Fix CGAffineTransform on non-Darwin platform

Sources/OpenCoreGraphics/CGAffineTransform.swift

@@ -52,17 +52,15 @@ extension CGAffineTransform {
     }
 
     public func translatedBy(x tx: CGFloat, y ty: CGFloat) -> CGAffineTransform {
-        let t = CGAffineTransform(a: 1, b: 0, c: 0, d: 1, tx: Double(tx), ty: Double(ty))
-        return concatenating(t)
+        CGAffineTransform(a: 1, b: 0, c: 0, d: 1, tx: Double(tx), ty: Double(ty)).concatenating(self)
     }
 
     public func scaledBy(x sx: CGFloat, y sy: CGFloat) -> CGAffineTransform {
-        let s = CGAffineTransform(a: Double(sx), b: 0, c: 0, d: Double(sy), tx: 0, ty: 0)
-        return concatenating(s)
+        CGAffineTransform(a: Double(sx), b: 0, c: 0, d: Double(sy), tx: 0, ty: 0).concatenating(self)
     }
 
     public func rotated(by angle: CGFloat) -> CGAffineTransform {
-        return concatenating(CGAffineTransform(rotationAngle: angle))
+        CGAffineTransform(rotationAngle: angle).concatenating(self)
     }
 
     public func inverted() -> CGAffineTransform {

Tests/OpenCoreGraphicsShimsTests/CGAffineTransformTests.swift

@@ -5,6 +5,11 @@
 import Testing
 import OpenCoreGraphicsShims
 import Numerics
+#if OPENCOREGRAPHICS_COREGRAPHICS
+import struct CoreGraphics.CGAffineTransform
+#else
+import struct OpenCoreGraphics.CGAffineTransform
+#endif
 
 @Suite
 struct CGAffineTransformTests {
@@ -92,4 +97,46 @@ struct CGAffineTransformTests {
         #expect(inv.tx.isApproximatelyEqual(to: singular.tx))
         #expect(inv.ty.isApproximatelyEqual(to: singular.ty))
     }
+
+    // MARK: - TranslateBy
+
+    @Test
+    func translatedBy() {
+        let t1 = CGAffineTransform(a: 1, b: 2, c: 3, d: 4, tx: 5, ty: 6)
+        let t2 = t1.translatedBy(x: 7, y: 8)
+        #expect(t2.a.isApproximatelyEqual(to: 1.0))
+        #expect(t2.b.isApproximatelyEqual(to: 2.0))
+        #expect(t2.c.isApproximatelyEqual(to: 3.0))
+        #expect(t2.d.isApproximatelyEqual(to: 4.0))
+        #expect(t2.tx.isApproximatelyEqual(to: 36.0))
+        #expect(t2.ty.isApproximatelyEqual(to: 52.0))
+    }
+
+    // MARK: - ScaledBy
+
+    @Test
+    func scaledBy() {
+        let t1 = CGAffineTransform(a: 1, b: 2, c: 3, d: 4, tx: 5, ty: 6)
+        let t2 = t1.scaledBy(x: 7, y: 8)
+        #expect(t2.a.isApproximatelyEqual(to: 7.0))
+        #expect(t2.b.isApproximatelyEqual(to: 14.0))
+        #expect(t2.c.isApproximatelyEqual(to: 24.0))
+        #expect(t2.d.isApproximatelyEqual(to: 32.0))
+        #expect(t2.tx.isApproximatelyEqual(to: 5.0))
+        #expect(t2.ty.isApproximatelyEqual(to: 6.0))
+    }
+
+    // MARK: - Rotated
+
+    @Test
+    func rotated() {
+        let t1 = CGAffineTransform(a: 1, b: 2, c: 3, d: 4, tx: 5, ty: 6)
+        let t2 = t1.rotated(by: .pi / 2)
+        #expect(t2.a.isApproximatelyEqual(to: 3.0))
+        #expect(t2.b.isApproximatelyEqual(to: 4.0))
+        #expect(t2.c.isApproximatelyEqual(to: -1.0))
+        #expect(t2.d.isApproximatelyEqual(to: -2.0))
+        #expect(t2.tx.isApproximatelyEqual(to: 5.0))
+        #expect(t2.ty.isApproximatelyEqual(to: 6.0))
+    }
 }