  Vast tunable optical components are realized based on dynamic
reconfigurations of the incident wavefronts, such as beam steering and tunable
lens. However, the dominant paradigm of current wavefront reconfiguration
technologies relies on complex control systems with degrees of freedom much
larger than output wavefronts, e.g. beam steering based on spatial light
modulator or phased array antennas. Here, we propose a new paradigm for dynamic
reconfiguration of arbitrary output wavefronts using control systems with the
same degrees of freedom. As an example, a wavefront transformer is demonstrated
using an in-plane two-degree-of-freedom (2DOF) mechanical actuation system of
metasurface doublet for semi-omnidirectional beam steering, which measured a
6-kHz modulation speed and a "+-65.6 degree" field of view. This paradigm can
be applied to metasurface transformers for dynamic wavefront reconfiguration
with any control system for vast applications, such as tunable lens, beam
steering, and dynamic beam profiler, just to name a few.
