matt-curtis · December 22, 2020 20:47 · Dec 22, 2020 · Dec 22, 2020 · Dec 22, 2020 · Dec 22, 2020
diff --git a/1.Info.md b/1.Info.md
@@ -1 +1 @@
-# Playground demonstrating `CALayer.shadowPath`'s failure to overshoot when animated.
+# Playground demonstrating `CALayer.shadowPath`'s failure to overshoot when spring animated.
diff --git a/1.Info.md b/1.Info.md
@@ -0,0 +1 @@
+# Playground demonstrating `CALayer.shadowPath`'s failure to overshoot when animated.
diff --git a/2-PathsDontOvershoot.swift → 2.PathsDontOvershoot.swift b/2-PathsDontOvershoot.swift → 2.PathsDontOvershoot.swift
diff --git a/1-Info.md → 3.Also.md b/1-Info.md → 3.Also.md
@@ -1,3 +1 @@
-# Playground demonstrating `CALayer.shadowPath`'s failure to overshoot when animated.
-
 *(This is a deviation from the main issue, but there's also an issue where `CABasicAnimation.byValue` and `CABasicAnimation.isAdditive` are ignored when animating `CGPath` properties. When `UIViewPropertyAnimator` generates animations, they're additive by default, so this gap prevents proper support for `UIViewPropertyAnimator`-based animations of path properties. This issue is not demonstrated here, though — none of the code below makes uses of additive animations.)*
diff --git a/1-Info.md b/1-Info.md
@@ -1,3 +1,3 @@
 # Playground demonstrating `CALayer.shadowPath`'s failure to overshoot when animated.
 
-*(This is a deviation from the main issue, but there's also an issue where `CABasicAnimation.byValue` and `CABasicAnimation.isAdditive` are ignored when animating `CGPath` properties. When `UIViewPropertyAnimator` generates animations, they're additive by default, so this gap prevents proper support for `UIViewPropertyAnimator`-based animations of path properties)*
+*(This is a deviation from the main issue, but there's also an issue where `CABasicAnimation.byValue` and `CABasicAnimation.isAdditive` are ignored when animating `CGPath` properties. When `UIViewPropertyAnimator` generates animations, they're additive by default, so this gap prevents proper support for `UIViewPropertyAnimator`-based animations of path properties. This issue is not demonstrated here, though — none of the code below makes uses of additive animations.)*
diff --git a/1-Info.md b/1-Info.md
@@ -1,3 +1,3 @@
-# CALayer.shadowPath and CALayer.path don't overshoot when spring animated.
+# Playground demonstrating `CALayer.shadowPath`'s failure to overshoot when animated.
 
-This is a sidenote, but `CABasicAnimation.byValue` and `CABasicAnimation.isAdditive` are ignored when animating `CGPath`s (`path` or `shadowPath`).
+*(This is a deviation from the main issue, but there's also an issue where `CABasicAnimation.byValue` and `CABasicAnimation.isAdditive` are ignored when animating `CGPath` properties. When `UIViewPropertyAnimator` generates animations, they're additive by default, so this gap prevents proper support for `UIViewPropertyAnimator`-based animations of path properties)*
diff --git a/1-Info.md b/1-Info.md
@@ -0,0 +1,3 @@
+# CALayer.shadowPath and CALayer.path don't overshoot when spring animated.
+
+This is a sidenote, but `CABasicAnimation.byValue` and `CABasicAnimation.isAdditive` are ignored when animating `CGPath`s (`path` or `shadowPath`).
diff --git a/PathsDontOvershoot.swift → 2-PathsDontOvershoot.swift b/PathsDontOvershoot.swift → 2-PathsDontOvershoot.swift
diff --git a/PathsDontOvershoot.swift b/PathsDontOvershoot.swift
@@ -0,0 +1,69 @@
+import UIKit
+import PlaygroundSupport
+
+class View: UIView {
+
+	override init(frame: CGRect) {
+		super.init(frame: frame)
+
+		layer.shadowOpacity = 1
+		layer.shadowColor = UIColor.black.cgColor
+		layer.shadowOffset = .zero
+		layer.shadowRadius = 5
+
+		let startPath = UIBezierPath(
+			roundedRect: CGRect(
+				x: 75, y: 75,
+				width: 250, height: 250
+			),
+			byRoundingCorners: .allCorners,
+			cornerRadii: CGSize(width: 50, height: 50)
+		).cgPath
+
+		layer.shadowPath = startPath
+
+		let endPath = UIBezierPath(
+			roundedRect: CGRect(
+				x: 150, y: 150,
+				width: 100, height: 100
+			),
+			byRoundingCorners: .allCorners,
+			cornerRadii: CGSize(width: 25, height: 25)
+		).cgPath
+
+		DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(2)) {
+			let springAnimation = CASpringAnimation(keyPath: "shadowPath")
+
+			springAnimation.duration = springAnimation.settlingDuration
+
+			springAnimation.damping = 1
+
+			springAnimation.fromValue = startPath
+			springAnimation.toValue = endPath
+
+			self.layer.add(springAnimation, forKey: nil)
+
+			CATransaction.begin()
+			CATransaction.disableActions()
+
+			self.layer.shadowPath = endPath
+
+			CATransaction.commit()
+		}
+	}
+
+	required init?(coder: NSCoder) {
+		fatalError("init(coder:) has not been implemented")
+	}
+
+}
+
+let backgroundView = UIView(frame: CGRect(x: 0, y: 0, width: 400, height: 400))
+
+backgroundView.backgroundColor = .white
+
+let shadowOnlyView = View(frame: CGRect(x: 0, y: 0, width: 400, height: 400))
+
+backgroundView.addSubview(shadowOnlyView)
+
+PlaygroundPage.current.liveView = backgroundView
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		# Playground demonstrating `CALayer.shadowPath`'s failure to overshoot when animated.
		# Playground demonstrating `CALayer.shadowPath`'s failure to overshoot when spring animated.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		# Playground demonstrating `CALayer.shadowPath`'s failure to overshoot when animated.
Original file line number	Diff line number	Diff line change
		@@ -1,3 +1 @@
		# Playground demonstrating `CALayer.shadowPath`'s failure to overshoot when animated.

		(This is a deviation from the main issue, but there's also an issue where `CABasicAnimation.byValue` and `CABasicAnimation.isAdditive` are ignored when animating `CGPath` properties. When `UIViewPropertyAnimator` generates animations, they're additive by default, so this gap prevents proper support for `UIViewPropertyAnimator`-based animations of path properties. This issue is not demonstrated here, though — none of the code below makes uses of additive animations.)
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		# CALayer.shadowPath and CALayer.path don't overshoot when spring animated.

		This is a sidenote, but `CABasicAnimation.byValue` and `CABasicAnimation.isAdditive` are ignored when animating `CGPath`s (`path` or `shadowPath`).