Ellipse.containsPoint

# for Ellipse class, assuming rotation increases in clockwise direction (negate rotation if not!)

# UNTESTED!
containsPoint: (p, withRotation=true) ->
  # "ellipse space" is the cartesian space
  # where the ellipse becomes the unit
  # circle centered at (0, 0)
  [x, y] = [p.x - @x, p.y - @y] # translate point into ellipse space
  if withRotation and @rotation # optionally rotate point into ellipse space
    c = Math.cos(@rotation)
    s = Math.sin(@rotation)
    [x, y] = [x*c + y*s, y*c + x*s]
  x = x / @width # scale point into ellipse space
  y = y / @height
  x*x + y*y <= 1 #if the resulting point falls on/in the unit circle at 0, 0