[Bug 2131516] New: Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

Bug ID: 2131516
           Summary: Sinhala letters shake, wobble and momentarily
                    disappear and reappear when typing, sometimes with
                    wrong cursor positions.
           Product: Fedora
           Version: 37
            Status: NEW
         Component: ibus-m17n
          Assignee: [e-mail]
          Reporter: [e-mail]
        QA Contact: [e-mail]
                CC: [e-mail], [e-mail],
                    [e-mail], [e-mail]
  Target Milestone: ---
    Classification: Fedora

Created attachment 1915511
  --> https://bugzilla.redhat.com/attachment.cgi?id=1915511&action=edit
Issue reproduced with gedit on GNOME + Wayland.

Description of problem:

When typing Sinhala text with ibus, the characters shake and wobble, making
writing experience uncomfortable. Letters sometimes disappear for a moment and
reappear. Two cursor positions or wrong cursor positions seem to appear during
the process. The latter is somewhat similar to the issue described here
https://gitlab.gnome.org/GNOME/pango/-/issues/684

Version-Release number of selected component (if applicable):

How reproducible:
Reproducible throughout the system.

Environment : Fedora 37 beta, GNOME on Wayland.
Applications : Gedit, Firefox, LibreOffice.

Steps to Reproduce:
1. Enable Sinhala input with si-wijesekera
2. Type : isxy, NdIdfjka ,sjSfua oS wlqrq Tn fudn mksk whqrq ksrSlaIKh lrkak'
(සිංහල භාෂාවෙන් ලිවීමේ දී අකුරු ඔබ මොබ පනින අයුරු නිරීක්ෂණය කරන්න.)
3. Typing any meaningful chunk of text can actually demonstrate the issue.

Actual results:
See attachments

Expected results:
Smooth typing without shaking, wobbling and disappearing/reappearing of
characters. The issue is already there to a lesser extent on Fedora 36 too. So
I am unable to show you a video of the ideal expected result at the moment.

Additional info:

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

--- Comment #1 from Lohan G  ---
Created attachment 1915512
  --> https://bugzilla.redhat.com/attachment.cgi?id=1915512&action=edit
Two cursors?

The lines that appear on both sides of the letter, possibly a wrong cursor
position or two cursors?

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

Lohan G  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |[e-mail]
           Severity|unspecified                 |medium

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

Parag Nemade  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|[e-mail]          |[e-mail]
           Doc Type|---                         |If docs needed, set a value

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

--- Comment #2 from Lohan G  ---
Created attachment 1915848
  --> https://bugzilla.redhat.com/attachment.cgi?id=1915848&action=edit
Something close to the expected result : ibus-typing-booster + LibreOffice

Shaking/wobbling doesn't occur with ibus-typing-booster; characters don't
disappear and reappear. This is the closest to the expected outcome I could get
on Fedora 37.

However, the cursor position issue (or two simultaneous cursors) can still be
seen when typing in gedit.

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

--- Comment #3 from Mike FABIAN  ---
I believe this two cursor thing is a pango problem.

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

--- Comment #4 from Mike FABIAN  ---
Created attachment 1915902
  --> https://bugzilla.redhat.com/attachment.cgi?id=1915902&action=edit
Small test file to show the double cursor problem.

The test file contains:

ම U+0DB8 SINHALA LETTER MAYANNA
ො U+0DDC SINHALA VOWEL SIGN KOMBUVA HAA AELA-PILLA
මො

If this is displayed in gedit and the cursor it positioned after the final
character in the 3rd line, one sees a double cursor.

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

--- Comment #5 from Mike FABIAN  ---
Created attachment 1915903
  --> https://bugzilla.redhat.com/attachment.cgi?id=1915903&action=edit
Video showing the problem using the test file
sinhala-double-cursor-problem-test-text.txt in gedit

gedit sinhala-double-cursor-problem-test-text.txt

Then move the cursor to the end of the text and step backwards.

When the cursor is at the end of the text, double cursor is shown.

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

Mike FABIAN  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |caillon+fedoraproject@gmail
                   |                            |.com,
                   |                            |[e-mail]
                   |                            |ect.org,
                   |                            |[e-mail]
                   |                            |ct.org, [e-mail],
                   |                            |[e-mail],
                   |                            |[e-mail],
                   |                            |[e-mail],
                   |                            |[e-mail],
                   |                            |[e-mail]
          Component|ibus-m17n                   |pango
           Assignee|[e-mail]          |[e-mail]

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

Mike FABIAN  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |needinfo?([e-mail]
                   |                            |)

--- Comment #6 from Mike FABIAN  ---
Which versions of pango and harfbuzz do you have installed?

I currently have

mfabian@fedora:~
$ cat /etc/fedora-release 
Fedora release 37 (Thirty Seven)
mfabian@fedora:~
$ rpm -q pango harfbuzz
pango-1.50.10-1.fc37.x86_64
harfbuzz-5.2.0-1.fc37.x86_64
mfabian@fedora:~
$

and I cannot reproduce the problem with the double cursor anymore.

I can still reproduce it on Fedora 36 with these versions of pango and
harfbuzz:

$ rpm -q pango harfbuzz
pango-1.50.9-1.fc36.x86_64
pango-1.50.9-1.fc36.i686
harfbuzz-4.0.0-2.fc36.x86_64
harfbuzz-4.0.0-2.fc36.i686

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

Lohan G  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|needinfo?([e-mail] |
                   |)                           |

--- Comment #7 from Lohan G  ---
(In reply to Mike FABIAN from comment #6)
> Which versions of pango and harfbuzz do you have installed?
>
> I currently have
>
> mfabian@fedora:~
> $ cat /etc/fedora-release 
> Fedora release 37 (Thirty Seven)
> mfabian@fedora:~
> $ rpm -q pango harfbuzz
> pango-1.50.10-1.fc37.x86_64
> harfbuzz-5.2.0-1.fc37.x86_64
> mfabian@fedora:~
> $
>
> and I cannot reproduce the problem with the double cursor anymore.
>
> I can still reproduce it on Fedora 36 with these versions of pango and
> harfbuzz:
>
> $ rpm -q pango harfbuzz
> pango-1.50.9-1.fc36.x86_64
> pango-1.50.9-1.fc36.i686
> harfbuzz-4.0.0-2.fc36.x86_64
> harfbuzz-4.0.0-2.fc36.i686

1) My Fedora 37 beta system has:

[lohan@fedora ~]$ cat /etc/fedora-release
Fedora release 37 (Thirty Seven)
[lohan@fedora ~]$ rpm -q pango harfbuzz
pango-1.50.11-1.fc37.x86_64
harfbuzz-5.2.0-1.fc37.x86_64
[lohan@fedora ~]$

It continues to show two cursors in gedit (with both ibus-m17n and
ibus-typing-booster).

2) My Fedora 36 system has:

[lohan@fedora ~]$ cat /etc/fedora-release
Fedora release 36 (Thirty Six)
[lohan@fedora ~]$ rpm -q pango harfbuzz
pango-1.50.9-1.fc36.x86_64
harfbuzz-4.0.0-2.fc36.x86_64
[lohan@fedora ~]$

The double cursor issue continues in F 36 gedit. (with both ibus-m17n and
ibus-typing-booster).

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

--- Comment #8 from Peng Wu  ---
I think the double cursor issue is improved in Fedora 37 recently, except for
the following text:

"ලිවීමේ" input by ",sjSfua"
"අකුරු" input by "wlqrq"
"අයුරු" input by "whqrq"

For Fedora 36, after rebuild and install the harfbuzz 5.2.0 and harfbuzz-icu
5.2.0 package, the testing results is the same as Fedora 37.

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

Red Hat One Jira (issues.redhat.com)  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
            Link ID|                            |Red Hat Issue Tracker
                   |                            |FC-628

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

--- Comment #9 from Mike FABIAN  ---
(In reply to Peng Wu from comment #8)
> I think the double cursor issue is improved in Fedora 37 recently, except
> for the following text:
>
> "ලිවීමේ" input by ",sjSfua"

This one works for me in Fedora 36 and Fedora 37
> "අකුරු" input by "wlqrq"
> "අයුරු" input by "whqrq"

These two show the double cursor problem for me
> For Fedora 36, after rebuild and install the harfbuzz 5.2.0 and harfbuzz-icu
> 5.2.0 package, the testing results is the same as Fedora 37.

I also tried that now and for me as well the testing results on Fedora 36 are
the same as on Fedora 37 with harfbuzz 5.2.0

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

Peng Wu  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
            Link ID|                            |GNOME Gitlab
                   |                            |GNOME/pango/-/issues/710

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

--- Comment #10 from Mike FABIAN  ---
I tested Peng Wu’s merge request:
https://gitlab.gnome.org/GNOME/pango/-/merge_requests/653

This fixes the problem of the double cursor in

"අකුරු" input by "wlqrq"
"අයුරු" input by "whqrq"

I could find no obvious problems when playing with Arabic text in gedit, so I
think this will probably not introduce regressions for Arabic.

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

--- Comment #11 from Mike FABIAN  ---
I have just tested Peng Wu’s latest patch in the merge request 
https://gitlab.gnome.org/GNOME/pango/-/merge_requests/653
i.e. this one:

https://gitlab.gnome.org/GNOME/pango/-/merge_requests/653/diffs?commit_id=25...

and it also fixes the problem of the double cursor in

"අකුරු" input by "wlqrq"
"අයුරු" input by "whqrq"

and I also could not find any obvious problems when playing with Arabic text in
gedit.

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

Parag Nemade  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|37                          |rawhide

--- Comment #12 from Parag Nemade  ---
this will likely be fixed only when patch is merged in upstream. Not sure how
much time it will take in upstream. Hence moving the target to fix this bug to
rawhide.

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

--- Comment #14 from Aoife Moloney  ---
This message is a reminder that Fedora Linux 39 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 39 on
2024-11-26.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with
a
'version' of '39'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, change the 'version' 
to a later Fedora Linux version. Note that the version field may be hidden.
Click the "Show advanced fields" button if you do not see it.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora Linux 39 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora Linux, you are encouraged to change the 'version' to a later version
prior to this bug being closed.

[Bug 2131516] Sinhala letters shake, wobble and momentarily disappear and reappear when typing, sometimes with wrong cursor positions.

https://bugzilla.redhat.com/show_bug.cgi?id=2131516

Peng Wu  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|39                          |rawhide