How to loop through point in UIBezierPath swift? - ios

Question

How can I loop through the circle UIBezierPath coordinates so I can move the dot object over the circular path when the user moves their finger on the screen? (kind of like a virtual combination lock)
let blueDotCategoryName = "blue"
var blueDot = SKSpriteNode()
//...
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
/* Called when a touch begins */
let touch = touches.anyObject() as UITouch
let touchLocation = touch.locationInNode(self)
let node = self.nodeAtPoint(touchLocation)
if node.name == blueDotCategoryName {
fingerIsOn = true
}
}
override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {
if fingerIsOn {
let touch = touches.anyObject() as UITouch
let touchLocation = touch.locationInNode(self)
let prevTouchLocation = touch.previousLocationInNode(self)
let blueDot = self.childNodeWithName(blueDotCategoryName) as SKSpriteNode
// var newPosition = coordinates in circle UIBezierPath
// blueDot.position = ...
}
/*
var circle = UIBezierPath()
circle.addArcWithCenter(CGPoint(x: 0, y: 0), radius: (self.frame.width / 6.7), startAngle: 0, endAngle: 360, clockwise: true)
*/
}
override func touchesEnded(touches: NSSet, withEvent event: UIEvent) {
fingerIsOn = false
}

Answer 1

There is no built-in method to do this for you, so you'll have to write it yourself. It will probably be easier if you create the bezier path as a series of line segments (and if they're reasonably close enough to each other, it will be indistinguishable from the original path).
Having said that, given your description (a "virtual combination lock"), I wonder if there aren't some third party complex gesture recognizers that might simplify the whole process for you:
$1 Unistroke Recognizer - A unistroke recognizer of complex gestures.
You might also consider GLGestureRecognizer, an Objective-C implementation.
$N Multistroke Recognizer - A multistroke version of the $1 Unistroke Recognizer
This is discussed in some detail in Complex Gesture Recognition in iOS.
These might jump start your efforts.