Add center anchor

Author: ale-zai

…rumentsUI/EdgesAnchor/AnchorsTrait.swift …InstrumentsUI/Anchors/AnchorsTrait.swiftSources/InstrumentsUI/EdgesAnchor/AnchorsTrait.swift renamed to Sources/InstrumentsUI/Anchors/AnchorsTrait.swift Sources/InstrumentsUI/EdgesAnchor/AnchorsTrait.swift renamed to Sources/InstrumentsUI/Anchors/AnchorsTrait.swift

@@ -33,11 +33,21 @@ public protocol AnchorsTrait {
 
    var trailingAnchor: NSLayoutXAxisAnchor { get }
 
+   var centerXAnchor: NSLayoutXAxisAnchor { get }
+
+   var centerYAnchor: NSLayoutYAxisAnchor { get }
+
    var edgesAnchor: EdgesAnchor { get }
+
+   var centerAnchor: CenterAnchor { get }
 }
 
 extension AnchorsTrait {
    public var edgesAnchor: EdgesAnchor {
       EdgesAnchor(anchorsTrait: self)
    }
+
+   public var centerAnchor: CenterAnchor {
+      CenterAnchor(anchorsTrait: self)
+   }
 }

Sources/InstrumentsUI/Anchors/CenterAnchor.swift

@@ -0,0 +1,50 @@
+//
+//  CenterAnchor.swift
+//
+//  Copyright © 2024 Aleksei Zaikin.
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+//
+
+import UIKit
+
+public struct CenterAnchor {
+   private let anchorsTrait: AnchorsTrait
+
+   // MARK: - Init
+
+   init(anchorsTrait: AnchorsTrait) {
+      self.anchorsTrait = anchorsTrait
+   }
+
+   // MARK: - Constraints
+
+   public func constraints(equalTo anchor: CenterAnchor, offset: CGPoint = .zero) -> [NSLayoutConstraint] {
+      var constraints: [NSLayoutConstraint] = []
+      constraints.append(anchorsTrait.centerXAnchor.constraint(
+         equalTo: anchor.anchorsTrait.centerXAnchor,
+         constant: offset.x
+      ))
+      constraints.append(anchorsTrait.centerYAnchor.constraint(
+         equalTo: anchor.anchorsTrait.centerYAnchor,
+         constant: offset.y
+      ))
+      return constraints
+   }
+}