cairo:matrix-translate (matrix tx ty)

matrix -- a cairo:matrix-t instance
tx -- a number coerced to a double float for the amount to tanslate in the x direction
ty -- a number coerced to a double float for the amount to tanslate in the y direction

The cairo:matrix-t instance with the applied translation.

Applies a translation by tx, ty to the transformation in the matrix. The effect of the new transformation is to first translate the coordinates by tx and ty, then apply the original transformation to the coordinates.