  Resonantly forced spiral waves in excitable media drift in straight-line
paths, their rotation centers behaving as point-like objects moving along
trajectories with a constant velocity. Interaction with medium boundaries
alters this velocity and may often result in a reflection of the drift
trajectory. Such reflections have diverse characteristics and are known to be
highly nonspecular in general. In this context we apply the theory of response
functions, which via numerically computable integrals, reduces the
reaction-diffusion equations governing the whole excitable medium to the
dynamics of just the rotation center and rotation phase of a spiral wave.
Spiral reflection trajectories are computed by this method for both small- and
large-core spiral waves in the Barkley model. Such calculations provide insight
into the process of reflection as well as explanations for differences in
trajectories across parameters, including the effects of incidence angle and
forcing amplitude. Qualitative aspects of these results are preserved far
beyond the asymptotic limit of weak boundary effects and slow resonant drift.
