Layout+

This library lets you create NSLayoutConstraints on iOS and OSX using an intuitive syntax.

You can write this:

addConstraint(label.layout.width == superview.layout.width / 2 + 20)

Instead of:

addConstraint(NSLayoutConstraint(item: label, attribute: .Width,
  relatedBy: .Equal, toItem: superview, attribute: .Width, multiplier: 0.5,
  constant: 20))

How to Use

Use the layout property on your view to identiny the NSLayoutAttribute you'd like to constrain.

view.layout.height
view.layout.centerX
view.layout.trailing
// etc...

Use == <= and >= to define the NSLayoutRelation in the constraint.

label.layout.width == superview.layout.width
button.layout.height <= label.layout.height
view.layout.top >= label.layout.height

You can modify the constant in the constraint with addition or subtraction.

button.layout.top == label.layout.bottom + 40
button.layout.top - 40 == label.layout.bottom

These equations are reflexive, so the above two lines produce identical NSLayoutConstraints.

Multiplication and division similarly will set the multiplier in the constraint.

button.layout.width == label.layout.width * 2
button.layout.width / 2 == label.layout.width

Both of the above two lines will produce identical constraints.

Operate on all the things! YOLO

20 + 2 * button.layout.height - 40 <= 3 * label.layout.height / 2 + 40 - 20

It's handy to quickly define constraints inline with a call to addConstraint, but you can also easily capture them in a variable.

addConstraint(button.layout.leading == label.layout.trailing + 20)

let buttonLeadingConstraint = button.layout.leading == label.layout.trailing + 20

Installation

Layout+ can be easily installed with Carthage.

Add the origin to your Cartfile:

github "guenin/LayoutPlus"

Download & build the framework:

$ carthage update

Drag LayoutPlus.framework from the Carthage/Build folder into the “Embedded Binaries” section for your application target in XCode.

Add import LayoutPlus to any .swift file you want to use it in, and get started!

License

Layout+ is released under the MIT License.