[HarfBuzz] Dotted circles in harfbuzz

[Vignesh Raman]

Hi,

I found the reason for crash is the commit,

>From 5e07a3ac58f93bd5e09715d43b58c20950c2befa Mon Sep 17 00:00:00 2001
From: Jiang Jiang <jiang.jiang at nokia.com>
Date: Wed, 16 Nov 2011 15:27:28 +0100
Subject: [PATCH] Fix HarfBuzz Thai character SARA AM handling

This was added to solve a thai character overlap issue. If this commit
is removed and when the first/top level thai vocal is entered, no
crash is seen.
I'm not sure if libthai is causing some issue.

I have also added my observation to the original bug in which this
commit was discussed.,
https://bugreports.qt.io/browse/QTBUG-21206

Thanks.

On Wed, Jun 24, 2015 at 5:25 PM, John Tapsell <johnflux at gmail.com> wrote:
> I suggested to Vignesh off the mailing list to apply the following patch:
> http://pastebin.com/e3tJRYMP
>
> i.e just adding:
>
>                  glyphString[slen++] = C_DOTTED_CIRCLE;
> +               item->attributes[slen-1].dontPrint = true; // FIXME this
> will hide all dotted circle
>
> However he found that this causes a crash.  I wasn't sure of the correct fix
> for this.
>
> John
>
> On 24 June 2015 at 13:19, Vignesh Raman <rvignesh.raman at gmail.com> wrote:
>>
>> Hi All,
>>
>> I was checking a thai webpage which has a virtual keyboard,
>> https://www.branah.com/thai
>>
>> When I open this website in chrome, I do not see the dotted circles in
>> keyboard and
>> when top level thai characters are typed  nothing appears in text area.
>>
>> Using a sample application (facybroswer) dotted circle is seen in the
>> keyboard and when the top level thai characters are typed, it is seen
>> in the text area along with dotted circle.
>>
>> The Qt version used is Qt 4.7.4. I see the dotted circle was added in
>> harbuzz (harfbuzz old) bundled with Qt with the below patch,
>>
>> From 44f415aafaf7eec56b31468a58e0ca768bbc082d Mon Sep 17 00:00:00 2001
>> From: Jiang Jiang <jiang.jiang at nokia.com>
>> Date: Mon, 16 Jan 2012 15:39:56 +0100
>> Subject: [PATCH] Fix isolated Thai SARA AM handling
>>
>> If I remove this patch the dotted circle is not seen. But when the
>> first level vocal is entered nothing
>> appears in the text area and the application crashes.
>>
>> So my questions are,
>> 1) Is this dotted circle a standard feature in harbuzz or any qt web
>> browsers.
>> 2) Is it possbile to make the behaviour similar to chrome? Dotted
>> circle hidden and no characters should be seen when top level thai
>> characters are pressed.
>>
>> Thanks for any pointers.
>>
>> Regards,
>> Vignesh.
>> _______________________________________________
>> HarfBuzz mailing list
>> HarfBuzz at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/harfbuzz
>
>

-- 
Regards,
Vignesh.