Given a 2D path, this function constructs a mid-point smoothed version by joining the mid-points of the lines of the path.
**Since:** 1.3
## Parameters
-`points` : The path points.
-`n` : Perform mid-point smoothing n times.
-`closed` : Is the points a 2D shape? If it's `true`, the function takes the last point and the first one to calculate a middle point. Default to `false`.