  Spin wave, the collective excitation of magnetic order, is one of the
fundamental angular momentum carriers in magnetic systems. Understanding the
spin wave propagation in magnetic textures lies in the heart of developing pure
magnetic information processing schemes. Here we show that the spin wave
propagation across a chiral domain wall follows simple geometric trajectories,
similar to the geometric optics. And the geometric behaviors are qualitatively
different in normally magnetized film and tangentially magnetized film. We
identify the lateral shift, refraction, and total reflection of spin wave
across a ferromagnetic domain wall. Moreover, these geometric scattering
phenomena become polarization-dependent in antiferromagnets, indicating the
emergence of spin wave birefringence inside antiferromagnetic domain wall.
