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Driftwood is a DSL to make Auto Layout easy on iOS, tvOS and macOS.

Requirements

• iOS 8.0+/macOS 10.11+/tvOS 9.0+
• Swift 4.2+

Installation

Driftwood is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'Driftwood'

Usage

Driftwood is easy to use, you can make full constraints satisfication in just a few code.

Let's say we want to layout a box that is constrained to it’s superview’s edges with 0pts of padding.

let box = UIView()
superview.addSubview(box)
box.dw.make().left(0).top(0).right(0).bottom(0)

Or another way:

let box = UIView()
superview.addSubview(box)
box.dw.make().edge(insets: .zero)

Attribute

All NSLayoutConstraint.Attribute cases are available in Driftwood.

Let's say view1 is at the bottom of view2, offset with 10pts.

view1.dw.make().top(10, to: view2.dw.bottom)

Full list of NSLayoutConstraint.Attribute:

Relation & Multiply & Priority

• relation: default is .equal
• multiply: default is 1
• priority: default is .required

dw.make()

As you see above, you can use dw.make() to make full constraints easily.

dw.update()

You can use dw.update() to updating constant and priority value of a constraint.

view1.dw.update().top(200)

view2.dw.update().left(100, priority: .required)

dw.remake()

dw.remake() is similar to dw.make(), but will first remove all existing constraints installed by Driftwood.

view.dw.remake().left(20).top(30).width(20).height(10)

dw.remove()

You can use dw.remove() to removing any existing constraints installed by Driftwood.

view.dw.remove().left().top()

dw.removeAll()

Sometimes, you may just want to remove all constraints installed before. You can use dw.removeAll() to removing all existing constraints installed by Driftwood.

view.dw.removeAll()

LayoutGuide

Driftwood can works with LayoutGuide easily.

let guide = UILayoutGuide()
superview.addLayoutGuide(guide)
guide.dw.make().left(10).top(10).height(10).width(10)

let box = UIView()
superview.addSubview(box)
box.dw.make().top(0, to: guide.dw.bottom).left(0).right(0).height(10)

Cache

All constraints installed by Driftwood will be cached for future reuse.

Debug

You can labeled with a name to any View or LayoutGuide for debug.

view.dw.make(labeled: "MyView").left(0).left(0)

It will be logs like this:

<Driftwood.@ViewController#23.[make left].(UIView`MyView`:0x00007fc636525da0)>: Duplicated constraint.

If resulting Unable to simultaneously satisfy constraints, it will be logs like this for each constraint installed by Driftwood:

<Driftwood.@ViewController#23.[make left].(UIView`MyView`:0x00007fc636525da0.left == UIView:0x00007fc636525111.right)>

NOTE: In release, Driftwood will not log debug info.

Demo

You can download this repo to see more usage.

Author

wlgemini, wangluguang@live.com

License

Driftwood is available under the MIT license. See the LICENSE file for more info.