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* bug#10895: Quirky behaviours with Arabic text
@ 2012-02-26 23:47 sergei karhof
  2012-02-27 10:15 ` bug#10895: Screenshot #1 sergei karhof
                   ` (5 more replies)
  0 siblings, 6 replies; 15+ messages in thread
From: sergei karhof @ 2012-02-26 23:47 UTC (permalink / raw)
  To: 10895

I want to report some quirky behaviours of Emacs (devel 24.0.93 version,
running under Windows 7), when dealing with Arabic text:

1) in some fonts (e.g. courier New), the vowel marks (harakaat) are
not displayed, despite the fact that the texts contains them. However,
if the cursor passes over the relevant text, moving in the
right-to-left direction, the vowel marks become visible. Curiously, if
the cursor passes back on the text, moving in the left-to-right
direction, the vowel marks disappear.
This problem manifests itself in different ways according to the font used.
With other fonts, the problem is only partial: only part of the
diacritic signs is visible, and by passing over them with the cursor
(from right to left), they become fully visible. When passing over the
text in the opposite direction, they again become half-visible.

2) the rendering of the vowel marks is poor even when they are
displayed. For instance, vowel marks partially overlap some of the
letters, e.g. the kasrah sign overlaps the two dots of the letter yaa.

3) vowel marks are not always in synch with the main text, so that
they sometimes appear in a displaced position (e.g. on the previous
letter). This is totally unacceptable, of course.

Bottomline: there are multiple problems with the visual rendering of
the diacritics.





^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Screenshot #1
  2012-02-26 23:47 bug#10895: Quirky behaviours with Arabic text sergei karhof
@ 2012-02-27 10:15 ` sergei karhof
  2012-02-27 18:12   ` Eli Zaretskii
  2012-02-27 10:16 ` bug#10895: Screenshot #2 sergei karhof
                   ` (4 subsequent siblings)
  5 siblings, 1 reply; 15+ messages in thread
From: sergei karhof @ 2012-02-27 10:15 UTC (permalink / raw)
  To: 10895

[-- Attachment #1: Type: text/plain, Size: 24 bytes --]

See attached screenshot

[-- Attachment #2: Screenshot 1.jpg --]
[-- Type: image/jpeg, Size: 161596 bytes --]

^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Screenshot #2
  2012-02-26 23:47 bug#10895: Quirky behaviours with Arabic text sergei karhof
  2012-02-27 10:15 ` bug#10895: Screenshot #1 sergei karhof
@ 2012-02-27 10:16 ` sergei karhof
  2012-02-27 10:16 ` bug#10895: Screenshot #3 sergei karhof
                   ` (3 subsequent siblings)
  5 siblings, 0 replies; 15+ messages in thread
From: sergei karhof @ 2012-02-27 10:16 UTC (permalink / raw)
  To: 10895

[-- Attachment #1: Type: text/plain, Size: 1 bytes --]



[-- Attachment #2: Screenshot 2.jpg --]
[-- Type: image/jpeg, Size: 166197 bytes --]

^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Screenshot #3
  2012-02-26 23:47 bug#10895: Quirky behaviours with Arabic text sergei karhof
  2012-02-27 10:15 ` bug#10895: Screenshot #1 sergei karhof
  2012-02-27 10:16 ` bug#10895: Screenshot #2 sergei karhof
@ 2012-02-27 10:16 ` sergei karhof
  2012-02-27 18:17 ` bug#10895: Quirky behaviours with Arabic text Eli Zaretskii
                   ` (2 subsequent siblings)
  5 siblings, 0 replies; 15+ messages in thread
From: sergei karhof @ 2012-02-27 10:16 UTC (permalink / raw)
  To: 10895

[-- Attachment #1: Type: text/plain, Size: 1 bytes --]



[-- Attachment #2: Screenshot 3.jpg --]
[-- Type: image/jpeg, Size: 158913 bytes --]

^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Screenshot #1
  2012-02-27 10:15 ` bug#10895: Screenshot #1 sergei karhof
@ 2012-02-27 18:12   ` Eli Zaretskii
  0 siblings, 0 replies; 15+ messages in thread
From: Eli Zaretskii @ 2012-02-27 18:12 UTC (permalink / raw)
  To: sergei karhof; +Cc: 10895

> Date: Mon, 27 Feb 2012 11:15:41 +0100
> From: sergei karhof <karhof21@gmail.com>
> 
> See attached screenshot

Thanks.  Can you tell which one(s) of these 3 screenshots show correct
display?





^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Quirky behaviours with Arabic text
  2012-02-26 23:47 bug#10895: Quirky behaviours with Arabic text sergei karhof
                   ` (2 preceding siblings ...)
  2012-02-27 10:16 ` bug#10895: Screenshot #3 sergei karhof
@ 2012-02-27 18:17 ` Eli Zaretskii
  2012-02-28 16:26   ` sergei karhof
  2012-02-28 16:21 ` bug#10895: Bug: vowel marks in Arabic sergei karhof
  2020-08-17 22:34 ` bug#10895: Quirky behaviours with Arabic text Stefan Kangas
  5 siblings, 1 reply; 15+ messages in thread
From: Eli Zaretskii @ 2012-02-27 18:17 UTC (permalink / raw)
  To: Kenichi Handa, jasonr; +Cc: sergei karhof, 10895

> Date: Mon, 27 Feb 2012 00:47:36 +0100
> From: sergei karhof <karhof21@gmail.com>
> 
> I want to report some quirky behaviours of Emacs (devel 24.0.93 version,
> running under Windows 7), when dealing with Arabic text:

Thanks.

Jason and Kenichi, could you please take a look at this problem?  The
first question I'd ask is whether this is specific to Windows, or do
we have similar problems on GNU/Linux with libotf?

Sergei, could you please try invoking Emacs with the
`-xrm Emacs.fontBackend:gdi' command-line argument, and see if the
problem persists with the GDI backend?  That's assuming that GDI at
all supports Arabic shaping; I don't know enough about this to tell,
sorry.





^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Bug: vowel marks in Arabic
  2012-02-26 23:47 bug#10895: Quirky behaviours with Arabic text sergei karhof
                   ` (3 preceding siblings ...)
  2012-02-27 18:17 ` bug#10895: Quirky behaviours with Arabic text Eli Zaretskii
@ 2012-02-28 16:21 ` sergei karhof
  2020-08-17 22:34 ` bug#10895: Quirky behaviours with Arabic text Stefan Kangas
  5 siblings, 0 replies; 15+ messages in thread
From: sergei karhof @ 2012-02-28 16:21 UTC (permalink / raw)
  To: 10895

[-- Attachment #1: Type: text/plain, Size: 1608 bytes --]

Here are two more screenshots:

#4a shows a text exactly as it was loaded from the file. The vowel
marks are totally missing, except for the word 'Allah', which for some
reason displays the vowel marks. The shaddah mark above that word, in
fact, is displayed twice, which is an error! You can see the word
'Allah' which is right at the left of the cursor. Those two marks
(shaped like the number 3, but rotated 180° degrees) above the word
are the shaddah. The reason for this anomaly might be that is some
systems the word Allah is a glyph on its own, which includes the
shaddah mark; if that was the case, this part of the problem could be
solved by removing any additional shaddah mark that might have been
added to that glyph. Anyhow, this was a digression.

The main problem is that the vowel marks are not displayed at all in
the other words.

#4b shows the same text, after the cursor has passed over them. This
is the nearest it comes to displaying the vowel marks correctly. But
again, they are out of synch with the letters, so the whole
vocalization is wrong!

Yet another two problems that I just noticed:
* the vertical space allotted to each line of text is not enough. You
can see from #4b that part of the vowel marks is cut off and thus
missing. This problem might be solved by increasing the inter-line
space, but wouldn't be nice if the proper inter-line space was
calculated and set automatically by the system?
* in #4b you can see, about 1cm at the left of the cursor, that two
vowel marks are overlapping in the same space, and of course they
shouldn't.

[-- Attachment #2: #4a.jpg --]
[-- Type: image/jpeg, Size: 118543 bytes --]

[-- Attachment #3: #4b.jpg --]
[-- Type: image/jpeg, Size: 131239 bytes --]

^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Quirky behaviours with Arabic text
  2012-02-27 18:17 ` bug#10895: Quirky behaviours with Arabic text Eli Zaretskii
@ 2012-02-28 16:26   ` sergei karhof
  2012-02-29 14:54     ` Jason Rumney
  0 siblings, 1 reply; 15+ messages in thread
From: sergei karhof @ 2012-02-28 16:26 UTC (permalink / raw)
  To: Eli Zaretskii; +Cc: 10895

[-- Attachment #1: Type: text/plain, Size: 463 bytes --]

On Mon, Feb 27, 2012 at 7:17 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> Sergei, could you please try invoking Emacs with the
> `-xrm Emacs.fontBackend:gdi' command-line argument, and see if the
> problem persists with the GDI backend?  That's assuming that GDI at
> all supports Arabic shaping; I don't know enough about this to tell,
> sorry.

I have just tried this, but it totally messes up the text, as you can
see from screenshot #5 here attached.

[-- Attachment #2: #5.jpg --]
[-- Type: image/jpeg, Size: 70976 bytes --]

^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Quirky behaviours with Arabic text
  2012-02-28 16:26   ` sergei karhof
@ 2012-02-29 14:54     ` Jason Rumney
  2012-02-29 18:24       ` Eli Zaretskii
  0 siblings, 1 reply; 15+ messages in thread
From: Jason Rumney @ 2012-02-29 14:54 UTC (permalink / raw)
  To: sergei karhof; +Cc: 10895

sergei karhof <karhof21@gmail.com> writes:

> On Mon, Feb 27, 2012 at 7:17 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>
>> Sergei, could you please try invoking Emacs with the
>> `-xrm Emacs.fontBackend:gdi' command-line argument, and see if the
>> problem persists with the GDI backend?  That's assuming that GDI at
>> all supports Arabic shaping; I don't know enough about this to tell,
>> sorry.
>
> I have just tried this, but it totally messes up the text, as you can
> see from screenshot #5 here attached.

I would expect that. The GDI font backend has no support for font
shaping, which is definitely required for proper Arabic support.  What I
suspect is that Emacs is doing more in terms of supporting Arabic than
the uniscribe shaping engine expects.





^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Quirky behaviours with Arabic text
  2012-02-29 14:54     ` Jason Rumney
@ 2012-02-29 18:24       ` Eli Zaretskii
  2012-03-01 10:27         ` sergei karhof
  0 siblings, 1 reply; 15+ messages in thread
From: Eli Zaretskii @ 2012-02-29 18:24 UTC (permalink / raw)
  To: Jason Rumney; +Cc: karhof21, 10895

> From: Jason Rumney <jasonr@gnu.org>
> Cc: Eli Zaretskii <eliz@gnu.org>,  Kenichi Handa <handa@m17n.org>,  10895@debbugs.gnu.org
> Date: Wed, 29 Feb 2012 22:54:41 +0800
> 
> What I suspect is that Emacs is doing more in terms of supporting
> Arabic than the uniscribe shaping engine expects.

Like what, for example?

Does anyone know of a good treatise for Arabic shaping with Uniscribe?





^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Quirky behaviours with Arabic text
  2012-02-29 18:24       ` Eli Zaretskii
@ 2012-03-01 10:27         ` sergei karhof
  2012-03-01 14:49           ` Jason Rumney
  0 siblings, 1 reply; 15+ messages in thread
From: sergei karhof @ 2012-03-01 10:27 UTC (permalink / raw)
  To: Eli Zaretskii; +Cc: 10895

>> What I suspect is that Emacs is doing more in terms of supporting
>> Arabic than the uniscribe shaping engine expects.
>
> Like what, for example?
>
> Does anyone know of a good treatise for Arabic shaping with Uniscribe?

I don't know much about these technical matters (I am just an
end-user), but I would like to point out that as for 'shaping' the
letters (if I understand correctly what it means), it is no issue at
all, because the letters AND the vowel marks are shaped correctly. The
problem is that the vowel marks are not displayed where they should,
that they are out of synch, and that there is not enough vertical
space to contain all the vowel marks.
So I guess that the underlying rendering engine might not be the
problem; maybe it's just the way the whole thing is implemented.

sergei





^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Quirky behaviours with Arabic text
  2012-03-01 10:27         ` sergei karhof
@ 2012-03-01 14:49           ` Jason Rumney
  0 siblings, 0 replies; 15+ messages in thread
From: Jason Rumney @ 2012-03-01 14:49 UTC (permalink / raw)
  To: sergei karhof; +Cc: 10895

sergei karhof <karhof21@gmail.com> writes:

> I don't know much about these technical matters (I am just an
> end-user), but I would like to point out that as for 'shaping' the
> letters (if I understand correctly what it means), it is no issue at
> all, because the letters AND the vowel marks are shaped correctly. The
> problem is that the vowel marks are not displayed where they should,
> that they are out of synch, and that there is not enough vertical
> space to contain all the vowel marks.

Shaping in this context is about shaping whole words, not individual
letters. Positioning vowel marks correctly is part of that.





^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Quirky behaviours with Arabic text
  2012-02-26 23:47 bug#10895: Quirky behaviours with Arabic text sergei karhof
                   ` (4 preceding siblings ...)
  2012-02-28 16:21 ` bug#10895: Bug: vowel marks in Arabic sergei karhof
@ 2020-08-17 22:34 ` Stefan Kangas
  2020-08-18  4:32   ` Eli Zaretskii
  5 siblings, 1 reply; 15+ messages in thread
From: Stefan Kangas @ 2020-08-17 22:34 UTC (permalink / raw)
  To: sergei karhof; +Cc: 10895

sergei karhof <karhof21@gmail.com> writes:

> I want to report some quirky behaviours of Emacs (devel 24.0.93 version,
> running under Windows 7), when dealing with Arabic text:
>
> 1) in some fonts (e.g. courier New), the vowel marks (harakaat) are
> not displayed, despite the fact that the texts contains them. However,
> if the cursor passes over the relevant text, moving in the
> right-to-left direction, the vowel marks become visible. Curiously, if
> the cursor passes back on the text, moving in the left-to-right
> direction, the vowel marks disappear.
> This problem manifests itself in different ways according to the font used.
> With other fonts, the problem is only partial: only part of the
> diacritic signs is visible, and by passing over them with the cursor
> (from right to left), they become fully visible. When passing over the
> text in the opposite direction, they again become half-visible.
>
> 2) the rendering of the vowel marks is poor even when they are
> displayed. For instance, vowel marks partially overlap some of the
> letters, e.g. the kasrah sign overlaps the two dots of the letter yaa.
>
> 3) vowel marks are not always in synch with the main text, so that
> they sometimes appear in a displaced position (e.g. on the previous
> letter). This is totally unacceptable, of course.
>
> Bottomline: there are multiple problems with the visual rendering of
> the diacritics.

(That was 8 years ago.)

Do you still see this on a recent version of Emacs, such as the recently
released version 27.1?

Would this have been fixed by the recent addition of harfbuzz support?

Best regards,
Stefan Kangas





^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Quirky behaviours with Arabic text
  2020-08-17 22:34 ` bug#10895: Quirky behaviours with Arabic text Stefan Kangas
@ 2020-08-18  4:32   ` Eli Zaretskii
  2020-10-01 12:26     ` Stefan Kangas
  0 siblings, 1 reply; 15+ messages in thread
From: Eli Zaretskii @ 2020-08-18  4:32 UTC (permalink / raw)
  To: Stefan Kangas; +Cc: karhof21, 10895

> From: Stefan Kangas <stefan@marxist.se>
> Date: Mon, 17 Aug 2020 22:34:35 +0000
> Cc: 10895@debbugs.gnu.org
> 
> > 1) in some fonts (e.g. courier New), the vowel marks (harakaat) are
> > not displayed, despite the fact that the texts contains them. However,
> > if the cursor passes over the relevant text, moving in the
> > right-to-left direction, the vowel marks become visible. Curiously, if
> > the cursor passes back on the text, moving in the left-to-right
> > direction, the vowel marks disappear.
> > This problem manifests itself in different ways according to the font used.
> > With other fonts, the problem is only partial: only part of the
> > diacritic signs is visible, and by passing over them with the cursor
> > (from right to left), they become fully visible. When passing over the
> > text in the opposite direction, they again become half-visible.
> >
> > 2) the rendering of the vowel marks is poor even when they are
> > displayed. For instance, vowel marks partially overlap some of the
> > letters, e.g. the kasrah sign overlaps the two dots of the letter yaa.
> >
> > 3) vowel marks are not always in synch with the main text, so that
> > they sometimes appear in a displaced position (e.g. on the previous
> > letter). This is totally unacceptable, of course.
> >
> > Bottomline: there are multiple problems with the visual rendering of
> > the diacritics.
> 
> (That was 8 years ago.)
> 
> Do you still see this on a recent version of Emacs, such as the recently
> released version 27.1?
> 
> Would this have been fixed by the recent addition of harfbuzz support?

I think those problems were fixed long ago, but let's wait for the OP
to confirm, if possible.





^ permalink raw reply	[flat|nested] 15+ messages in thread

* bug#10895: Quirky behaviours with Arabic text
  2020-08-18  4:32   ` Eli Zaretskii
@ 2020-10-01 12:26     ` Stefan Kangas
  0 siblings, 0 replies; 15+ messages in thread
From: Stefan Kangas @ 2020-10-01 12:26 UTC (permalink / raw)
  To: Eli Zaretskii; +Cc: karhof21, 10895-done

Eli Zaretskii <eliz@gnu.org> writes:

>> Would this have been fixed by the recent addition of harfbuzz support?
>
> I think those problems were fixed long ago, but let's wait for the OP
> to confirm, if possible.

No further updates within 6 weeks, so I guess we will have to assume
this has been fixed.  I'm therefore closing this bug now.





^ permalink raw reply	[flat|nested] 15+ messages in thread

end of thread, other threads:[~2020-10-01 12:26 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-02-26 23:47 bug#10895: Quirky behaviours with Arabic text sergei karhof
2012-02-27 10:15 ` bug#10895: Screenshot #1 sergei karhof
2012-02-27 18:12   ` Eli Zaretskii
2012-02-27 10:16 ` bug#10895: Screenshot #2 sergei karhof
2012-02-27 10:16 ` bug#10895: Screenshot #3 sergei karhof
2012-02-27 18:17 ` bug#10895: Quirky behaviours with Arabic text Eli Zaretskii
2012-02-28 16:26   ` sergei karhof
2012-02-29 14:54     ` Jason Rumney
2012-02-29 18:24       ` Eli Zaretskii
2012-03-01 10:27         ` sergei karhof
2012-03-01 14:49           ` Jason Rumney
2012-02-28 16:21 ` bug#10895: Bug: vowel marks in Arabic sergei karhof
2020-08-17 22:34 ` bug#10895: Quirky behaviours with Arabic text Stefan Kangas
2020-08-18  4:32   ` Eli Zaretskii
2020-10-01 12:26     ` Stefan Kangas

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