[HarfBuzz] Harfbuzz version

[Behdad Esfahbod]

Check:

  http://www.ecma-international.org/publications/techreports/E-TR-053.htm

behdad

On 11/17/10 14:33, Chris Scaife wrote:
> Thanks for reading my posts :)
> 
> Currently all terminals have control sequences that are based on left to
> right. I want to create an enhanced low level with bidirectional
> controls: plot glyph and move left, plot glyph and move right, return to
> left margin - return to right margin, erase to end of line left and
> erase to end of line right etc.
> 
> The Unicode algorithm is probably fine from the user's perspective, but
> at the display level in a terminal or terminal emulator one needs to
> know at least which margin a line is anchored on and be able to index a
> character by position on that line: It is not practical to scan what is
> recorded for each line while reversing the Unicode algorithm as we go.
> 
> Thus I felt I cannot work with a widget like GtkTextView and other
> display widgets that have integral Unicode bidi to render their display.
> 
> On 18 November 2010 07:49, Behdad Esfahbod <behdad at behdad.org
> <mailto:behdad at behdad.org>> wrote:
> 
>     On 11/12/10 16:36, Chris Scaife wrote:
>     > Thanks for that reply :)
>     > I did indeed look at using Cairo/Pango but I was really struggling
>     with
>     > them. A lot of this was due to the integral Unicode bidi algorithm
>     that
>     > makes it nearly impossible for me to know where any particular
>     character
>     > is being placed.
> 
>     Not as much as you make it sound.
> 
> 
>     > Thus at the low level I want to do a much simpler bidi algorithm
>     with an
>     > expicit LRE/RLE for every direction change. Indeed I recently did drop
>     > down to Xft but now having a hard time using it with Gtk and still
>     > unable to understand how the font is selected e.g. you can see
>     images of
>     > the problem plotting Chinese and Arabic
> 
>     I  strongly recommend against making up your own bidi algorithm...
> 
> 
>     behdad
> 
> 
>     > I suppose the main thing is that it's all good learning experience and
>     > perhaps when I actually know enough I'll be able to make a genuine
>     > contribution on the vte widget :) When I got the source code for it a
>     > while back I got hopelessly lost :(
>     >
>     > On 13 November 2010 10:11, Behdad Esfahbod <behdad at behdad.org
>     <mailto:behdad at behdad.org>
>     > <mailto:behdad at behdad.org <mailto:behdad at behdad.org>>> wrote:
>     >
>     >     On 11/12/10 15:48, Chris Scaife wrote:
>     >     > Hello all,
>     >
>     >     Hi Chris, welcome to the list.
>     >
>     >     > I am writing a terminal emulator as an learning experience
>     and would
>     >     > like to do a comprehensive implementation.
>     >
>     >     Humm.  Being the maintainer of 'vte' myself, may I suggest
>     that you
>     >     consider
>     >     studying the vte code and contribute there?  We can use a
>     couple hands.
>     >
>     >     > For compatibility with things
>     >     > like ncurses I need to have full control of glyph
>     positioning and so I
>     >     > feel my best option might be to interface the font stack through
>     >     Harfbuzz.
>     >     >
>     >     > Where can I find a Harfbuzz distribution and description of the
>     >     current
>     >     > API that I can use with my project please?
>     >
>     >     Unless you want to support Indic, Arabic, etc, it would be
>     easier to
>     >     just use
>     >     something like cairo or Xft directly.  If you still rather use
>     >     HarfBuzz, well,
>     >     this is the one paragraph summary:
>     >
>     >    
>      http://lists.freedesktop.org/archives/harfbuzz/2010-October/000905.html
>     >
>     >
>     >     Cheers,
>     >     behdad
>     >
>     >     > Thanks in advance
>     >     > Chris
>     >
>     >
> 
>