Returns whether this direction contains other. Specifically, a direction "D" contains another if D Direction2D.plus equals D. For example, NORTHEAST contains NORTH and EAST, but not WEST. All directions contain NONE. NONE contains only NONE.
Subtracts with a direction.
Sums with a direction.
Multiplies by a scalar.
Flips the direction horizontally and vertically.
Flips the direction's X-values.
Flips the direction's Y-values.