UIBezierPath Scaling

I've written this function to attempt to scale UIBezierPaths that I have as they are being drawn...

  func fit(into:CGRect) -> Self {
    let bounds = self.cgPath.boundingBox

    let sw     = into.size.width/bounds.width
    let sh     = into.size.height/bounds.height


    let factor = min (5, min(sw, max(sh, 0.0)))

    return scale(x: factor, y: factor, into: into)
  }

It works ok. The problem however exists. There are dashes inbetween points sometimes. If I'm not making sense please tell me and I'll try to rephrase my question.