From 81dc7996c60846038534315c40c9f5c1af824757 Mon Sep 17 00:00:00 2001
From: noppe <noppelabs@gmail.com>
Date: Wed, 4 Dec 2024 01:36:46 +0900
Subject: [PATCH] Use UIUpdateLink in iOS18

---
 Package.swift                                 |  6 +++
 .../BaseClass/AnimatableCGImageView.swift     | 42 +++++++++------
 Sources/UpdateLink/BackportUpdateLink.swift   | 54 +++++++++++++++++++
 .../DisplayLinkProxy.swift                    |  0
 Sources/UpdateLink/UIUpdateLink+.swift        | 15 ++++++
 Sources/UpdateLink/UpdateLink.swift           | 15 ++++++
 6 files changed, 117 insertions(+), 15 deletions(-)
 create mode 100644 Sources/UpdateLink/BackportUpdateLink.swift
 rename Sources/{AnimatedImage/Entity => UpdateLink}/DisplayLinkProxy.swift (100%)
 create mode 100644 Sources/UpdateLink/UIUpdateLink+.swift
 create mode 100644 Sources/UpdateLink/UpdateLink.swift

diff --git a/Package.swift b/Package.swift
index 397467d..001bd05 100644
--- a/Package.swift
+++ b/Package.swift
@@ -19,8 +19,14 @@ let package = Package(
     targets: [
         .target(
             name: "AnimatedImage",
+            dependencies: [
+                "UpdateLink"
+            ],
             resources: [.copy("Resources/PrivacyInfo.xcprivacy")]
         ),
+        .target(
+            name: "UpdateLink"
+        ),
         .target(
             name: "AnimatedImageSwiftUI",
             dependencies: [
diff --git a/Sources/AnimatedImage/BaseClass/AnimatableCGImageView.swift b/Sources/AnimatedImage/BaseClass/AnimatableCGImageView.swift
index f1fb0a2..459ae4d 100644
--- a/Sources/AnimatedImage/BaseClass/AnimatableCGImageView.swift
+++ b/Sources/AnimatedImage/BaseClass/AnimatableCGImageView.swift
@@ -1,28 +1,40 @@
 public import UIKit
+import UpdateLink
 
-open class AnimatableCGImageView: CGImageView, DisplayLinkTarget {
-    private var displayLink: CADisplayLink? = nil
+open class AnimatableCGImageView: CGImageView {
+    var updateLink: (any UpdateLink)!
     
-    open func startAnimating() {
-        stopAnimating()
-        displayLink = CADisplayLink(
-            target: DisplayLinkProxy(target: self),
-            selector: #selector(DisplayLinkProxy<Self>.updateContents)
+    public override init(frame: CGRect) {
+        super.init(frame: frame)
+        if #available(iOS 18.0, *) {
+            updateLink = UIUpdateLink(view: self)
+        } else {
+            updateLink = BackportUpdateLink(view: self)
+        }
+        updateLink.isEnabled = true
+        updateLink.preferredFrameRateRange = CAFrameRateRange(
+            minimum: 1,
+            maximum: 60
         )
-        displayLink?.preferredFrameRateRange = CAFrameRateRange(minimum: 1, maximum: 60)
-        displayLink?.add(to: .main, forMode: .common)
+        updateLink.addAction(handler: { [unowned self] _, info in
+            willUpdateContents(&contents, for: info.modelTime)
+        })
+        updateLink.requiresContinuousUpdates = true
     }
     
-    open func stopAnimating() {
-        displayLink?.invalidate()
-        displayLink = nil
+    @MainActor public required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
     }
     
-    func updateContents(_ displayLink: CADisplayLink) {
-        willUpdateContents(&contents, for: displayLink.targetTimestamp)
+    open func startAnimating() {
+        updateLink.isEnabled = true
+    }
+    
+    open func stopAnimating() {
+        updateLink.isEnabled = false
     }
     
     open func willUpdateContents(_ contents: inout CGImage?, for targetTimestamp: TimeInterval) {
-        
     }
 }
+
diff --git a/Sources/UpdateLink/BackportUpdateLink.swift b/Sources/UpdateLink/BackportUpdateLink.swift
new file mode 100644
index 0000000..2402787
--- /dev/null
+++ b/Sources/UpdateLink/BackportUpdateLink.swift
@@ -0,0 +1,54 @@
+import UIKit
+
+public final class BackportUpdateLink: UpdateLink, DisplayLinkTarget {
+    private var displayLink: CADisplayLink!
+    
+    public init(view: UIView) {
+        displayLink = CADisplayLink(
+            target: DisplayLinkProxy(target: self),
+            selector: #selector(DisplayLinkProxy<Self>.updateContents)
+        )
+    }
+    
+    public var isEnabled: Bool {
+        get { !displayLink.isPaused }
+        set { displayLink.isPaused = !newValue }
+    }
+    
+    public var requiresContinuousUpdates: Bool = false {
+        didSet {
+            if requiresContinuousUpdates {
+                displayLink.add(to: .main, forMode: .common)
+            } else {
+                displayLink.remove(from: .main, forMode: .common)
+            }
+        }
+    }
+    
+    public var preferredFrameRateRange: CAFrameRateRange {
+        get { displayLink?.preferredFrameRateRange ?? .default }
+        set { displayLink?.preferredFrameRateRange = newValue }
+    }
+    
+    private var handlers: [(any UpdateLink, any UpdateInfo) -> Void] = []
+    public func addAction(
+        handler: @escaping (any UpdateLink, any UpdateInfo) -> Void
+    ) {
+        handlers.append(handler)
+    }
+    
+    func updateContents(_ displayLink: CADisplayLink) {
+        let info = BackportUpdateInfo(modelTime: displayLink.targetTimestamp)
+        handlers.forEach { action in
+            action(self, info)
+        }
+    }
+}
+
+final class BackportUpdateInfo: UpdateInfo {
+    var modelTime: TimeInterval
+    
+    init(modelTime: TimeInterval) {
+        self.modelTime = modelTime
+    }
+}
diff --git a/Sources/AnimatedImage/Entity/DisplayLinkProxy.swift b/Sources/UpdateLink/DisplayLinkProxy.swift
similarity index 100%
rename from Sources/AnimatedImage/Entity/DisplayLinkProxy.swift
rename to Sources/UpdateLink/DisplayLinkProxy.swift
diff --git a/Sources/UpdateLink/UIUpdateLink+.swift b/Sources/UpdateLink/UIUpdateLink+.swift
new file mode 100644
index 0000000..7856f8e
--- /dev/null
+++ b/Sources/UpdateLink/UIUpdateLink+.swift
@@ -0,0 +1,15 @@
+import UIKit
+
+@available(iOS 18.0, *)
+extension UIUpdateInfo: UpdateInfo {}
+
+@available(iOS 18.0, *)
+extension UIUpdateLink: UpdateLink {
+    public func addAction(
+        handler: @escaping (any UpdateLink, any UpdateInfo) -> Void
+    ) {
+        addAction { (link: UIUpdateLink, info: UIUpdateInfo) in
+            handler(link, info)
+        }
+    }
+}
diff --git a/Sources/UpdateLink/UpdateLink.swift b/Sources/UpdateLink/UpdateLink.swift
new file mode 100644
index 0000000..e30bf28
--- /dev/null
+++ b/Sources/UpdateLink/UpdateLink.swift
@@ -0,0 +1,15 @@
+import UIKit
+
+@MainActor
+public protocol UpdateLink: AnyObject {
+    var isEnabled: Bool { get set }
+    var requiresContinuousUpdates: Bool { get set }
+    var preferredFrameRateRange: CAFrameRateRange { get set }
+    func addAction(handler: @escaping (any UpdateLink, any UpdateInfo) -> Void)
+}
+
+@MainActor
+public protocol UpdateInfo: AnyObject {
+    var modelTime: TimeInterval { get }
+}
+