bug#35435: 26.1; Gnome magnifier not following cursor when typing in emacs

bug#35435: 26.1; Gnome magnifier not following cursor when typing in emacs

[Eric Danan]

Hello,

Due to a visual impairment I constantly work with a screen magnifier 
turned on (in full screen mode), and I need it to track the cursor/caret 
to follow what I am typing.

So far I am using emacs 26.1 on cygwin on windows 10, and the windows 10 
magnifier does the job of tracking the cursor.

I am considering switching to gnome on linux and therefore installed the 
fedora (version 29) distribution to try it out. The gnome (3.30) shell 
magnifier supports cursor tracking and it works in other applications 
but not emacs (26.1).

I previously sent this message to the gnome accessibility list (that was 
a long time ago in 2015, so with earlier versions of emacs and gnome) 
and got a reply from Alex Arnaud stating:

 > I've tried to test Emacs with Accercicer (a accessibility debug tool) 
and my conclusion are Emacs doesn't connect it to AT-SPI (accessibility 
stack).

I then wrote to the emacs-devel mailing list 2 months ago and Stefan 
Monnier suggested that I open a bug.

A simple recipe to reproduce the issue is:
- Turn on gnome magnifier from Settings > Universal access,
- Launch emacs
- Start typing in the scratch buffer
As you type, the magnified area would be expected to move to follow the 
cursor, but it does not and at some point the cursor leaves the 
magnified area so you do not see what you are typing anymore.

Please let me know if any further information is needed.

Best regards,

Eric

In GNU Emacs 26.1 (build 1, x86_64-redhat-linux-gnu, GTK+ Version 3.23.2)
  of 2018-08-13 built on buildvm-13.phx2.fedoraproject.org
Windowing system distributor 'Fedora Project', version 11.0.12001000
Recent messages:
Loading 
/usr/share/emacs/site-lisp/site-start.d/desktop-entry-mode-init.el 
(source)...done
For information about GNU Emacs and the GNU system, type C-h C-a.
GNU Emacs 26.1 (build 1, x86_64-redhat-linux-gnu, GTK+ Version 3.23.2) 
of 2018-08-13
You can run the command ‘emacs-version’ with M-x em-v RET
GNU Emacs 26.1 (build 1, x86_64-redhat-linux-gnu, GTK+ Version 3.23.2) 
of 2018-08-13

Configured using:
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Configured features:
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LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
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Major mode: Lisp Interaction

Minor modes in effect:
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Load-path shadows:
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bug#35435: 26.1; Gnome magnifier not following cursor when typing in emacs

[Eli Zaretskii]

> From: Eric Danan <eric.danan@u-cergy.fr>
> Date: Fri, 26 Apr 2019 13:05:41 +0200
> 
> Due to a visual impairment I constantly work with a screen magnifier 
> turned on (in full screen mode), and I need it to track the cursor/caret 
> to follow what I am typing.
> 
> So far I am using emacs 26.1 on cygwin on windows 10, and the windows 10 
> magnifier does the job of tracking the cursor.
> 
> I am considering switching to gnome on linux and therefore installed the 
> fedora (version 29) distribution to try it out. The gnome (3.30) shell 
> magnifier supports cursor tracking and it works in other applications 
> but not emacs (26.1).
> 
> I previously sent this message to the gnome accessibility list (that was 
> a long time ago in 2015, so with earlier versions of emacs and gnome) 
> and got a reply from Alex Arnaud stating:
> 
>  > I've tried to test Emacs with Accercicer (a accessibility debug tool) 
> and my conclusion are Emacs doesn't connect it to AT-SPI (accessibility 
> stack).

The Windows port of Emacs has special code to move the system caret in
sync with the cursor.  I guess the X build should have something
similar, patches are welcome to implement that.

bug#35435: 26.1; Gnome magnifier not following cursor when typing in emacs

[Eric Danan]

Thanks for your reply. I don't have the knowledge (neither on the emacs 
code nor on X) to prepare such a patch, and I of course understand if no 
one else can do it, but I an otherwise happy to test things if that can 
help.

(Also cc'ing Alex Arnaud, which I forgot to do the first time.)

On 2019-04-26 13:14, Eli Zaretskii wrote:
>> From: Eric Danan <eric.danan@u-cergy.fr>
>> Date: Fri, 26 Apr 2019 13:05:41 +0200
>>
>> Due to a visual impairment I constantly work with a screen magnifier
>> turned on (in full screen mode), and I need it to track the cursor/caret
>> to follow what I am typing.
>>
>> So far I am using emacs 26.1 on cygwin on windows 10, and the windows 10
>> magnifier does the job of tracking the cursor.
>>
>> I am considering switching to gnome on linux and therefore installed the
>> fedora (version 29) distribution to try it out. The gnome (3.30) shell
>> magnifier supports cursor tracking and it works in other applications
>> but not emacs (26.1).
>>
>> I previously sent this message to the gnome accessibility list (that was
>> a long time ago in 2015, so with earlier versions of emacs and gnome)
>> and got a reply from Alex Arnaud stating:
>>
>>   > I've tried to test Emacs with Accercicer (a accessibility debug tool)
>> and my conclusion are Emacs doesn't connect it to AT-SPI (accessibility
>> stack).
> 
> The Windows port of Emacs has special code to move the system caret in
> sync with the cursor.  I guess the X build should have something
> similar, patches are welcome to implement that.
> 

bug#35435: 26.1; Gnome magnifier not following cursor when typing in emacs

[Eric Danan]

Hello,

For the record, it seems that cursor tracking does not work with the Mac 
OS magnifier ("zoom") either when typing in Emacs. I tested this with a 
Mac OS 10.15 virtual machine and installing Emacs from the following 
sources:

* emacsformacosx.com

* Homebrew:
** brew cask install emacs: I was not able to complete the installation 
for some reason but it is the same as emacsformacosx.com if I understand 
correctly
** brew install emacs-plus
** brew install emacs-mac

* Mac Ports
** sudo port install emacs-app
** sudo port install emacs-app-devel
** sudo port install emacs-mac-app

On the other hand, cursor tracking worked correctly in e.g. the Safari 
browser. So I guess the Mac port of Emacs does not have the "special 
code to move the system caret in sync with the cursor" that the Windows 
port has.

Eric

On 2019-05-02 09:17, Eric Danan wrote:
> Thanks for your reply. I don't have the knowledge (neither on the emacs 
> code nor on X) to prepare such a patch, and I of course understand if no 
> one else can do it, but I an otherwise happy to test things if that can 
> help.
> 
> (Also cc'ing Alex Arnaud, which I forgot to do the first time.)
> 
> On 2019-04-26 13:14, Eli Zaretskii wrote:
>>> From: Eric Danan <eric.danan@u-cergy.fr>
>>> Date: Fri, 26 Apr 2019 13:05:41 +0200
>>>
>>> Due to a visual impairment I constantly work with a screen magnifier
>>> turned on (in full screen mode), and I need it to track the cursor/caret
>>> to follow what I am typing.
>>>
>>> So far I am using emacs 26.1 on cygwin on windows 10, and the windows 10
>>> magnifier does the job of tracking the cursor.
>>>
>>> I am considering switching to gnome on linux and therefore installed the
>>> fedora (version 29) distribution to try it out. The gnome (3.30) shell
>>> magnifier supports cursor tracking and it works in other applications
>>> but not emacs (26.1).
>>>
>>> I previously sent this message to the gnome accessibility list (that was
>>> a long time ago in 2015, so with earlier versions of emacs and gnome)
>>> and got a reply from Alex Arnaud stating:
>>>
>>>   > I've tried to test Emacs with Accercicer (a accessibility debug 
>>> tool)
>>> and my conclusion are Emacs doesn't connect it to AT-SPI (accessibility
>>> stack).
>>
>> The Windows port of Emacs has special code to move the system caret in
>> sync with the cursor.  I guess the X build should have something
>> similar, patches are welcome to implement that.
>>

bug#35435: 26.1; Gnome magnifier not following cursor when typing in emacs

[Stefan Kangas]

Eric Danan <eric.danan@u-cergy.fr> writes:

> For the record, it seems that cursor tracking does not work with the Mac OS
> magnifier ("zoom") either when typing in Emacs. I tested this with a Mac OS
> 10.15 virtual machine and installing Emacs from the following sources:

My guess is that this is unrelated to the issue with the Gnome
magnifier, since macOS uses a different GUI toolkit.  I would
therefore suggest that you file a new bug report to track this issue.

Best regards,
Stefan Kangas