How to remove drawn CGPath after CGPathCreateMutable()?

Question

Ive wrote a few simple lines in swift 2.0 using SpriteKit to experiment using CGPathCreateMutable() to draw and creating lines shown below:

var lineNode = SKShapeNode()
var pathToDraw = CGPathCreateMutable()

 override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
   /* Called when a touch begins */

    for touch in touches {
        let location = touch.locationInNode(self)
        CGPathMoveToPoint(pathToDraw, nil, location.x, location.y)

        lineNode.path = pathToDraw
        lineNode.strokeColor = SKColor.redColor()
        self.addChild(lineNode)
        }
}

    override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
    for touch in touches {
        let positionInScene = touch.locationInNode(self)

        CGPathAddLineToPoint(pathToDraw, nil, positionInScene.x, positionInScene.y)
        lineNode.path = pathToDraw
        //pathToDraw
    }
}

    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {

    lineNode.removeFromParent()

}

A red path is drawn and then is removed after I lift my finger. I am able to remove the lineNode sprite. However I am not able to remove the path after drawing? When drawing the second line I am able to see the 'remnant' of the first path. If I keep drawing the app will crash. Ive found that it used to be removed by doing

 CGPathRelease(pathToDraw)  //in obj-C at least

but then Ive found out i no longer have to do this because it is an autonomous process?

How do I remove it? Thanks!

Moriya Moriya · Accepted Answer · 2015-10-23T01:22:16

You never reset the path and in the touches began callback you just add the next point. so to get rid of the old line just add

pathToDraw = CGPathCreateMutable()

to the end of

override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {

This will give you a new path to work with for the next line you draw

How to remove drawn CGPath after CGPathCreateMutable()?

1 Answers