John Jenkins wrote:
> On Dec 1, 2003, at 4:24 PM, Frank Yung-Fong Tang wrote: > > > John What 'cmap' format Apple use in the MacOS X > > Devanagari and Bangla fonts? > > > > The formats are irrelevant; the Mac supports all the 'cmap' subtable > formats for all subtables. For rendering complex scripts, however, the > font can only be rendered through ATSUI (or Cocoa), because the old way > to support complex scripts â via an 'itl5' resource in the suitcase > with the 'FOND' and 'sfnt' resources â is not supported on X. It may or may not relevant. The reason I ask this question is because the eariler version of mozilla code (I forgot when do we change it) used to work around a "freezing" issue on ATSUI on the eariler version of MacOS X. What happen is in the old version of MacOS X, if a page of Unicode characters are not supported by any installed font, the performance is extermley unacceptable (freeze for 3 minutes by open and close font file) in Mozilla because either the old MacOSX does not cache the information about which characters have no glyph on the system at all or such caching is based on the layout instead of a global. To work around that, Mozilla read the cmap table (only some format) to decide which chracters 'could be render" by ATSUI before it pass to ATSUI. I know the performance is much better now (wel... if you are still not sure, try to visit http://people.netscape.com/ftang/testscript/gb18030/gbtext.cgi?page=1220 a page of GB18030 characters which encode Unicode plane 4 (which have no characters assign yet) from a browser which support GB18030. or http://people.netscape.com/ftang/testscript/gb18030/gb18030.cgi?page=1220 for the html which include NCR, GB18030 and GIF (which does not exist) I think we remove that checking code last year, after the newer version of MacOS X improve from this "almost freeze with wrong data" situration. > > Apple really, really wants everybody to move to using Unicode in their > applications for all their text, and Apple really, really, *really* > wants people to do it for complex scripts. And my question have no conflict with Apple's recommendation at all. Think about this, while Microsoft support Unicode cmap and really encourage people to use Unicode, they ALSO publish the WGL4 and the OpenType font spec for different script. They also say which format a font SHOULD support in TTF cmap. That does not conflict with the goal of "Using Unicode" at all. There are times people have to know those details. And it is better those details are capture in a Apple's public tech note, rather than people dig into the code by revers eng and guess what it is. For example, if I want to customize my "last resort" behavior in MacOS X with ATSUI (by drawing a Frank Tang picture with a Unicode Decimal value below it- a way nobody want to implement- everyone live Unicode Hex, right. Just want to make an extreme case that for sure John won't crazy enough to add them into ATSUI.) in my application, how can I do it now? -- -- Frank Yung-Fong Tang ÅÃÅtÃm ÃrÃhÃtÃÃt, IÃtÃrnÃtiÃnÃl DÃvÃlÃpmeÃt, AOL IntÃrÃÃtÃvà SÃrviÃes AIM:yungfongta mailto:[EMAIL PROTECTED] Tel:650-937-2913 Yahoo! Msg: frankyungfongtan
