 and some obsolete mac
> Carbon reference doc shows a split caret.
>
>
>
> More questions for you:
>
>    1. it looks like you are on Windows, and are you using (or have you
>    seen) a fully localized version of Windows with all the UI set to RTL mode?
>    2. Have you seen any native applications that use the visual
>    navigation model?
>
>
>
> Getting back to the problem at hand: if we were to retain the backward
> compatibility in FX, we would need to fix the “visual” navigation.  FX uses
> the split caret which some users find confusing but we probably are stuck
> with it.  If we were to assume that the “logical” navigation is a standard
> everyone is slowly converging to, then my fix for
> https://bugs.openjdk.org/browse/JDK-8296266 is the right one and we
> should declare a change in behavior.
>
>
>
> What do you think?
>
>
>
> P.S. I wonder if the logical navigation was chosen because of ease of
> implementation, or is there a deeper reason?
>
>
>
>
>
>
>
>
>
> *From: *Nir Lisker <nlisker at gmail.com>
> *Date: *Monday, October 16, 2023 at 04:52
> *To: *Andy Goryachev <andy.goryachev at oracle.com>
> *Cc: *openjfx-dev at openjdk.org <openjfx-dev at openjdk.org>
> *Subject: *[External] : Re: Question: bidi navigation
>
> This is a tricky one. All applications I have seen, and I think that's
> what people expect, is that the cursor changes direction during traversal.
>
>
>
> A key point is where the paragraph is aligned to (in Windows adjusted with
> left CTRL+SHIFT and right CTRL+SHIFT). This sets the forward and backward
> direction: if the paragraph is left-aligned, pressing the right arrow moves
> the cursor forward, and for a right aligned, the right arrow moves the
> cursor backward. Then the actual movement of the cursor is relative to the
> paragraph alignment: in RTL alignment, traversing RTL text moves the
> cursor forward, while traversing LTR moves the cursor backward.
>
>
>
> Examples
>
> In a left-aligned paragraph, pressing the right arrow will move the cursor
> (|) like this:
>
> |ab אבג cd
>
> a|b אבג cd
>
> ab| אבג cd
>
> ab |אבג cd      OR     ab אבג| cd    (there is ambiguity because the space
> character can be both RTL or LTR)
>
> ab א|בג cd
>
> ab אב|ג cd
>
> ab אבג| cd      OR     ab |אבג cd
>
> ab אבג |cd
>
> ab אבג c|d
>
> ab אבג cd|
>
>
>
> To help with navigation, the cursor has a line attached to its top showing
> which direction it's facing.
>
>
>
> Hope this helps.
>
>
>
> On Thu, Oct 12, 2023 at 3:42 AM Andy Goryachev <andy.goryachev at oracle.com>
> wrote:
>
> Hi.
>
>
>
> I have a question for people who routinely use right-to-left RTL languages
> (Arabic, Hebrew, etc.):
>
>
>
> *What is your expectation for navigating text using left/right arrow keys
> when the text contains a mixture of RTL and LTR?*
>
>
>
> It looks like there is no standard when it comes to modern applications –
> see a small sample:
>
>
> https://gist.github.com/andy-goryachev-oracle/4802f9380fb03ec2be7ac36bd98a2059
> <https://urldefense.com/v3/__https:/gist.github.com/andy-goryachev-oracle/4802f9380fb03ec2be7ac36bd98a2059__;!!ACWV5N9M2RV99hQ!P_TgGd02CrA1gNF2bW5yHBRJHFkdDqluPJmHDwIcAQ-DR_NWNd-JMkTn0x9d1m5azgCucompGMSgi7PqR7TS$>
>
>
>
> In javafx, the navigation of bidirectional (bidi) text might have been
> broken sometime after jfx8, and even jfx8 might have issues, see
>
> https://bugs.openjdk.org/browse/JDK-8296266
>
>
>
> It looks like the most modern applications use logical navigation and
> logical selection (that is, when navigating using left/right arrow keys,
> the cursor position reflects previous/next insertion indexes in the text,
> rather than visual position).  This causes the cursor to change the
> direction of movement when it crosses the bidi boundary.  Would you say
> this is the expected behavior?
>
>
>
> Thank you
>
> -andy
>
>
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