Initial Commit

Sources/TextualAutoLayout/TextualAutoLayout.swift

@@ -0,0 +1,124 @@
+#if os(macOS)
+import AppKit
+public typealias ConstraintPriority = NSLayoutConstraint.Priority
+public typealias ConstraintAxis = NSLayoutConstraint.Orientation
+public typealias ConstraintView = NSView
+#else
+import UIKit
+public typealias ConstraintPriority = UILayoutPriority
+public typealias ConstraintAxis = NSLayoutConstraint.Axis
+public typealias ConstraintView = UIView
+#endif
+
+/*
+  Readable Auto Layout Constraints
+
+  Usage:
+    A.anchor =&= multiplier * B.anchor + constant | priority
+*/
+
+precedencegroup ReadableLayoutPrecedence {
+	higherThan: AdditionPrecedence
+	lowerThan: MultiplicationPrecedence
+}
+
+infix operator =&= : ReadableLayoutPrecedence
+infix operator =<= : ReadableLayoutPrecedence
+infix operator =>= : ReadableLayoutPrecedence
+
+/// Create and activate an `equal` constraint between left and right anchor. Format: `A.anchor =&= multiplier * B.anchor + constant | priority`
+@discardableResult public func =&= <T>(l: NSLayoutAnchor<T>, r: NSLayoutAnchor<T>) -> NSLayoutConstraint { l.constraint(equalTo: r).on() }
+/// Create and activate a `lessThan` constraint between left and right anchor. Format: `A.anchor =<= multiplier * B.anchor + constant | priority`
+@discardableResult public func =<= <T>(l: NSLayoutAnchor<T>, r: NSLayoutAnchor<T>) -> NSLayoutConstraint { l.constraint(lessThanOrEqualTo: r).on() }
+/// Create and activate a `greaterThan` constraint between left and right anchor. Format: `A.anchor =>= multiplier * B.anchor + constant | priority`
+@discardableResult public func =>= <T>(l: NSLayoutAnchor<T>, r: NSLayoutAnchor<T>) -> NSLayoutConstraint { l.constraint(greaterThanOrEqualTo: r).on() }
+
+public extension NSLayoutDimension { // higher precedence, so multiply first
+	/// Create intermediate anchor multiplier result.
+	static func *(l: CGFloat, r: NSLayoutDimension) -> AnchorMultiplier { .init(anchor: r, m: l) }
+	/// Create and activate an `equal` constraint with constant value. Format: `A.anchor =&= constant | priority`
+	@discardableResult static func =&=(l: NSLayoutDimension, r: CGFloat) -> NSLayoutConstraint { l.constraint(equalToConstant: r).on() }
+	/// Create and activate a `lessThan` constraint with constant value. Format: `A.anchor =<= constant | priority`
+	@discardableResult static func =<=(l: NSLayoutDimension, r: CGFloat) -> NSLayoutConstraint { l.constraint(lessThanOrEqualToConstant: r).on() }
+	/// Create and activate a `greaterThan` constraint with constant value. Format: `A.anchor =>= constant | priority`
+	@discardableResult static func =>=(l: NSLayoutDimension, r: CGFloat) -> NSLayoutConstraint { l.constraint(greaterThanOrEqualToConstant: r).on() }
+}
+
+/// Intermediate `NSLayoutConstraint` anchor with multiplier supplement
+public struct AnchorMultiplier {
+	fileprivate let anchor: NSLayoutDimension, m: CGFloat
+}
+
+public extension AnchorMultiplier {
+	/// Create and activate an `equal` constraint between left and right anchor. Format: `A.anchor =&= multiplier * B.anchor + constant | priority`
+	@discardableResult static func =&=(l: NSLayoutDimension, r: Self) -> NSLayoutConstraint { l.constraint(equalTo: r.anchor, multiplier: r.m).on() }
+	/// Create and activate a `lessThan` constraint between left and right anchor. Format: `A.anchor =<= multiplier * B.anchor + constant | priority`
+	@discardableResult static func =<=(l: NSLayoutDimension, r: Self) -> NSLayoutConstraint { l.constraint(lessThanOrEqualTo: r.anchor, multiplier: r.m).on() }
+	/// Create and activate a `greaterThan` constraint between left and right anchor. Format: `A.anchor =>= multiplier * B.anchor + constant | priority`
+	@discardableResult static func =>=(l: NSLayoutDimension, r: Self) -> NSLayoutConstraint { l.constraint(greaterThanOrEqualTo: r.anchor, multiplier: r.m).on() }
+}
+
+public extension NSLayoutConstraint {
+	/// Change `isActive`to `true` and return `self`
+	func on() -> Self { isActive = true; return self }
+	/// Change `isActive`to `false` and return `self`
+	func off() -> Self { isActive = false; return self }
+	/// Change `constant`attribute  and return `self`
+	@discardableResult static func +(l: NSLayoutConstraint, r: CGFloat) -> NSLayoutConstraint { l.constant = r; return l }
+	/// Change `constant` attribute and return `self`
+	@discardableResult static func -(l: NSLayoutConstraint, r: CGFloat) -> NSLayoutConstraint { l.constant = -r; return l }
+	/// Change `priority` attribute and return `self`
+	@discardableResult static func |(l: NSLayoutConstraint, r: ConstraintPriority) -> NSLayoutConstraint { l.priority = r; return l }
+}
+
+/*
+  UIView extension to generate multiple constraints at once
+
+  Usage:
+    child.anchor([.width, .height], to: parent) | .defaultLow
+*/
+
+public extension ConstraintView {
+	#if os(macOS)
+	/// Edges that need the relation to flip arguments. For these we need to inverse the constant value and relation.
+	private static let inverseItem: [NSLayoutConstraint.Attribute] = [.right, .bottom, .trailing, .lastBaseline]
+	#else
+	/// Edges that need the relation to flip arguments. For these we need to inverse the constant value and relation.
+	private static let inverseItem: [NSLayoutConstraint.Attribute] = [.right, .bottom, .trailing, .lastBaseline, .rightMargin, .bottomMargin, .trailingMargin]
+	#endif
+	
+	/// Create and active constraints for provided edges. Constraints will anchor the same edge on both `self` and `other`.
+	/// - Note: Will set `translatesAutoresizingMaskIntoConstraints = false`
+	/// - Parameters:
+	///   - edges: List of constraint attributes, e.g. `[.top, .bottom, .left, .right]`
+	///   - other: Instance to bind to, e.g. `UIView` or `UILayoutGuide`
+	///   - padding: Used as constant value. Multiplier will always be `1.0`. If you need to change the multiplier, use single constraints instead. (Default: `0`)
+	///   - rel: Constraint relation. (Default: `.equal`)
+	/// - Returns: List of created and active constraints
+	@discardableResult func anchor(_ edges: [NSLayoutConstraint.Attribute], to other: Any, padding: CGFloat = 0, if rel: NSLayoutConstraint.Relation = .equal) -> [NSLayoutConstraint] {
+		translatesAutoresizingMaskIntoConstraints = false
+		return edges.map {
+			let (A, B) = Self.inverseItem.contains($0) ? (other, self) : (self, other)
+			return NSLayoutConstraint(item: A, attribute: $0, relatedBy: rel, toItem: B, attribute: $0, multiplier: 1, constant: padding).on()
+		}
+	}
+	
+	/// Sets the priority with which a view resists being made smaller and larger than its intrinsic size.
+	func constrainHuggingCompression(_ axis: ConstraintAxis, _ priotity: ConstraintPriority) {
+		setContentHuggingPriority(priotity, for: axis)
+		setContentCompressionResistancePriority(priotity, for: axis)
+	}
+}
+
+public extension Array where Element: NSLayoutConstraint {
+	/// set `priority` on all elements and return same list
+	@discardableResult static func |(l: Self, r: ConstraintPriority) -> Self {
+		for x in l { x.priority = r }
+		return l
+	}
+	/// set `isActive` on all elements and return `self`
+	@discardableResult func setActive(_ flag: Bool) -> Self {
+		flag ? NSLayoutConstraint.activate(self) : NSLayoutConstraint.deactivate(self)
+		return self
+	}
+}