Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/puffinsupply/Restraint
Minimal Auto Layout in Swift
https://github.com/puffinsupply/Restraint
Last synced: 8 days ago
JSON representation
Minimal Auto Layout in Swift
- Host: GitHub
- URL: https://github.com/puffinsupply/Restraint
- Owner: puffinsupply
- Created: 2015-04-29T23:46:00.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2020-11-26T06:51:13.000Z (about 4 years ago)
- Last Synced: 2024-08-14T14:06:29.329Z (4 months ago)
- Language: Swift
- Size: 112 KB
- Stars: 79
- Watchers: 7
- Forks: 11
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
- awesome-ios - Restraint - Minimal Auto Layout in Swift. (Layout / Other Hardware)
- awesome-ios-star - Restraint - Minimal Auto Layout in Swift. (Layout / Other Hardware)
- awesome-swift-cn - Restraint - Minimal Auto Layout in Swift. (Libs / Layout)
README
# Restraint
Restraint is a very very small library to help make your use of `NSLayoutConstraint` in Swift more legible & declarative.
- Like programmatic views?
- Like the benefits of using pure AutoLayout?
- Like clear and minimal interfaces?
- Dislike Visual Format Language and "stringly" typing?
- Dislike the verbosity of `NSLayoutConstraint`?
- Dislike heavy dependencies?
- Practice `Restraint`!
## Features
- [x] As simple as possible
- [x] Easy to maintain
- [x] Easy to replace
- [x] Easy to circumvent
- [x] Not too clever
- [x] Sane defaults
- [x] Automatic handling of `setTranslatesAutoresizingMaskIntoConstraints`
## Basic Example
Let's set the height & width of an `imageView` to `200` points and center in the current `UIView`. Here's how we would do that with `NSLayoutConstraint`:
```swift
let imageViewWidthConstraint = NSLayoutConstraint(
item: imageView,
attribute: .Height,
relatedBy: .Equal,
toItem: nil,
attribute: .NotAnAttribute,
multiplier: 1.0,
constant: 200
)
let imageViewHeightConstraint = NSLayoutConstraint(
item: imageView,
attribute: .Width,
relatedBy: .Equal,
toItem: nil,
attribute: .NotAnAttribute,
multiplier: 1.0,
constant: 200
)
imageView.addConstraints([imageViewWidthConstraint, imageViewHeightConstraint])
let imageViewHorizontalConstraint = NSLayoutConstraint(
item: imageView,
attribute: .CenterX,
relatedBy: .Equal,
toItem: self,
attribute: .CenterX,
multiplier: 1.0,
constant: 0
)
let imageViewVerticalConstraint = NSLayoutConstraint(
item: imageView,
attribute: .CenterY,
relatedBy: .Equal,
toItem: self,
attribute: .CenterY,
multiplier: 1.0,
constant: 0
)
addConstraints([imageViewHorizontalConstraint, imageViewVerticalConstraint])
```
### :fearful:
And of course, this depends upon your particular formatting conventions. You know how quickly this gets out of hand.
Here's how to apply these same constraints with `Restraint`:
```swift
Restraint(imageView, .Width, .Equal, 200).addToView(imageView)
Restraint(imageView, .Height, .Equal, 200).addToView(imageView)
Restraint(imageView, .CenterX, .Equal, self, .CenterX).addToView(self)
Restraint(imageView, .CenterY, .Equal, self, .CenterY).addToView(self)
```
### :massage:
## Detailed Example
For this view, we'd like to:
- Center the `imageView` (which is of a fixed size) vertically and horizontally in the containing view.
- Center `topLabel` (which is of a variable size) vertically between the top of `imageView` and the top of the containing view.
- Center `topLabel` horizontally in the containing view.
- Center `bottomLabel` (which is of a variable size) vertically between the bottom of `imageView` and the bottom of the containing view.
- Set the width of `bottomLabel` to the width of the containing view less its layout margins.
Here are those rules expressed with `Restraint`:
```swift
// Image View Constraints
Restraint(imageView, .Width, .Equal, imageViewSize).addToView(self)
Restraint(imageView, .Height, .Equal, imageViewSize).addToView(self)
Restraint(imageView, .CenterX, .Equal, self, .CenterX).addToView(self)
Restraint(imageView, .CenterY, .Equal, self, .CenterY).addToView(self)
// Top Label Constraints
Restraint(topLabel, .CenterX, .Equal, imageView, .CenterX).addToView(self)
Restraint(topLabel, .CenterY, .Equal, imageView, .Top, 0.5, 0).addToView(self)
// Bottom Label Constraints
Restraint(bottomLabel, .Left, .Equal, self, .LeftMargin).addToView(self)
Restraint(bottomLabel, .Right, .Equal, self, .RightMargin).addToView(self)
Restraint(bottomLabel, .CenterY, .Equal, self, .CenterY, 1.5, (200 / 4)).addToView(self)
```
You can see this in action in [Example/View.swift](Example/Example/View.swift)
## How It Works
Each `Restraint` simply creates the appropriate `NSLayoutConstraint`, and the call to `addToView` disables `translatesAutoresizingMaskIntoConstraints` on the left view in the constraint and adds that constraint to the target view.
Optionally, you can call `Restraint().constraint()` to get an instance of `NSLayoutConstraint` and add your constraint with `UIView#addConstraint` or `#addConstraints` later. For example:
```swift
let heightConstraint = Restraint(imageView, .Height, .Equal, 200).constraint()
imageView.addConstraint(heightConstraint)
```
In this case you'll need to handle disabling `translatesAutoresizingMaskIntoConstraints` yourself.
## Installation
### Carthage
Add the following to your project's `Cartfile`:
```swift
github "puffinsupply/Restraint" >= 1.0
```
### Manual
Simply add [Restraint.swift](Restraint/Restraint.swift) to your project.
## Contributors
- [Adam Michela](https://github.com/soopa/)
- [Michael Bachand](https://github.com/bachand/)
- [Drew Yeaton](https://github.com/drewyeaton/)
## License
- [MIT](http://thi.mit-license.org/)