An image has vertices at $(1, 1)$, $(3, 1)$, and $(2, 4)$. If the image is subjected to a transformation matrix $T = \begin{pmatrix} 0.5 & 0 \\ 0 & 0.5 \end{pmatrix}$ followed by a shift of $\langle -1, 2 \rangle$, what are the coordinates of the new centroid?