Add transparency functions to the trace device.
Add transparency functions to the trace device.

Ignore-this: fcc3a073d42953c19765d522d26ef305

darcs-hash:20100714011554-f546f-5fc3bc3f1f6d5fe2fa6a8bb7df1399807345b603.gz

nqv/mupdf,nqv/mupdf,nqv/mupdf,nqv/mupdf,nqv/mupdf,nqv/mupdf