[cairo] 4x4 matrices in Cairo

[Bill Spitzak]

Tavmjong Bah wrote:

> [1] http://www.w3.org/TR/css3-transforms/

This does seem to describe depth-buffer methods, thus requiring a 4x4 
matrix rather than a 3x3 one.

I am not really certain if Cairo should be trying to support that. Most 
of the compositing operators make no sense unless painter's algorithm is 
used for depth, and even OVER and so on will have trouble with antialiasing.

I cannot find anything in the document that says what is done with lines 
and fonts.