Re: Dotted Circle plus Combining Mark as Text

On Mon, 21 Oct 2013 10:24:41 +1100
Andrew Cunningham <lang.support_at_gmail.com> wrote:

> I suspect it is a font issue, rather than a renderer issue, but then
> using a dotted circle is a convention used in the unicode charts and
> in the unicode spec.

The extra dotted circles are a layout engine issue at least in part.
On Windows, one can choose whether Firefox uses Uniscribe or HarfBuzz.
I don't know the granularity of the choice, but it seems to be on a
script by script basis. If I choose HarfBuzz for all scripts, the
unwanted dotted circles vanish.

However, I'm not sure how much Uniscribe is actually to blame. If the
default grapheme cluster <U+25CC, U+0E31> is being split between script
runs, the fault will arguably lie with whatever does the splitting. A
string starting U+0E31 will start to the left of the origin of the
string unless something is inserted before it, albeit a space.

> It is not a combination I'd expect a font
> developer from SE Asia to necessarily support.

> Since publications in SE Asia have their own typographic conventions
> for displaying isolated combining marks.

The usual Thai convention of using a dash as the place holder also suffers from layout engines inserting dotted circles.

Richard.
Received on Sun Oct 20 2013 - 19:14:59 CDT