Using Swift 2.x (for Swift 3.x, Swift 4.x and Swift 5.x read here below..) , i’ve found this fantastic article about C Callbacks in Swift.
Trying to obtain “all the CGPoint
(s)”, as explained by Lily Ballard, can be a bad idea as she said.
So, I think maybe the best way is to get the path elements points used to create a particular CGPath
:
//MARK: - CGPath extensions
extension CGPath {
func forEach(@noescape body: @convention(block) (CGPathElement) -> Void) {
typealias Body = @convention(block) (CGPathElement) -> Void
func callback(info: UnsafeMutablePointer<Void>, element: UnsafePointer<CGPathElement>) {
let body = unsafeBitCast(info, Body.self)
body(element.memory)
}
print(sizeofValue(body))
let unsafeBody = unsafeBitCast(body, UnsafeMutablePointer<Void>.self)
CGPathApply(self, unsafeBody, callback)
}
func getPathElementsPoints() -> [CGPoint] {
var arrayPoints : [CGPoint]! = [CGPoint]()
self.forEach { element in
switch (element.type) {
case CGPathElementType.MoveToPoint:
arrayPoints.append(element.points[0])
case .AddLineToPoint:
arrayPoints.append(element.points[0])
case .AddQuadCurveToPoint:
arrayPoints.append(element.points[0])
arrayPoints.append(element.points[1])
case .AddCurveToPoint:
arrayPoints.append(element.points[0])
arrayPoints.append(element.points[1])
arrayPoints.append(element.points[2])
default: break
}
}
return arrayPoints
}
}
With this extension you can do for example:
var bezier = UIBezierPath(ovalInRect: CGRectMake(0, 0, 400, 300))
let myOval = bezier.CGPath
let junctionPoints = myOval.getPathElementsPoints()
print("junction points are: \(junctionPoints)")
Swift 3.x and Swift 4.1 (look below for Swift 4.2 or major..)
(there are some corrections due to syntax re-introduction of @convention(c)
):
extension CGPath {
func forEach( body: @convention(block) (CGPathElement) -> Void) {
typealias Body = @convention(block) (CGPathElement) -> Void
let callback: @convention(c) (UnsafeMutableRawPointer, UnsafePointer<CGPathElement>) -> Void = { (info, element) in
let body = unsafeBitCast(info, to: Body.self)
body(element.pointee)
}
print(MemoryLayout.size(ofValue: body))
let unsafeBody = unsafeBitCast(body, to: UnsafeMutableRawPointer.self)
self.apply(info: unsafeBody, function: unsafeBitCast(callback, to: CGPathApplierFunction.self))
}
func getPathElementsPoints() -> [CGPoint] {
var arrayPoints : [CGPoint]! = [CGPoint]()
self.forEach { element in
switch (element.type) {
case CGPathElementType.moveToPoint:
arrayPoints.append(element.points[0])
case .addLineToPoint:
arrayPoints.append(element.points[0])
case .addQuadCurveToPoint:
arrayPoints.append(element.points[0])
arrayPoints.append(element.points[1])
case .addCurveToPoint:
arrayPoints.append(element.points[0])
arrayPoints.append(element.points[1])
arrayPoints.append(element.points[2])
default: break
}
}
return arrayPoints
}
func getPathElementsPointsAndTypes() -> ([CGPoint],[CGPathElementType]) {
var arrayPoints : [CGPoint]! = [CGPoint]()
var arrayTypes : [CGPathElementType]! = [CGPathElementType]()
self.forEach { element in
switch (element.type) {
case CGPathElementType.moveToPoint:
arrayPoints.append(element.points[0])
arrayTypes.append(element.type)
case .addLineToPoint:
arrayPoints.append(element.points[0])
arrayTypes.append(element.type)
case .addQuadCurveToPoint:
arrayPoints.append(element.points[0])
arrayPoints.append(element.points[1])
arrayTypes.append(element.type)
arrayTypes.append(element.type)
case .addCurveToPoint:
arrayPoints.append(element.points[0])
arrayPoints.append(element.points[1])
arrayPoints.append(element.points[2])
arrayTypes.append(element.type)
arrayTypes.append(element.type)
arrayTypes.append(element.type)
default: break
}
}
return (arrayPoints,arrayTypes)
}
}
Swift > 4.1 (also Swift 5.x) and iOS 9.x and > compatible
extension CGPath {
func forEach( body: @escaping @convention(block) (CGPathElement) -> Void) {
typealias Body = @convention(block) (CGPathElement) -> Void
let callback: @convention(c) (UnsafeMutableRawPointer, UnsafePointer<CGPathElement>) -> Void = { (info, element) in
let body = unsafeBitCast(info, to: Body.self)
body(element.pointee)
}
//print(MemoryLayout.size(ofValue: body))
let unsafeBody = unsafeBitCast(body, to: UnsafeMutableRawPointer.self)
self.apply(info: unsafeBody, function: unsafeBitCast(callback, to: CGPathApplierFunction.self))
}
func getPathElementsPoints() -> [CGPoint] {
var arrayPoints : [CGPoint]! = [CGPoint]()
self.forEach { element in
switch (element.type) {
case CGPathElementType.moveToPoint:
arrayPoints.append(element.points[0])
case .addLineToPoint:
arrayPoints.append(element.points[0])
case .addQuadCurveToPoint:
arrayPoints.append(element.points[0])
arrayPoints.append(element.points[1])
case .addCurveToPoint:
arrayPoints.append(element.points[0])
arrayPoints.append(element.points[1])
arrayPoints.append(element.points[2])
default: break
}
}
return arrayPoints
}
func getPathElementsPointsAndTypes() -> ([CGPoint],[CGPathElementType]) {
var arrayPoints : [CGPoint]! = [CGPoint]()
var arrayTypes : [CGPathElementType]! = [CGPathElementType]()
self.forEach { element in
switch (element.type) {
case CGPathElementType.moveToPoint:
arrayPoints.append(element.points[0])
arrayTypes.append(element.type)
case .addLineToPoint:
arrayPoints.append(element.points[0])
arrayTypes.append(element.type)
case .addQuadCurveToPoint:
arrayPoints.append(element.points[0])
arrayPoints.append(element.points[1])
arrayTypes.append(element.type)
arrayTypes.append(element.type)
case .addCurveToPoint:
arrayPoints.append(element.points[0])
arrayPoints.append(element.points[1])
arrayPoints.append(element.points[2])
arrayTypes.append(element.type)
arrayTypes.append(element.type)
arrayTypes.append(element.type)
default: break
}
}
return (arrayPoints,arrayTypes)
}
}