Add HSV conversion

Sources/LibMakeColors/Model/Color+HSV.swift

@@ -0,0 +1,36 @@
+extension Color {
+    init(hue: Int, saturation: UInt8, value: UInt8, alpha: UInt8 = 0xFF) {
+        let degrees = abs(hue % 360)
+
+        let s = Double(saturation) / 0xFF
+        let v = Double(value) / 0xFF
+        let C = s * v
+        let X = C * (1 - abs((Double(degrees) / 60).truncatingRemainder(dividingBy: 2) - 1))
+        let m = v - C
+
+        let result: (r: Double, g: Double, b: Double)
+        switch degrees {
+        case 0..<60:
+            result = (C, X, 0)
+        case 60..<120:
+            result = (X, C, 0)
+        case 120..<180:
+            result = (0, C, X)
+        case 180..<240:
+            result = (0, X, C)
+        case 240..<300:
+            result = (X, 0, C)
+        case 300..<360:
+            result = (C, 0, X)
+        default:
+            fatalError("Degrees out of range")
+        }
+
+        self.init(
+            red: UInt8(((result.r + m) * 0xFF).rounded()),
+            green: UInt8(((result.g + m) * 0xFF).rounded()),
+            blue: UInt8(((result.b + m) * 0xFF).rounded()),
+            alpha: alpha
+        )
+    }
+}

Tests/MakeColorsTests/ColorHSVTest.swift

@@ -0,0 +1,39 @@
+@testable import LibMakeColors
+import XCTest
+
+final class ColorHSVTest: XCTestCase {
+    func testHSV0Degrees() {
+        let color = Color(hue: 0, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0xFF, green: 0, blue: 0))
+    }
+
+    func testHSV60Degrees() {
+        let color = Color(hue: 60, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0xFF, green: 0xFF, blue: 0))
+    }
+
+    func testHSV120Degrees() {
+        let color = Color(hue: 120, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0, green: 0xFF, blue: 0))
+    }
+
+    func testHSV180Degrees() {
+        let color = Color(hue: 180, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0, green: 0xFF, blue: 0xFF))
+    }
+
+    func testHSV240Degrees() {
+        let color = Color(hue: 240, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0, green: 0, blue: 0xFF))
+    }
+
+    func testHSV300Degrees() {
+        let color = Color(hue: 300, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0xFF, green: 0, blue: 0xFF))
+    }
+
+    func testHSV360Degrees() {
+        let color = Color(hue: 360, saturation: 0xFF, value: 0xFF)
+        XCTAssertEqual(color, Color(red: 0xFF, green: 0, blue: 0))
+    }
+}