  By applying a compressive uniaxial deformation on the $\alpha-T_3$ lattice,
which interpolates between honeycomb lattice ($\alpha=0$) and dice lattice
($\alpha=1$), the Dirac cones move toward each other along a given direction,
merge and a gap opens while the flat band remains unchanged. Therefore, the
low-energy spectrum, along this merging direction, exhibits a transition from a
linear dispersion in the Dirac phase to a quadratic dispersion in the gapped
phase. However, along the perpendicular direction the spectrum remains linear.
Here we theoretically study the tunneling properties of particles through a
$\mathit{np}$ junction in deformed $\alpha-T_3$ lattice. In the Dirac phase, we
find that the tunneling properties are similar to those of undeformed
$\alpha-T_3$ lattice such as the perfect Klein tunneling at normal incidence
for all values of $\alpha$ and the total transparency of the junction, i.e. the
super-Klein tunneling, for $\alpha=1$ when the energy is equal to half of the
junction height. In the gapped phase, we obtain an opposite behavior when the
junction is oriented perpendicular to the deformation direction where the
perfect Klein tunneling turns into the anti-Klein tunneling effect for all
parameters $\alpha$ and the super-Klein tunneling effect transits to the
anti-super Klein tunneling effect, i.e. the junction is totally opaque.
