Re: [ft] i18n fonts

[Adam Twardoch]

Russell,

Unicode does not deal with text rendering -- this is another level. The 
character-to-glyph transformation is being done on a layout level. The 
most popular layout system is OpenType Layout. Then, the laid out glyph 
coordinates are passed to a rasterizer such as the Microsoft system 
rasterizer or such as FreeType.

This should be your first reading:
http://www.microsoft.com/typography/Glyph%20Processing/overview.mspx

The most popular OpenType Layout engines are Uniscribe (pre-installed on 
Windows, available through APIs), ICU Layout (opensource), 
Pango/HarfBuzz (opensource), Monotype WorldType (commercial), Bitstream 
Panorama (commercial). On Mac OS X, there is a number of text subsystems 
such as ATSUI or CoreText, but they only support OpenType Layout in a 
limited way (though the support was somewhat extended in Mac OS X 10.5).

A.


Russell Shaw wrote:
> Hi,
> I was thinking of making a multilingual text editor.
>
> I don't get how glyphs are done outside of english.
>
> I've read the Unicode Standard book.
>
> When a paragraph of unicode characters is processed, the glyphs
> are layed out according to the state contained in the unicode
> character sequence.
>
> Depending on this state, the same unicode characters can map to
> multiple glyphs depending on context.
>
> If multiple fonts exist for a language, then for all these font
> files to work with an editor, then all these glyphs must be indexed
> the same.
>
> Where can i find the standard that specifies what glyphs are indexed
> by what number? Or are these glyphs created on the fly by the unicode
> paragraph layout processor?
>
>
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--

Adam Twardoch
| Language Typography Unicode Fonts OpenType
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