Created attachment 137142 [details]
sample

Notes: 

A) When I test it, the letters do have the diacritics in the end -- it's only during the animation that they're missing them. This is in line with the bug title, just not completely clear in the description.

B) At least on my version, the diacritics are missing during the animation also for Latin script (attachment forthcoming -- note the double dots, dieresis, above 'G' and 'e') so this bug may not be an RTL-specific issue

C) However, what is RTL specific is that during the animation, the letters are ordered LTR. It's a bit of on oddity in Hewbrew where letters are not connected, I believe it's quite a mess in connected scripts like Arabic.




Version: 5.4.1.2.0+
Build ID: 1:5.4.1-1
CPU threads: 4; OS: Linux 4.13; UI render: default; VCL: gtk3; 
Locale: en-US (en_IL.UTF-8); Calc: group

Created attachment 137180 [details]
sample including latin script

(In reply to Shai Berger from comment #2)
> B) At least on my version, the diacritics are missing during the animation
> also for Latin script (attachment forthcoming -- note the double dots,
> dieresis, above 'G' and 'e') so this bug may not be an RTL-specific issue

I wouldnt really call those diacritics for latin, as when i tested characters like ë (U+EB) from U+C0 to U+2AF, they worked just fine.

> C) However, what is RTL specific is that during the animation, the letters
> are ordered LTR. It's a bit of on oddity in Hewbrew where letters are not
> connected, I believe it's quite a mess in connected scripts like Arabic.

Yes that is already reported in bug 55361.

(In reply to Yousuf Philips (jay) from comment #4)
> (In reply to Shai Berger from comment #2)
> > B) At least on my version, the diacritics are missing during the animation
> > also for Latin script (attachment forthcoming -- note the double dots,
> > dieresis, above 'G' and 'e') so this bug may not be an RTL-specific issue
> 
> I wouldnt really call those diacritics for latin, as when i tested
> characters like ë (U+EB) from U+C0 to U+2AF, they worked just fine.
> 

There are two ways to represent such letters: You can use the "combined" code point, like U+EB, or you can use the separate code points for a letter and the dieresis (U+A8). As far as I recall, combined code points exist for vowels only, so you couldn't write the G with dieresis this way.

RTL languages happen to have much more diverse use of diacritics than Latin scripts, but the document I attached proves that the problem is not actually RTL related. I believe you'll find Thai, which also uses combining characters heavily, to have the same problem although it's LTR.

Version: 6.1.3.2
Build ID: 1:6.1.3-1
CPU threads: 4; OS: Linux 4.18; UI render: default; VCL: gtk3_kde5; 
Locale: en-US (en_IL.UTF-8); Calc: group threaded

(Not sure it's quite the last version, but it's what I have -- it's the current version on Debian testing)

Still happens as described. One more thing I noted now,  which I don't see in the descriptions:

Before starting the animation, note in the Arabic text, the diacritic of the letter Meem (a slanted line under the left end of the right-side word). Now start slide show. When the animation ends, other diacritics show up, but this one does not.

https://gerrit.libreoffice.org/c/core/+/154066

Khaled Hosny committed a patch related to this issue.
It has been pushed to "master":

https://git.libreoffice.org/core/commit/5d2fa4ab6e75609c30351f0623dac63182be4c27

tdf#113290: Fix handling of grapheme clusters in slideshow animations

It will be available in 24.2.0.

The patch should be included in the daily builds available at
https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
https://wiki.documentfoundation.org/Testing_Daily_Builds

Affected users are encouraged to test the fix and report feedback.

(In reply to Shai Berger from comment #3)
> Created attachment 137180 [details]
> sample including latin script

The Latin text in this attachment is broken, though. The diacritic is inserted before the letters and this is degenerate when forming grapheme clusters. If the diacritic are inserted after the letters, they work fine (even after letters that does not have pre-composed diacritic form, like x).

Thanks for fixing the bug!

(In reply to ⁨خالد حسني⁩ from comment #15)
> (In reply to Shai Berger from comment #3)
> > Created attachment 137180 [details]
> > sample including latin script
> 
> The Latin text in this attachment is broken, though. The diacritic is
> inserted before the letters 

I'm not sure what that means, or how I could affect this as a user. I have no recollection of how exactly I created the document 5.5 years ago, but when I try to edit it now -- if I put the cursor after the combination and hit "backspace", it deletes only the dieresis; if I put the cursor before the combination and hit "delete", it removes the whole thing. If the order in memory (or on disk) is different, I would attribute the brokenness to LO version 5.4.1 which created it.

Khaled Hosny committed a patch related to this issue.
It has been pushed to "libreoffice-7-6":

https://git.libreoffice.org/core/commit/08152c9771b4f7d48f1a6b6dd1289d454d4f6514

tdf#113290: Fix handling of grapheme clusters in slideshow animations

It will be available in 7.6.0.0.beta2.

The patch should be included in the daily builds available at
https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
https://wiki.documentfoundation.org/Testing_Daily_Builds

Affected users are encouraged to test the fix and report feedback.

(In reply to Shai Berger from comment #16)
> Thanks for fixing the bug!
> 
> (In reply to ⁨خالد حسني⁩ from comment #15)
> > (In reply to Shai Berger from comment #3)
> > > Created attachment 137180 [details]
> > > sample including latin script
> > 
> > The Latin text in this attachment is broken, though. The diacritic is
> > inserted before the letters 
> 
> I'm not sure what that means, or how I could affect this as a user. I have
> no recollection of how exactly I created the document 5.5 years ago, but
> when I try to edit it now -- if I put the cursor after the combination and
> hit "backspace", it deletes only the dieresis; if I put the cursor before
> the combination and hit "delete", it removes the whole thing. If the order
> in memory (or on disk) is different, I would attribute the brokenness to LO
> version 5.4.1 which created it.

If I put the cursor after the G and hit backspace, I’m left with standalone diacritic, which indicate that the diacritic is before the letter not after it. After fixing this, the diacritics show correctly during animation.