LearnBoost/node-canvas — pull request #166 by c-spencer (2012-05-02 18:36:08+00:00)
Title: TextMetrics API (partial)

I don't think it's possible for cairo to give an honest answer for `hangingBaseline`, `ideographicBaseline`, `fontBoundingBoxAscent` or `fontBoundingBoxDescent` without pango, so I've left those unimplemented rather than fudging the answer.

I also changed the calculation of the middle and bottom baselines. Before it was using `fe.height`, which can include external leading, whereas using `fe.ascent` and `fe.descent` won't.