[WIP][Text]Fix multiple issues with bidi text trimming

[Gillibald]

What does the pull request do?

What is the current behavior?

What is the updated/expected behavior with this PR?

How was the solution implemented (if it's not obvious)?

Checklist

• Added unit tests (if possible)?
• Added XML documentation to any related classes?
• Consider submitting a PR to https://github.com/AvaloniaUI/avalonia-docs with user documentation

Breaking changes

Obsoletions / Deprecations

Fixed issues

Fixes: #14068
Fixes: #17888
Fixes: #17569

[avaloniaui-bot]

You can test this PR using the following package version. 11.3.999-cibuild0054128-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[adirh3]

Thanks for the quick fix!
I have tested it, and it fixes almost all the issues in #17888 except when mixing RTL and LTR text.

It should look like this -

אחד שתיים שלוש Four חמש Six שבע Eight

But in Avalonia it aligned to left, like this -
אחד שתיים שלוש Four חמש Six שבע Eight

I think the issue is the resolved direction is LTR instead of RTL (which should be based on the first word (or in this case ShapedTextRun)

[Gillibald]

Thanks for the quick fix! I have tested it, and it fixes almost all the issues in #17888 except when mixing RTL and LTR text.

It should look like this -

אחד שתיים שלוש Four חמש Six שבע Eight

But in Avalonia it aligned to left, like this - אחד שתיים שלוש Four חמש Six שבע Eight

I think the issue is the resolved direction is LTR instead of RTL (which should be based on the first word (or in this case ShapedTextRun)

Your example is embedding RTL into LTR so the resolved direction is LTR. Set the FlowDirection to RTL and it should be ordered like your example.

[adirh3]

Thanks for the quick fix! I have tested it, and it fixes almost all the issues in #17888 except when mixing RTL and LTR text.

It should look like this -
אחד שתיים שלוש Four חמש Six שבע Eight
But in Avalonia it aligned to left, like this - אחד שתיים שלוש Four חמש Six שבע Eight
I think the issue is the resolved direction is LTR instead of RTL (which should be based on the first word (or in this case ShapedTextRun)

Your example is embedding RTL into LTR so the resolved direction is LTR. Set the FlowDirection to RTL and it should be ordered like your example.

I checked with RTL layout; it's not working unfortunately.

Also, I believe it should be resolving based on first token (e.g. word/character), that's the behavior I am seeing in almost all apps and I am typing a lot in RTL mixed with LTR text.

Edit: FYI this is happening with full RTL text, if it has inlines -

  <TextBlock TextTrimming="CharacterEllipsis">
          <Run Text="אחד"/>
          <Run Text="שתיים"/>
          <Run Text="שלוש"/>
          <Run Text="ארבע"/>
          <Run Text="חמש"/>
          <Run Text="שש"/>
          <Run Text="שבע"/>
          <Run Text="שמונה"/>
          <Run Text="תשע"/>
        </TextBlock> 

[Gillibald]

Chromium does the same thing

[adirh3]

Chromium does the same thing

Ok it's up to you flow direction detection, developers can easily implement it in their apps either way.
But still in Avalonia (with this PR), the text is still incorrectly displayed regardless of the flow direction.