Neon is built around how user interfaces are naturally and intuitively designed. No more springs and struts. No more whacky visual format language. No more auto layout contraints. We're not robots, so why should we build our UIs like we are?

Neon is currently in beta, but more will be coming very soon, so stay tuned!

Rather than design some arbitrary layout for a demonstration, I figured a good test for the practicality of Neon would be to replicate an existing screen from a major app, one that everyone could recognize. The above screenshot on the left is my profile in the Facebook app, and the screenshot on the right is from the Neon demo project.

Facebook's profile screen was surely built using some form of UITableView or UICollectionView, but for the sake of simple demonstration I built the top-most major components of the profile in a normal UIViewController. After all the customization of the subviews to make them as close to Facebook's design as possible (I tried my best), this is what I came up with for the layout:

let isLandscape : Bool = UIDevice.currentDevice().orientation.isLandscape.boolValue
let bannerHeight : CGFloat = view.height() * 0.43
let avatarHeightMultipler : CGFloat = isLandscape ? 0.75 : 0.43
let avatarSize = bannerHeight * avatarHeightMultipler

searchBar.fillSuperview()
bannerImageView.anchorAndFillEdge(.Top, xPad: 0, yPad: 0, otherSize: bannerHeight)
bannerMaskView.fillSuperview()
avatarImageView.anchorInCorner(.BottomLeft, xPad: 15, yPad: 15, width: avatarSize, height: avatarSize)
nameLabel.alignAndFillWidth(align: .ToTheRightCentered, relativeTo: avatarImageView, padding: 15, height: 120)
cameraButton.anchorInCorner(.BottomRight, xPad: 10, yPad: 7, width: 28, height: 28)
buttonContainerView.alignAndFillWidth(align: .UnderCentered, relativeTo: bannerImageView, padding: 0, height: 62)
buttonContainerView.groupAndFill(group: .Horizontal, views: [postButton, updateInfoButton, activityLogButton, moreButton], padding: 10)
buttonContainerView2.alignAndFillWidth(align: .UnderCentered, relativeTo: buttonContainerView, padding: 0, height: 128)
buttonContainerView2.groupAndFill(group: .Horizontal, views: [aboutView, photosView, friendsView], padding: 10)

Looks pretty good on every device size! Now, keep in mind you'll probably want constants defined for many of these size/padding values, in order to keep the code cleaner and easier to maintain, but I decided to use real numbers for most of the values to make the code less obscure when new people are reading through the demonstration. Now, unlike Facebook's iPhone app the layout built with Neon is dynamic. It is able to handle rotation on all-sized devices with no problem:

###Not bad for 10 lines of code!

Here's an intentionally convoluted example to show how easy it is to build very complex and dynamic layouts with Neon. The following layout was created with only 20 lines of code. That's one line of code per view! While impressive, this layout is horrifying and should never be used in an actual app... ever...

There are a few ways you can anchor views using Neon, and the first and most simple is anchoring a view in the center of its superview:

view1.anchorInCenter(width: size, height: size)

Sometimes you want a view to fill its superview entirely, which couldn't be easier.

view.fillSuperview()

Optionally, if you want a view to fill its superview with padding, you can provide padding instead:

view1.fillSuperview(left: padding, right: padding, top: padding, bottom: padding)

The second anchoring method is anchoring a view in its superview's Corner. As you might have guessed, the four corners are .TopLeft, .TopRight, .BottomLeft, .BottomRight, and coupled with the anchorInCorner() function, you can easily anchor a view in any corner like this:

view1.anchorInCorner(.TopLeft, xPad: padding, yPad: padding, width: size, height: size)
view2.anchorInCorner(.TopRight, xPad: padding, yPad: padding, width: size, height: size)
view3.anchorInCorner(.BottomLeft, xPad: padding, yPad: padding, width: size, height: size)
view4.anchorInCorner(.BottomRight, xPad: padding, yPad: padding, width: size, height: size)

Edge is another pretty obvious one to follow - it specifies on what edge of its superview a view will be anchored to. The four types are .Top, .Left, .Bottom, or .Right, and similar to previous examples, you can use the anchorToEdge() function to anchor a view to an edge:

view1.anchorToEdge(.Top, padding: padding, width: size, height: size)
view2.anchorToEdge(.Left, padding: padding, width: size, height: size)
view3.anchorToEdge(.Bottom, padding: padding, width: size, height: size)
view4.anchorToEdge(.Right, padding: padding, width: size, height: size)

Sometimes, you want to anchor a view against an edge, filling that edge; imagine something like a banner photo for a profile page. Again, this is made as simple as possible using the anchorAndFillEdge() function:

view1.anchorAndFillEdge(.Top, xPad: padding, yPad: padding, otherSize: size)
view2.anchorAndFillEdge(.Bottom, xPad: padding, yPad: padding, otherSize: size)
view3.anchorAndFillEdge(.Left, xPad: padding, yPad: padding, otherSize: size)
view4.anchorAndFillEdge(.Right, xPad: padding, yPad: padding, otherSize: size)

Note that anchorAndFillEdge() accepts a parameter called otherSize. That parameter is used to set the other size that isn't automatically calculated by filling the edge, meaning that if you specify that you want to anchor to and fill the top edge, the width will be automatically calculated, but the height is still unknown, so the value passed in to otherSize will be used to set the height. Subsequently, if you want to anchor to and fill the left edge, the height is automatically calculated and otherSize will be used to set the width of the view.

Now that we've anchored primary views, we can start making our UI more complex by aligning other views relative to other sibling views, using the (you guessed it) Align value. Sibling views are views that share the same superview directly. There are twelve Align types, and they are all pretty self-explanatory - here's an example using all nine with the align() function:

view1.align(.AboveMatchingLeft, relativeTo: anchorView, padding: padding, width: size, height: size)
view2.align(.AboveCentered, relativeTo: anchorView, padding: padding, width: size, height: size)
view3.align(.AboveMatchingRight, relativeTo: anchorView, padding: padding, width: size, height: size)
view4.align(.ToTheRightMatchingTop, relativeTo: anchorView, padding: padding, width: size, height: size)
view5.align(.ToTheRightCentered, relativeTo: anchorView, padding: padding, width: size, height: size)
view6.align(.ToTheRightMatchingBottom, relativeTo: anchorView, padding: padding, width: size, height: size)
view7.align(.UnderMatchingRight, relativeTo: anchorView, padding: padding, width: size, height: size)
view8.align(.UnderCentered, relativeTo: anchorView, padding: padding, width: size, height: size)
view9.align(.UnderMatchingLeft, relativeTo: anchorView, padding: padding, width: size, height: size)
view10.align(.ToTheLeftMatchingBottom, relativeTo: anchorView, padding: padding, width: size, height: size)
view11.align(.ToTheLeftCentered, relativeTo: anchorView, padding: padding, width: size, height: size)
view12.align(.ToTheLeftMatchingTop, relativeTo: anchorView, padding: padding, width: size, height: size)

You don't always know or what to specify the size of a view that you want to layout relative to another, but rather you want to either fill the width, height, or the entire rest of the superview, after aligning with the sibling. Combined with all the different alignment types discussed earlier, we're starting to see how more complex layouts can be built very easily:

view2.alignAndFillWidth(align: .ToTheRightMatchingTop, relativeTo: view1, padding: padding, height: size / 2.0)
view4.alignAndFillHeight(align: .AboveCentered, relativeTo: view3, padding: padding, width: size / 2.0)
view6.alignAndFill(align: .ToTheLeftMatchingTop, relativeTo: view5, padding: padding)

Sometimes you want a view to sit between to other views, filling the space between them. Using alignBetweenHorizontal() and alignBetweenVertical(), doing that is super easy! Choose one of your sibling views you want to align your view relative to and pass that in as your primaryView. We will use the specified align parameter to match that primaryView appropriately, and automatically fill either the horizontal or vertical span between the it and the secondaryView.

view1.alignBetweenHorizontal(align: .ToTheRightMatchingTop, primaryView: anchorViewA, secondaryView: anchorViewB, padding: padding, height: size)
view2.alignBetweenVertical(align: .UnderCentered, primaryView: anchorViewB, secondaryView: anchorViewD, padding: padding, width: size)
view3.alignBetweenHorizontal(align: .ToTheLeftMatchingBottom, primaryView: anchorViewD, secondaryView: anchorViewC, padding: padding, height: size)
view4.alignBetweenVertical(align: .AboveMatchingRight, primaryView: anchorViewC, secondaryView: anchorViewA, padding: padding, width: size)

Another common use-case is the grouping of sibling views, aligned in a row or column. Using what we've already learned about anchoring views in the center, in a corner, or against an edge, we can also do the same with groups of views!

The primary difference with grouping, is that it is done by the parent view, or superview of a group of views. For example, let's let two different views center a group of their subviews in each of the two different Group configurations, .Horizontal and .Vertical:

anchorViewA.groupInCenter(group: .Horizontal, views: [view1, view2, view3], padding: padding, width: size, height: size)
anchorViewB.groupInCenter(group: .Vertical, views: [view4, view5, view6], padding: padding, width: size, height: size)

How about grouping views in the corner?

anchorViewA.groupInCorner(group: .Horizontal, views: [view1, view2, view3], inCorner: .TopLeft, padding: padding, width: size, height: size)
anchorViewB.groupInCorner(group: .Vertical, views: [view4, view5, view6], inCorner: .BottomRight, padding: padding, width: size, height: size)

As you might have expected, you can also group either horizontally and vertically against any edge as well:

anchorViewA.groupAgainstEdge(group: .Horizontal, views: [view1, view2, view3], againstEdge: .Left, padding: padding, width: size, height: size)
anchorViewB.groupAgainstEdge(group: .Vertical, views: [view4, view5, view6], againstEdge: .Bottom, padding: padding, width: size, height: size)

You can also specify that you want a group of subviews to fill their superview, either horizontally or vertically:

anchorViewA.groupAndFill(group: .Horizontal, views: [view1, view2, view3], padding: padding)
anchorViewB.groupAndFill(group: .Vertical, views: [view4, view5, view6], padding: padding)

The source is made available under the MIT license. See LICENSE.txt for details.