Herb Sutter, the chair of the ISO C++ standards commitee, sent out a message to the Cairo developers this week about their pursuit to potentially standardize a basic 2D drawing library for ISO C++. The committee right now is looking at using a C++-ified version of Cairo.
Cairo is not written in C++ but rather C, but the committee acknowledges the Cairo code is clean and very well structured. There would likely end up being a new C++ interface to Cairo as part of this work and they might end up using some of Cairo's documentation as part of their specification.
More details on the pursuit to utilize Cairo for standardized 2D drawing within a future version of ISO C++ can be found via the Cairo mailing list.