<Description> : Implementing CGFloat shortest angle distance in radians.

<Type> : feature.

EZSwiftExtensionsTests/CGFloatTests.swift

@@ -66,4 +66,34 @@ class CGFloatTests: XCTestCase {
         XCTAssertGreaterThanOrEqual(randomClosedCGFloat, 0.0)
         XCTAssertLessThanOrEqual(randomClosedCGFloat, 10.0)
     }
+    
+    func testShortestAngleBetweenInRadiansSanityTest() {
+        let firstAngle = CGFloat(0)
+        let secondAngle = CGFloat(1)
+        
+        let shortestAngle = CGFloat.shortestAngleInRadians(from: firstAngle, to: secondAngle)
+        XCTAssertNotNil(shortestAngle)
+        
+        XCTAssertEqual(shortestAngle, secondAngle - firstAngle)
+    }
+    
+    func testShortestAngleFullCirclePi() {
+        let firstAngle = CGFloat(0)
+        let fullCircleAngle = CGFloat(2 * Double.pi)
+        
+        let shortestAngle = CGFloat.shortestAngleInRadians(from: firstAngle, to: fullCircleAngle)
+        XCTAssertNotNil(shortestAngle)
+        
+        XCTAssertEqual(shortestAngle, 0)
+    }
+    
+    func testShortestAngleThreeFourthsCirclePi() {
+        let firstAngle = CGFloat(0)
+        let threeFourthsCircleAngle = CGFloat(1.5 * Double.pi)
+        
+        let shortestAngle = CGFloat.shortestAngleInRadians(from: firstAngle, to: threeFourthsCircleAngle)
+        XCTAssertNotNil(shortestAngle)
+        
+        XCTAssertEqual(shortestAngle, -0.5 * .pi)
+    }
 }

Sources/CGFloatExtensions.swift

@@ -62,4 +62,22 @@ extension CGFloat {
     public static func random(within: ClosedRange<CGFloat>) -> CGFloat {
         return CGFloat.random() * (within.upperBound - within.lowerBound) + within.lowerBound
     }
+    
+    /**
+      EZSE :Returns the shortest angle between two angles. The result is always between
+      -π and π.
+     
+      Inspired from : https://github.com/raywenderlich/SKTUtils/blob/master/SKTUtils/CGFloat%2BExtensions.swift
+     */
+    public static func shortestAngleInRadians(from first: CGFloat, to second: CGFloat) -> CGFloat {
+        let twoPi = CGFloat(.pi * 2.0)
+        var angle = (second - first).truncatingRemainder(dividingBy: twoPi)
+        if (angle >= .pi) {
+            angle = angle - twoPi
+        }
+        if (angle <= -.pi) {
+            angle = angle + twoPi
+        }
+        return angle
+    }
 }