Reflects the column carrying an axis role and flips its declared
direction, so the data describes the same scene with the axis pointing
the other way — for example converting image coordinates, where y runs
down, to a y that runs up.
An axis runs from zero to its extent, so turning it over gives
new = extent - old. An axis with no declared axis_extents is centred
on its origin, and turning it over negates it. On a frame that stores
angles there is no column to reflect, and phi and theta are
recomputed instead.
A declared handedness flips with any linear axis.
Examples
af <- example_anipoint(n_obs = 3, n_individuals = 1, n_keypoints = 1)
af <- set_metadata(af, axis_extents = c(y = 1080))
af <- set_axis_directions(af, c(x = "right", y = "down"))
af <- reflect_axis(af, "y")
get_axis_directions(af)
#> x y
#> "right" "up"