  We consider circle patterns on surfaces with complex projective structures.
We investigate two symplectic forms pulled back to the deformation space of
circle patterns. The first one is Goldman's symplectic form on the space of
complex projective structures on closed surfaces. The other is the
Weil-Petersson symplectic form on the Teichm\"uller space of punctured
surfaces. We show that their pullbacks to the space of circle patterns
coincide. It is applied to prove the smoothness of the deformation space, which
is an essential step to the conjecture that the space of circle patterns is
homeomorphic to the Teichm\"uller space of the closed surface. We further
conjecture that the pullback of the symplectic forms is non-degenerate and
defines a symplectic structure on the space of circle patterns.
