Add safe area constraints methods

Sources/Layout/UIKit/UIView+AutoLayout.swift

@@ -434,4 +434,57 @@ extension UIView {
             right.constraint(to: superview.margins.right, constant: -inset)
         ]
     }
+
+    // MARK: - Safe Area
+
+    /// Creates constraints aligning the edges of the receiver to the safe area of the superview with an inset.
+    ///
+    /// - Parameter inset: The inset value.
+    ///
+    /// - Returns: The created constraints.
+    public func safeAreaConstraints(
+        inset: CGFloat = 0
+    ) -> [NSLayoutConstraint] {
+        safeAreaConstraints(insets: UIEdgeInsets(top: inset, left: inset, bottom: inset, right: inset))
+    }
+
+    /// Creates constraints aligning the edges of the receiver to the safe area of the superview with directional insets
+    /// ([`NSDirectionalEdgeInsets`](https://developer.apple.com/documentation/uikit/nsdirectionaledgeinsets)).
+    ///
+    /// - Parameter insets: The directional insets.
+    ///
+    /// - Returns: The created constraints.
+    public func safeAreaConstraints(
+        insets: DirectionalInsets
+    ) -> [NSLayoutConstraint] {
+        assert(superview != nil, "safeAreaConstraints(insets:) requires superview")
+        guard let superview: UIView
+        else { return [] }
+        return [
+            leading.constraint(to: superview.safeArea.leading, constant: insets.leading),
+            trailing.constraint(to: superview.safeArea.trailing, constant: -insets.trailing),
+            top.constraint(to: superview.safeArea.top, constant: insets.top),
+            bottom.constraint(to: superview.safeArea.bottom, constant: -insets.bottom)
+        ]
+    }
+
+    /// Creates constraints aligning the edges of the receiver to the safe area of the superview with canonical insets
+    /// ([`UIEdgeInsets`](https://developer.apple.com/documentation/uikit/uiedgeinsets)).
+    ///
+    /// - Parameter insets: The canonical insets.
+    ///
+    /// - Returns: The created constraints.
+    public func safeAreaConstraints(
+        insets: CanonicalInsets
+    ) -> [NSLayoutConstraint] {
+        assert(superview != nil, "safeAreaConstraints(insets:) requires superview")
+        guard let superview: UIView
+        else { return [] }
+        return [
+            left.constraint(to: superview.safeArea.left, constant: insets.left),
+            right.constraint(to: superview.safeArea.right, constant: -insets.right),
+            top.constraint(to: superview.safeArea.top, constant: insets.top),
+            bottom.constraint(to: superview.safeArea.bottom, constant: -insets.bottom)
+        ]
+    }
 }

Tests/LayoutTests/UIKit/UIView+AutoLayoutTests.swift

@@ -987,4 +987,101 @@ final class UIViewAutoLayoutTests: XCTestCase {
         expect(constraints[0]).to(match(view.left.constraint(to: superview.margins.left, constant: inset)))
         expect(constraints[1]).to(match(view.right.constraint(to: superview.margins.right, constant: -inset)))
     }
+
+    // MARK: - Safe Area
+
+    func testSafeAreaConstraintsInset() {
+
+        // GIVEN
+
+        let superview: UIView = .init()
+        let view: UIView = .init()
+        superview.addSubview(view)
+
+        // WHEN
+
+        let constraints: [NSLayoutConstraint] = view.safeAreaConstraints()
+
+        // THEN
+
+        expect(constraints.count) == 4
+        expect(constraints[0]).to(match(view.left.constraint(to: superview.safeArea.left)))
+        expect(constraints[1]).to(match(view.right.constraint(to: superview.safeArea.right)))
+        expect(constraints[2]).to(match(view.top.constraint(to: superview.safeArea.top)))
+        expect(constraints[3]).to(match(view.bottom.constraint(to: superview.safeArea.bottom)))
+    }
+
+    func testSafeAreaConstraintsInset_givenInset() {
+
+        // GIVEN
+
+        let superview: UIView = .init()
+        let view: UIView = .init()
+        superview.addSubview(view)
+        let inset: CGFloat = 10
+
+        // WHEN
+
+        let constraints: [NSLayoutConstraint] = view.safeAreaConstraints(inset: inset)
+
+        // THEN
+
+        expect(constraints.count) == 4
+        expect(constraints[0]).to(match(view.left.constraint(to: superview.safeArea.left, constant: inset)))
+        expect(constraints[1]).to(match(view.right.constraint(to: superview.safeArea.right, constant: -inset)))
+        expect(constraints[2]).to(match(view.top.constraint(to: superview.safeArea.top, constant: inset)))
+        expect(constraints[3]).to(match(view.bottom.constraint(to: superview.safeArea.bottom, constant: -inset)))
+    }
+
+    func testSafeAreaConstraintsInsetsDirectional() {
+
+        // GIVEN
+
+        let superview: UIView = .init()
+        let view: UIView = .init()
+        superview.addSubview(view)
+        let insets: NSDirectionalEdgeInsets = .init(top: 1, leading: 2, bottom: 3, trailing: 4)
+
+        // WHEN
+
+        let constraints: [NSLayoutConstraint] = view.safeAreaConstraints(insets: insets)
+
+        // THEN
+
+        expect(constraints.count) == 4
+        expect(constraints[0])
+            .to(match(view.leading.constraint(to: superview.safeArea.leading, constant: insets.leading)))
+        expect(constraints[1])
+            .to(match(view.trailing.constraint(to: superview.safeArea.trailing, constant: -insets.trailing)))
+        expect(constraints[2])
+            .to(match(view.top.constraint(to: superview.safeArea.top, constant: insets.top)))
+        expect(constraints[3])
+            .to(match(view.bottom.constraint(to: superview.safeArea.bottom, constant: -insets.bottom)))
+    }
+
+    func testSafeAreaConstraintsInsetsCanonical() {
+
+        // GIVEN
+
+        let superview: UIView = .init()
+        let view: UIView = .init()
+        superview.addSubview(view)
+        let insets: UIEdgeInsets = .init(top: 1, left: 2, bottom: 3, right: 4)
+
+        // WHEN
+
+        let constraints: [NSLayoutConstraint] = view.safeAreaConstraints(insets: insets)
+
+        // THEN
+
+        expect(constraints.count) == 4
+        expect(constraints[0])
+            .to(match(view.left.constraint(to: superview.safeArea.left, constant: insets.left)))
+        expect(constraints[1])
+            .to(match(view.right.constraint(to: superview.safeArea.right, constant: -insets.right)))
+        expect(constraints[2])
+            .to(match(view.top.constraint(to: superview.safeArea.top, constant: insets.top)))
+        expect(constraints[3])
+            .to(match(view.bottom.constraint(to: superview.safeArea.bottom, constant: -insets.bottom)))
+    }
 }

cheatsheet.html

@@ -343,6 +343,12 @@ <h3>Margins</h3>
                         <pre>marginConstraints(insets: canonical)</pre>
                         <pre>sideMarginConstraints()</pre>
                         <pre>sideMarginConstraints(inset: 100)</pre>
+                        <h3>Safe Area</h3>
+                        <p>Constrains to superview safe area.<p>
+                        <pre>safeAreaConstraints()</pre>
+                        <pre>safeAreaConstraints(inset: 100)</pre>
+                        <pre>safeAreaConstraints(insets: directional)</pre>
+                        <pre>safeAreaConstraints(insets: canonical)</pre>
                         <h2>Auto Layout</h2>
                         <h3>NSLayoutConstraint</h3>
                         <pre>activate()</pre>