如何获得包含在给定 CGPath
(CGMutablePathRef
) 中的所有 CGPoint
的数组?
最佳答案
使用 Swift 2.x(适用于 Swift 3.x、Swift 4.x 和 Swift 5.x 在下面阅读..) ,我发现了这篇关于 C Callbacks in Swift 的精彩文章.
尝试获取“所有 CGPoint
(s)”,如 Lily Ballard 所解释的那样,正如她所说,这可能是个坏主意。
所以,我认为也许最好的方法是获取用于创建特定 CGPath
的路径元素点:
//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
}
}
使用此扩展程序,您可以执行以下操作:
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 和 Swift 4.1(查看下面的 Swift 4.2 或主要..)
(由于 @convention(c)
的语法重新引入,有一些更正):
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(也与 Swift 5.x)和 iOS 9.x 兼容
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)
}
}
关于iphone - 如何获取 CGPath 的 CGPoint,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12992462/