[XeTeX] "Options for all fonts" : colo[u]r, and the transparency byte

[Jonathan Kew]

On 5 Jun 2011, at 21:09, Peter Dyballa wrote:

> 
> Am 05.06.2011 um 21:54 schrieb Philip TAYLOR (Webmaster, Ret'd):
> 
>> So why doesn't it ?!
> 
> Phil,
> 
> it does! It passes all \special{}s without touching them into the output file. Whether you're using the xetex or the xelatex command plays no role: you have only access to the xetex engine's transparency support which is Mac OS X service oriented. This Mac OS X service transforms the \special{}s into PDF code.
> 
> The XeTeX engine needs to catch up with developments in PDF – or vanish. Could be LuaTeX and ConXeTeXt have a future.

I don't understand that.

Phil, the issue you're having is that the xetex option to specify transparency as part of the font colour does not use \special{} commands, it's an extra font property that is only supported by the (Mac-only, not-really-supported) xdv2pdf driver. Currently, at least, the xdvipdfmx driver - which is your only option on non-Mac systems - doesn't implement this.

On the other hand, it is *also* possible to specify transparency via PDF \special{}s. That's what I presume TikZ does, and apparently it works with xdvipdfmx. So you could do the same thing for text in plain xetex by writing the appropriate \special{} commands in your document. (But no, I don't know any details of exactly how to do that - sorry!)

JK