Text trimming inconsistencies

[adirh3]

Describe the bug

There are multiple issues -

• Text trimming is inconsistent between RTL and LTR views
• Text trimming for RTL text (e.g. Hebrew) is broken - no text is showing
• Text trimming when RTL text is combined with LTR text, is showing but incorrectly (does not aligned properly to right)

To Reproduce

Add this to Control Catalog TextBlock page -

  <TextBlock Margin="0,0,10,0"
                     Text="Lorem ipsum dolor sit amet, consectetur adipiscing elit."
                     TextTrimming="CharacterEllipsis" />
          <TextBlock Margin="0,0,10,0"
                     Text="Lorem ipsum dolor sit amet, consectetur adipiscing elit."
                     TextTrimming="WordEllipsis" />
          <TextBlock Margin="0,0,10,0"
                     Text="טקסט בשפה עברית אמור להיות מוצג מימין לשמאל"
                     FontFamily="Arial"
                     TextTrimming="CharacterEllipsis" />
          <TextBlock Margin="0,0,10,0"
                     Text="טקסט בשפה עברית אמור להיות מוצג מימין לשמאל"
                     FontFamily="Arial"
                     TextTrimming="WordEllipsis" />
          <TextBlock Margin="0,0,10,0"
                     Text="אחד שתיים שלוש Four חמש Six שבע Eight"
                     FontFamily="Arial"
                     TextTrimming="CharacterEllipsis" />
          <TextBlock Margin="0,0,10,0"
                     Text="אחד שתיים שלוש Four חמש Six שבע Eight"
                     FontFamily="Arial"
                     TextTrimming="WordEllipsis" />

LTR -

Here only the English text is OK.

RTL -

Here all text is not displaying correctly, including English.

Expected behavior

Text to be displayed correctly when trimmed.
I will use GitHub to demonstrate as I assume you can't read Hebrew -

טקסט בשפה עברית אמור להיות מוצג מימין לשמאל
אחד שתיים שלוש Four חמש Six שבע Eight

Avalonia version

master

OS

No response

Additional context

I believe the issue is due to the TextBlock's FlowDirection is used when trimming and not the "resolved" flow direction.

[Gillibald]

@adirh3 please have a look at my linked PR. It does similar things as your PR but also has different and less breaking changes in other parts. I hope you don't mind.

[adirh3]

@adirh3 please have a look at my linked PR. It does similar things as your PR but also has different and less breaking changes in other parts. I hope you don't mind.

Thanks for sharing! I don't mind at all, I just wanted to understand this code a bit.
I will try out your branch with some Hebrew strings and see how it works, thanks!