Swift extension #2 Initializers의 확장

Initializers의 확장

1. struct Size {
2. var width = 0.0, height = 0.0
3. }
4. struct Point {
5. var x = 0.0, y = 0.0
6. }
7. struct Rect {
8. var origin = Point()
9. var size = Size()
10. }

1. let defaultRect = Rect()
2. let memberwiseRect = Rect(origin: Point(x: 2.0, y: 2.0),
3. size: Size(width: 5.0, height: 5.0))

1. extension Rect {
2. init(center: Point, size: Size) {
3. let originX = center.x - (size.width / 2)
4. let originY = center.y - (size.height / 2)
5. self.init(origin: Point(x: originX, y: originY), size: size)
6. }
7. }

1. let centerRect = Rect(center: Point(x: 4.0, y: 4.0),
2. size: Size(width: 3.0, height: 3.0))
3. // centerRect's origin is (2.5, 2.5) and its size is (3.0, 3.0)