[cairo] how to add some pdf optional content group in cairo

[李杨]

Hi, all
I now use cairolib to succesful create a pdf file with different vector
graphics , I search the cairolib and found no fucntion about the "Optional
Content Group" in pdf file, I want to create layers in pdf file.
So how to realize the optional group content basing the cairo lib? Is there
any material for reference?

thanks,
regrards,

-- 
Yang Li
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.cairographics.org/archives/cairo/attachments/20130131/023c4b25/attachment.html>