[HarfBuzz] Dotted circles in harfbuzz

[Vignesh Raman]

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.