Fix the surface shadow with UICornerConfiguration on iOS 26

Examples/Maps-SwiftUI/Maps/MapsApp.swift

@@ -1,7 +1,7 @@
 // Copyright 2021 the FloatingPanel authors. All rights reserved. MIT license.
 
-import SwiftUI
 import FloatingPanel
+import SwiftUI
 
 @main
 struct MapsApp: App {
@@ -24,12 +24,12 @@ struct MapsApp: App {
 final class MapPanelCoordinator: FloatingPanelCoordinator {
     enum Event {}
 
-    let action: (Event) -> ()
+    let action: (Event) -> Void
     let proxy: FloatingPanelProxy
 
     private lazy var delegate: FloatingPanelControllerDelegate? = self
 
-    init(action: @escaping (Event) -> ()) {
+    init(action: @escaping (Event) -> Void) {
         self.action = action
         self.proxy = .init(controller: FloatingPanelController())
     }
@@ -42,51 +42,54 @@ final class MapPanelCoordinator: FloatingPanelCoordinator {
         contentHostingController.ignoresKeyboardSafeArea()
 
         if #available(iOS 16, *) {
-            // Set the delegate object
-            controller.delegate = delegate
-
-            // Set up the content
-            contentHostingController.view.backgroundColor = nil
-            controller.set(contentViewController: contentHostingController)
-
-            // Show the panel
-            controller.addPanel(toParent: mainHostingController, animated: false)
-        } else {
-            // NOTE: Fix floating panel content view constraints (#549)
-            // This issue happens on iOS 15 or earlier.
-
-            // Set the delegate object
-            controller.delegate = delegate
-
-            // Set up the content
-            contentHostingController.view.backgroundColor = nil
-            let contentWrapperViewController = UIViewController()
-            contentWrapperViewController.view.addSubview(contentHostingController.view)
-            contentWrapperViewController.addChild(contentHostingController)
-            contentHostingController.didMove(toParent: contentWrapperViewController)
-            controller.set(contentViewController: contentWrapperViewController)
-
-            // Show the panel
-            controller.addPanel(toParent: mainHostingController, animated: false)
-
-            contentHostingController.view.translatesAutoresizingMaskIntoConstraints = false
-            let bottomConstraint = contentHostingController.view.bottomAnchor.constraint(
-                equalTo: contentWrapperViewController.view.bottomAnchor
-            )
-            bottomConstraint.priority = .defaultHigh
-            NSLayoutConstraint.activate([
-                contentHostingController.view.topAnchor.constraint(
-                    equalTo: contentWrapperViewController.view.topAnchor
-                ),
-                contentHostingController.view.leadingAnchor.constraint(
-                    equalTo: contentWrapperViewController.view.leadingAnchor
-                ),
-                contentHostingController.view.trailingAnchor.constraint(
-                    equalTo: contentWrapperViewController.view.trailingAnchor
-                ),
-                bottomConstraint
-            ])
+            if #unavailable(iOS 26) {
+                // Set the delegate object
+                controller.delegate = delegate
+
+                // Set up the content
+                contentHostingController.view.backgroundColor = nil
+                controller.set(contentViewController: contentHostingController)
+
+                // Show the panel
+                controller.addPanel(toParent: mainHostingController, animated: false)
+                return
+            }
         }
+
+        // NOTE: Fix floating panel content view constraints (#549)
+        // This issue happens on iOS 15 or earlier, and iOS 26 or later.
+
+        // Set the delegate object
+        controller.delegate = delegate
+
+        // Set up the content
+        contentHostingController.view.backgroundColor = nil
+        let contentWrapperViewController = UIViewController()
+        contentWrapperViewController.view.addSubview(contentHostingController.view)
+        contentWrapperViewController.addChild(contentHostingController)
+        contentHostingController.didMove(toParent: contentWrapperViewController)
+        controller.set(contentViewController: contentWrapperViewController)
+
+        // Show the panel
+        controller.addPanel(toParent: mainHostingController, animated: false)
+
+        contentHostingController.view.translatesAutoresizingMaskIntoConstraints = false
+        let bottomConstraint = contentHostingController.view.bottomAnchor.constraint(
+            equalTo: contentWrapperViewController.view.bottomAnchor
+        )
+        bottomConstraint.priority = .defaultHigh
+        NSLayoutConstraint.activate([
+            contentHostingController.view.topAnchor.constraint(
+                equalTo: contentWrapperViewController.view.topAnchor
+            ),
+            contentHostingController.view.leadingAnchor.constraint(
+                equalTo: contentWrapperViewController.view.leadingAnchor
+            ),
+            contentHostingController.view.trailingAnchor.constraint(
+                equalTo: contentWrapperViewController.view.trailingAnchor
+            ),
+            bottomConstraint,
+        ])
     }
 
     func onUpdate<Representable>(

Sources/Extensions.swift

@@ -214,4 +214,73 @@ extension UIBezierPath {
                             cornerRadii: CGSize(width: cornerRadius,
                                                 height: cornerRadius))
     }
+
+    #if compiler(>=6.2)
+    @available(iOS 26.0, *)
+    static func path(roundedRect rect: CGRect, view: UIView) -> UIBezierPath {
+        // Apply inset to hide the gap between UIBezierPath's circular arcs
+        // and UICornerConfiguration's corner curves.
+        let rect = rect.insetBy(dx: 4, dy: 4)
+
+        // Query the effective corner radius from the view using the new iOS 26 API
+        // This properly handles UICornerConfiguration including .fixed, .dynamic, and .continuous
+        let topLeadingRadius = view.effectiveRadius(corner: .topLeft)
+        let topTrailingRadius = view.effectiveRadius(corner: .topRight)
+        let bottomLeadingRadius = view.effectiveRadius(corner: .bottomLeft)
+        let bottomTrailingRadius = view.effectiveRadius(corner: .bottomRight)
+
+        // Otherwise, create a path with individual corner radii
+        let path = UIBezierPath()
+        let minX = rect.minX
+        let minY = rect.minY
+        let maxX = rect.maxX
+        let maxY = rect.maxY
+
+        // Start from top left, after the corner
+        path.move(to: CGPoint(x: minX + topLeadingRadius, y: minY))
+
+        // Top edge and top-right corner
+        path.addLine(to: CGPoint(x: maxX - topTrailingRadius, y: minY))
+        if topTrailingRadius > 0 {
+            path.addArc(withCenter: CGPoint(x: maxX - topTrailingRadius, y: minY + topTrailingRadius),
+                       radius: topTrailingRadius,
+                       startAngle: -0.5 * .pi,
+                       endAngle: 0,
+                       clockwise: true)
+        }
+
+        // Right edge and bottom-right corner
+        path.addLine(to: CGPoint(x: maxX, y: maxY - bottomTrailingRadius))
+        if bottomTrailingRadius > 0 {
+            path.addArc(withCenter: CGPoint(x: maxX - bottomTrailingRadius, y: maxY - bottomTrailingRadius),
+                       radius: bottomTrailingRadius,
+                       startAngle: 0,
+                       endAngle: .pi * 0.5,
+                       clockwise: true)
+        }
+
+        // Bottom edge and bottom-left corner
+        path.addLine(to: CGPoint(x: minX + bottomLeadingRadius, y: maxY))
+        if bottomLeadingRadius > 0 {
+            path.addArc(withCenter: CGPoint(x: minX + bottomLeadingRadius, y: maxY - bottomLeadingRadius),
+                       radius: bottomLeadingRadius,
+                       startAngle: .pi * 0.5,
+                       endAngle: .pi,
+                       clockwise: true)
+        }
+
+        // Left edge and top-left corner
+        path.addLine(to: CGPoint(x: minX, y: minY + topLeadingRadius))
+        if topLeadingRadius > 0 {
+            path.addArc(withCenter: CGPoint(x: minX + topLeadingRadius, y: minY + topLeadingRadius),
+                       radius: topLeadingRadius,
+                       startAngle: .pi,
+                       endAngle: .pi * 1.5,
+                       clockwise: true)
+        }
+
+        path.close()
+        return path
+    }
+    #endif
 }

Sources/SurfaceView.swift

@@ -359,8 +359,23 @@ public class SurfaceView: UIView {
 
             let spread = shadow.spread
             let shadowRect = containerView.frame.insetBy(dx: -spread, dy: -spread)
-            let shadowPath = UIBezierPath.path(roundedRect: shadowRect,
+
+            // Create shadow path based on corner configuration or corner radius
+            let shadowPath: UIBezierPath
+            #if compiler(>=6.2)
+            if #available(iOS 26.0, *), appearance.cornerConfiguration != nil {
+                // Use UIView.effectiveRadius(corner:) API for iOS 26+
+                // This properly queries the actual corner radius from UICornerConfiguration
+                shadowPath = UIBezierPath.path(roundedRect: shadowRect, view: containerView)
+            } else {
+                shadowPath = UIBezierPath.path(roundedRect: shadowRect,
                                                appearance: appearance)
+            }
+            #else
+            shadowPath = UIBezierPath.path(roundedRect: shadowRect,
+                                           appearance: appearance)
+            #endif
+
             shadowLayer.shadowPath = shadowPath.cgPath
             shadowLayer.shadowColor = shadow.color.cgColor
             shadowLayer.shadowOffset = shadow.offset
@@ -369,17 +384,43 @@ public class SurfaceView: UIView {
             shadowLayer.shadowOpacity = shadow.opacity
 
             let mask = CAShapeLayer()
-            let path = UIBezierPath.path(roundedRect: containerView.frame,
-                                         appearance: appearance)
+
+            // Create mask path based on corner configuration or corner radius
+            let path: UIBezierPath
+            #if compiler(>=6.2)
+            if #available(iOS 26.0, *), appearance.cornerConfiguration != nil {
+                // Use UIView.effectiveRadius(corner:) API for iOS 26+
+                // This properly queries the actual corner radius from UICornerConfiguration
+                path = UIBezierPath.path(roundedRect: containerView.frame, view: containerView)
+            } else {
+                path = UIBezierPath.path(roundedRect: containerView.frame,
+                                        appearance: appearance)
+            }
+            #else
+            path = UIBezierPath.path(roundedRect: containerView.frame,
+                                    appearance: appearance)
+            #endif
+
             let size = window?.bounds.size ?? CGSize(width: 1000.0, height: 1000.0)
             path.append(UIBezierPath(rect: layer.bounds.insetBy(dx: -size.width,
                                                                 dy: -size.height)))
             mask.fillRule = .evenOdd
             mask.path = path.cgPath
+
+            #if compiler(>=6.2)
+            if #available(iOS 26.0, *), appearance.cornerConfiguration != nil {
+                // Corner curve is handled by UICornerConfiguration
+            } else if #available(iOS 13.0, *) {
+                containerView.layer.cornerCurve = appearance.cornerCurve
+                mask.cornerCurve = appearance.cornerCurve
+            }
+            #else
             if #available(iOS 13.0, *) {
                 containerView.layer.cornerCurve = appearance.cornerCurve
                 mask.cornerCurve = appearance.cornerCurve
             }
+            #endif
+
             shadowLayer.mask = mask
         }
         CATransaction.commit()