性能分析、修复和验证：利用 Instruments 提升 App 响应性

5:41 - Add signpost interval around Lasso Selection

// Add signpost interval around Lasso Selection

import os.signpost

let signposter = OSSignposter(subsystem: “Demo App", category: .pointsOfInterest)
var lassoIntervalState: OSSignpostIntervalState? = nil

func lassoSelectionUpdated() {
    lassoIntervalState = signposter.beginInterval("Lasso Selection")
    // Update selection in canvas…
}

func lassoSelectionEnded() {
    // Finalize lasso selection...
    signposter.endInterval("Lasso Selection", lassoIntervalState!)
}

12:11 - Existentials

// Existentials

protocol Foo { }

struct TypeA: Foo { }
struct TypeB: Foo { }

func bar(_ foo: any Foo) {

}

12:39 - Concrete Types

// Concrete types

protocol Foo { }

struct TypeA: Foo { }
struct TypeB: Foo { }

func bar(_ a: TypeA) {

}

func bar(_ b: TypeB) {

}

12:46 - Concrete Types + Generics

// Concrete types

protocol Foo { }

struct TypeA: Foo { }
struct TypeB: Foo { }

func bar(_ a: TypeA) {

}

func bar(_ b: TypeB) {

}

// Generics

protocol Foo { }

struct TypeA: Foo { }
struct TypeB: Foo { }

func bar<T: Foo>(_ generic: T) {

}

12:49 - Concrete Types + Generics + Enums

// Concrete types

protocol Foo { }

struct TypeA: Foo { }
struct TypeB: Foo { }

func bar(_ a: TypeA) {

}

func bar(_ b: TypeB) {

}

// Generics

protocol Foo { }

struct TypeA: Foo { }
struct TypeB: Foo { }

func bar<T: Foo>(_ generic: T) {

}

// Enums

enum Foo {
    case a(TypeA)
    case b(TypeB)
}

struct TypeA { }
struct TypeB { }

func bar(_ enum: Foo) {

}

18:24 - Thumbnail Rendering

// Thumbnail rendering

let drawingData = note.drawingData
let canvasImages = note.decodeCanvas()
thumbnail = await Task(name: "Render Thumbnail") {
    await renderThumbnail(drawingData: drawingData, canvasImages: canvasImages, size: CGSize(width: 300, height: 240))
}.value

18:29 - Thumbnail Rendering Off Main Actor

// Thumbnail rendering off Main Actor

let drawingData = note.drawingData
let canvasImages = note.decodeCanvas()
thumbnail = await Task(name: "Render Thumbnail") { @concurrent in
    await renderThumbnail(drawingData: drawingData, canvasImages: canvasImages, size: CGSize(width: 300, height: 240))
}.value

24:12 - File Saving

// File saving

let encoder = PropertyListEncoder()
encoder.outputFormat = .binary
guard let data = try? encoder.encode(snapshots) else { return }
let id = signposter.beginInterval("Writing To File")
try? data.write(to: fileURL, options: .atomic)
signposter.endInterval("Writing To File", id)

24:25 - File Saving off Main thread

// File saving

Task { @concurrent in
	let encoder = PropertyListEncoder()
	encoder.outputFormat = .binary
	guard let data = try? encoder.encode(snapshots) else { return }
	let id = signposter.beginInterval("Writing To File")
	try? data.write(to: fileURL, options: .atomic)
	signposter.endInterval("Writing To File", id)
}