# EZAnchor  [中文介绍](https://github.com/alexliubj/EZAnchor/blob/master/🇨🇳.md)
An easier way to code Autolayout

![Image of EZAnchor](https://raw.githubusercontent.com/alexliubj/EZAnchor/master/Logo.png)

[![Language: Swift 4](https://img.shields.io/badge/language-swift%204-f48041.svg?style=flat)](https://developer.apple.com/swift)
![Platform: iOS 9+](https://img.shields.io/badge/platform-iOS-green.svg?style=flat)
[![CocoaPods compatible](https://img.shields.io/badge/Cocoapods-compatible-4BC51D.svg?style=flat)](https://cocoapods.org/pods/SteviaLayout)
![License: MIT](http://img.shields.io/badge/license-MIT-lightgrey.svg?style=flat)

- [x] Are you annoyed of coding `.active = true` while using Autolayout Anchors over and over again?
- [x] Are you annoyed of coding such long constraint sentence `refreshView.heightAnchor.constraint(equalToConstant: self.refreshViewHeight).isActive = true` over and over again?

Now `EZAnchor` is definitely going to shorten your time of writing Autolayout Anchors by a simple installation.
Let's see how it works:

* Anchor constraint to another anchor
```swift
//Traditional way
viewA.leadingAnchor.constraint(equalTo: viewB.leadingAnchor).isActive = true

//With EZAnchor
viewA.leading == viewB.leading
```
        
* Anchor constraint to another anchor with constant
```swift
//Traditional way
viewA.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 10).isActive = true

//With EZAnchor
viewA.leading == self.view.leading + 10
```
        
* Anchor constraint to another anchor with negative constant
```swift
//Traditional way
viewA.leadingAnchor.constraint(equalTo: viewB.leadingAnchor, constant: -10).isActive = true

//With EZAnchor
viewA.leading == viewB.leading - 10
```
        
* Anchor lessThanOrEqualTo another anchor
```swift
//Traditional way
viewA.leadingAnchor.constraint(lessThanOrEqualTo: viewB.leadingAnchor).isActive = true

//With EZAnchor
viewA.leading <= viewB.leading
```
        
* Anchor greaterThanOrEqualTo another anchor
```swift
viewA.leadingAnchor.constraint(greaterThanOrEqualTo: viewB.leadingAnchor).isActive = true

//With EZAnchor
viewA.leading >= viewB.leading
```
        
* Anchor lessThanOrEqualTo another anchor with constant
```swift
viewA.leadingAnchor.constraint(lessThanOrEqualTo: viewB.leadingAnchor, constant: 10).isActive = true

//With EZAnchor
viewA.leading <= viewB.leading + 10
```
        
* Anchor greaterThanOrEqualTo another anchor with constant
```swift
//Traditional way
viewA.leadingAnchor.constraint(greaterThanOrEqualTo: viewB.leadingAnchor, constant: 10).isActive = true

//With EZAnchor
viewA.leading >= viewB.leading - 10
```
        
* Anchor equalTo another anchor with constant and multiplier
```swift
//Traditional way
viewA.heightAnchor.constraint(equalTo: viewB.heightAnchor, multiplier: 0.1, constant: -10).isActive = true

//With EZAnchor
viewA.height == viewB.height * 0.1 - 10
```

* Work with Priority
```swift
//With EZAnchor
viewA.leading == (viewB.leading + 0.1) ^ .defaultLow
```

## Installation

### Drag and drop
Directly drag `EZAnchor` and drop into your Xcode project.

### CocoaPods
To integrate EZAnchor into your Xcode project using CocoaPods, specify it in your Podfile:
```
target 'MyApp' do
  pod 'EZAnchor'
end
```

### Carthage
To integrate EZAnchor into your Xcode project using Carthage, specify it in your Cartfile:
`coming soon`

Run carthage update to build the framework and drag the built EZAnchor.framework into your Xcode project.

## Demo

You can easily implement the following layout with very simple and clean code:
```swift
//set viewA's layout constraints
let viewA = UIView()
viewA.backgroundColor = UIColor.red
view.addEZSubview(viewA)
        
viewA.leading == view.leading + 5
viewA.trailing == view.trailing - 5
viewA.top == view.top + 15
viewA.centerX == view.centerX
viewA.height == view.height/2
        
//set viewB's layout constraints
let viewB = UIView()
viewB.backgroundColor = UIColor.yellow
view.addEZSubview(viewB)
        
viewB.top == viewA.bottom + 5
viewB.leading == viewA.leading
viewB.bottom == view.bottom - 5
viewB.trailing == view.centerX - 5

//set viewC's layout constraints        
let viewC = UIView()
viewC.backgroundColor = UIColor.green
view.addEZSubview(viewC)
        
viewC.top == viewB.top
viewC.bottom == viewB.bottom
viewC.leading == view.centerX + 5
viewC.trailing == viewA.trailing
        
```
![Image of DemoScreenshot](https://raw.githubusercontent.com/alexliubj/EZAnchor/master/demo.png)

## Chaining function

### Chaining way to code Autolayout with EZAnchor

```swift

viewA.setLeading(view.leading + 5)
     .setTrailing(view.trailing - 5)
     .setTop(view.top + 15)
     .setCenterX(view.centerX)
     .setHeight(view.height/2)


viewB.setTop(viewA.bottom + 5)
     .setLeading(viewA.leading)
     .setBottom(view.bottom - 5)
     .setTrailing(view.centerX - 5)

viewC.setTop(viewB.top)
     .setBottom(viewB.bottom)
     .setLeading(view.centerX + 5)
     .setTrailing(viewA.trailing)

```

## Limitations

1. Better to have some basic concept of anchors, familiar with coding anchors programmatically. If not please learn from this link : [Programmatically Creating Constraints!](https://developer.apple.com/library/archive/documentation/UserExperience/Conceptual/AutolayoutPG/ProgrammaticallyCreatingConstraints.html)

2. Avoid defining custom `UIControl` or view has same name with `height` or `width`, there may have conflict with `EZAnchor` library

## Others
##### [WTF Autolayout](https://www.wtfautolayout.com) will help you debug autolayout complaints.
##### Logo is generated with [Shopify logo maker](https://hatchful.shopify.com/)
##### Inspired by: [PureLayout](https://github.com/PureLayout/PureLayout) [Stevia](https://github.com/freshOS/Stevia) [layout](https://github.com/nicklockwood/layout) 

## Todo
- [ ] Unit tests
- [ ] UI Tests
- [ ] CI
- [ ] Fastlane

## License

This code and tool is under the MIT License.