9.1 breaks lines in middle of words in Khmer script - fix?

Question

I recently reported to the developers that 9.1 (unlike 8 or 9.0) is regularly breaking lines in the middle of words (and we have spaces between words!). Our project uses a non-Western script (Khmer). I wonder whether others working with non-Western scripts have this problem now? If so, please report the bug and help make it a priority.

Also, if you know of a hack to fix this, please share.

Incidentally, in this respect, PT 9.1 now behaves like Microsoft Word, which for years has broken lines in the middle of Khmer script words, even when words are separated by spaces. (Our language is strongly isolating, so we’re not talking about long words!) I wonder whether PT 9.1 changed how it renders text and uses technology similar to Microsoft’s? If so, I hope the developers will reconsider this choice.

Answer 1

Looks like this was already reported as PTX-20833

Harfbuzz delegates line breaking decisions. Previously complex link breaking, (needed for Khmer and 3 other languages) was determined by asking uniscribe. This is now done by asking icu, which fixed line breaking for some languages. This is likely the cause of the change.

Comments

Trying with your project and 9.1.104.59, appears to work for me:

With the option enabled:

1162×173

and:

1091×169

With the option disabled:

1095×143

I know I have a different font to you, but I couldn’t locate Khmer Barkaew font. I don’t think that would make a difference but it might be worth ruling out. (If you could easily provide me with the font, then I will test with it).

So If you agree that my screenshots show the expected behavior (and I’m not misunderstanding the problem), and the font doesn’t make a difference, then I think it’s worth checking the paratext update process worked as expected.

In windows explorer could you navigate to C:\Program Files\Paratext 9\Firefox64 and right click → properties on xul.dll. The Size: field should be “75,891,200 bytes” If it’s not then that is likely the cause of this.

If the size doesn’t match then you can fix this manually by doing the following:

download:
https://www.nuget.org/api/v2/package/Geckofx60.64.Windows/0.18.0
rename download extension to .zip

Extract out file: content/Firefox64/xul.dll

1. stop paratext.
2. rename C:\Program Files\Paratext 9\Firefox64\xul.dll to xul.dll_original
3. copy xul.dll from zip file into C:\Program Files\Paratext 9\Firefox64\
4. restart paratext

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The files in the download fixed it for me.

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Is there any chance that this could also be done for Thai script languages? I tried to replace the xul.dll following these instructions, but it didn’t make a difference, the words on the screen in Paratext for our Thai-based language still split across lines, so I guess it only applies to Khmer?

Linda119

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This fixed it for me, too. Thanks!

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Hi Linda119,

The languages that this option effects are:
Thai, Lao, Tibetan, Khmer
(Perhaps the label for this option isn’t the best. As in addition to being relevant to additional languages, having it unchecked does support complex line breaks. My understanding is that unchecked is more compliant with Unicode with respect to how line breaks are done, which may be different to how things used to work.)

All this option does is revert to Paratexts previous complex line breaking behaviour.
So if you observed an wanted line breaking change when moving from 9.0 to 9.1 then this option gives you the old behaviour.

Answer 2

That change was definitely unintentional. Paratext uses the Firefox Harfbuzz layout engine, so it’s possible there was an update to that system that broke this.

Please use Help > Give feedback so we can look closer at this problem.