github "kzms/Crew"

view <<= view1 ~ .Height == view1 ~ .Width

// same as:
// view.addConstraint(NSLayoutConstraint(item: view1, attribute: .Height, relatedBy: .Equal, toItem: view1, attribute: .Width, multiplier: 1, constant: 0))

view <<= view1 ~ .Height == 30

// same as:
// view.addConstraint(NSLayoutConstraint(item: view1, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: 30))

view <<= view1 == CGSize(width: 100, height: 200)

// same as:
// view <<= view1 ~ .Width == 100
// view <<= view1 ~ .Height == 200

view <<= (view1, view2) == .Top

// same as
// view <<= view1 ~ .Top == view2 ~ .Top

view <<= (view1, view2) == [.CenterX, .CenterY]

// same as
// view <<= view1 ~ .CenterX == view2 ~ .CenterX
// view <<= view1 ~ .CenterY == view2 ~ .CenterY

view <<= view2 ~ .Top == view1 ~ .Bottom
view <<= view3 ~ .Top == view2 ~ .Bottom + 10

// same as:
// view.addConstraint(NSLayoutConstraint(item: view2, attribute: .Bottom, relatedBy: .Equal, toItem: view1, attribute: .Top, multiplier: 1, constant: 0))
// view.addConstraint(NSLayoutConstraint(item: view3, attribute: .Bottom, relatedBy: .Equal, toItem: view2, attribute: .Top, multiplier: 1, constant: 10))
//
// or:
// view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:[view1][view2]-(10)-[view3]", options: 0, metrics: nil, views: ["view1": view1, "view2": view2, "view3": view3]))

view <<= view == view1 + UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)

// same as:
// view.addConstraint(NSLayoutConstraint(item: view, attribute: .Top, relatedBy: .Equal, toItem: view1, attribute: .Top, multiplier: 1, constant: -10))
// view.addConstraint(NSLayoutConstraint(item: view, attribute: .Left, relatedBy: .Equal, toItem: view1, attribute: .Left, multiplier: 1, constant: -10))
// view.addConstraint(NSLayoutConstraint(item: view, attribute: .Bottom, relatedBy: .Equal, toItem: view1, attribute: .Bottom, multiplier: 1, constant: 10))
// view.addConstraint(NSLayoutConstraint(item: view, attribute: .Right, relatedBy: .Equal, toItem: view1, attribute: .Right, multiplier: 1, constant: 10))

view <<= view == view1 + UIEdgeInsets(top: .NaN, left: 10, bottom: .NaN, right: 10)

// same as:
// view.addConstraint(NSLayoutConstraint(item: view, attribute: .Left, relatedBy: .Equal, toItem: view1, attribute: .Left, multiplier: 1, constant: -10))
// view.addConstraint(NSLayoutConstraint(item: view, attribute: .Right, relatedBy: .Equal, toItem: view1, attribute: .Right, multiplier: 1, constant: 10))

view <<= view1 ~ .CenterX == view ~ .CenterX
view <<= view1 ~ .CenterY == view ~ .CenterY

// same as:
// view.addConstraint(NSLayoutConstraint(item: view1, attribute: .CenterX, relatedBy: .Equal, toItem: view, attribute: .CenterX, multiplier: 1, constant: 0))
// view.addConstraint(NSLayoutConstraint(item: view1, attribute: .CenterY, relatedBy: .Equal, toItem: view, attribute: .CenterY, multiplier: 1, constant: 0))

view1 ~ .Top == view2 ~ .Top ! 500
view == CGSize(width: 100, height: 200) ! 250