Wraps (N, D) keypoints (D >= 2; first two columns x, y).
Extra columns (e.g. visibility / angle / scale) are carried through
geometric transforms unchanged; only the x, y coordinates move.
Parameters
dataTensor(N, D) with D >= 2; columns 0 and 1 are x and y.canvas_size(int, int)(H, W) of the image the points index into.