[cairo] 4x4 matrices in Cairo

James Cloos cloos at jhcloos.com
Fri Nov 15 05:36:34 PST 2013

>>>>> "BS" == Bill Spitzak <spitzak at gmail.com> writes:

JC>> Perspective transforms for 2D require arbitrary 3x3 matrices and [x,y,z]
JC>> vectors

BS> Actually the 3x3 matrix can only handle [x,y,1] vectors. The last
BS> number is the W, not the Z. The Z is effectively zero.

Yes, of course.  Poor copy editing. :(  I meant to write [x,y,w].

BS> I still think Cairo only needs to support 3x3 matrix though.

Indeed.  I tried to be explicit for the archives, but the intended thesis
was exactly that.

James Cloos <cloos at jhcloos.com>         OpenPGP: 1024D/ED7DAEA6

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