Yalta is an intuitive and powerful Auto Layout library. Designed to be simple and safe, Yalta is perfect for both new and seasoned developers.

The entire library fits in just two files (core + extensions) with less than 250 lines of code which you can just drag-n-drop into your app.

• Quick Overview
• Full Guide
• Installation Guide

Yalta strives for clarity and simplicity by following Swift API Design Guidelines. Although most of the APIs are compact, it is a non-goal to enable the most concise syntax possible. Instead, Yalta has a fluent API that makes use sites form grammatical English phrases - that's what makes Swift code really stand out.

In Yalta, you start by selecting an anchor or a collection of anchors of a view (or a layout guide). Then use anchor's methods to create constraints.

Anchors represent layout attributes of a view including edges, dimensions, axis and baselines.

The best way to access anchors is by using a special addSubview(_:constraints:) method (supports up to 4 views). Here are some examples of what you can do using anchors:

view.addSubview(subview) {
    $0.edges.pinToSuperview() // Pins the edges to fill the superview
    $0.edges.pinToSuperview(insets: Insets(10)) // With insets
    $0.edges.pinToSuperviewMargins() // Or margins

    $0.edges(.left, .right).pinToSuperview() // Fill along horizontal axis
    $0.centerY.alignWithSuperview() // Center along vertical axis
}

With addSubview(_:constraints:) method you define a view hierarchy and layout views at the same time. It encourages splitting layout code into logical blocks and prevents some programmer errors (e.g. trying to add constraints to views not in view hierarchy).

Each anchor and collection of anchors have methods which make sense for that particular kind of anchor:

view.addSubview(title, subtitle) { title, subtitle in
    subtitle.top.align(with: title.bottom + 10)

    title.centerX.alignWithSuperview()

    title.width.set(100)
    subtitle.width.match(title.width + 20)

    // You can change a priority of constraints inside a group:
    subtitle.bottom.pinToSuperview().priority = UILayoutPriority(999)
}

All anchors are also accessible via .al proxy:

title.al.top.pinToSuperview()

Yalta has full test coverage. If you'd like to learn about which constraints (NSLayoutConstraint) Yalta creates each time you call one of its methods, test cases are a great place to start.

Yalta is for someone who:

• Prefers fluent APIs that follow Swift API Design Guidelines
• Doesn't want to depend on big, complex libraries
• Avoids operator overloads and prefers fast compile times
• Likes NSLayoutAnchor but wished it had simpler, more fluent API which didn't require manually activating constraints

Yalta is a beautiful port city on the Black Sea, and a great name for yet another layout tool with anchors.