Move the origin of a CGRect to fit inside a parent rect by capping its edges — eg make sure a child rect does not get drawn out of bounds

MoveRectOrigin.swift

extension CGRect {
  mutating func moveOriginToFitIn(_ rect: CGRect) {
    origin = .init(
      x: min(
        max(rect.minX, minX),
        rect.maxX - width
      ),
      y: min(
        max(rect.minY, minY),
        rect.maxY - height
      )
    )
  }
}