Re: [Libreoffice] Need to add Arabic Math Symbols to LibreOffice Math

On Thu, Sep 15, 2011 at 11:53:22AM +0100, Caolán McNamara wrote:
> On Wed, 2011-09-14 at 03:37 +0200, Ibraheem Saed wrote:
> > Hello everybody,
> >
> > LibreOffice Math doesn't support Arabic math symbols.
> >
> > I need to add the Arabic math symbols to "LibreOffice Math" Aligned
> > from right to left.
> >
> > Arabic math symbols like are English math symbols; but writing is
> > reversed (from right to left and symbols are opposite).
>
>
> Hmmm, Unicode technical report #25 seems to be the relevant
> documentation around this. 
>
> http://www.unicode.org/Public/5.2.0/ucd/BidiMirroring.txt for the right
> to left forms which can be synthesized from existing unicode code points
>
> And the opentype "rtlm" table for including right to left forms in the
> font itself.
>
> It *looks* to me on a casual look through, that some support in our text
> rendering would be needed to take the text to be rendered, look up if
> the font has a rtlm mapping for the glyph, and if it doesn't then see if
> the font has a glyph for its BidiMirroring equivalent, and if not then
> try and just swap the glyph around ?

We need more than mirroring bidi mirrored glyphs, we need also to be
able to lay the whole formula from right to left (including things like
sub and superscripts which ave to be on the left of base node) and apply
bidi algorithm to individual tokens and not the whole formula. This W3
note gives an overview of laying out Arabic mathematical notation:

http://www.w3.org/TR/arabic-math/

Also MathML3 now supports right to left math:
http://www.w3.org/TR/MathML3/chapter3.html#presm.bidi

On the other hand, LO's math rendering is quite boor compared to TeX,
latest version of MS Word (which has a formula renderer based on TeX
algorithms) or even Mozilla's. For their Office 2007, MS developed and
new OpenType table, (MATH, implemented in their Cambria font) which can
be seen as a modernisation of TeX concepts. There few free
implementations of OpenType MATH and implementing it in LO would give it
higher quality math layout and support for increasing number of OpenType
math fonts.

Regards,
 Khaled

-- 
 Khaled Hosny
 Egyptian
 Arab