swift3.0, 常用extensions

1

import Foundation
import UIKit

extension UIImage {
  /// Returns a image that fills in newSize
  func resizedImage(newSize: CGSize) -> UIImage {
    // Guard newSize is different
    guard self.size != newSize else { return self }
    
    UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0);
    self.draw(in: CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height))
    let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()
    return newImage
  }
  
  /// Returns a resized image that fits in rectSize, keeping it's aspect ratio
  /// Note that the new image size is not rectSize, but within it.
  func resizedImageWithinRect(rectSize: CGSize) -> UIImage {
    let widthFactor = size.width / rectSize.width
    let heightFactor = size.height / rectSize.height
    
    var resizeFactor = widthFactor
    if size.height > size.width {
      resizeFactor = heightFactor
    }
    
    let newSize = CGSize(width: size.width/resizeFactor, height: size.height/resizeFactor)
    let resized = resizedImage(newSize: newSize)
    return resized
  }
}

2

import Foundation

extension Array {
  mutating func moveToTop(at index: Int) {
    rearrange(from: index, to: 0)
  }
  mutating func rearrange(from index1: Int, to index2: Int) {
    if index1 >= self.count || index2 >= self.count {
      return
    }
    insert(remove(at: index1), at: index2)
  }
}

3

import Foundation
import UIKit

// MARK: - Convenience methods for UIView
public extension UIView {
    convenience init(color: UIColor) {
        self.init()
        backgroundColor = color
    }
    
    func clipsToBoundsAndRasterize() {
        clipsToBounds = true
        layer.shouldRasterize = true
        layer.rasterizationScale = UIScreen.main.scale
    }
    
    func addBottomBorderWithColor(color: UIColor, width: CGFloat) {
        let view = UIView()
        view.backgroundColor = color
        self.addSubview(view)
        view.snp.makeConstraints { (make) in
            make.width.equalToSuperview()
            make.height.equalTo(width)
            make.bottom.equalToSuperview()
            make.left.equalToSuperview()
        }
    }
    
    func with(color: UIColor) -> Self {
        backgroundColor = color
        return self
    }
    
    func with(radius: CGFloat) -> Self {
        layer.cornerRadius = radius
        return self
    }
    
    // add corner to a corner
    // if using autolayout call it in layoutSubviews
    // view.roundCorners([.topLeft, .bottomRight], radius: 10)
    func roundCorners(_ corners: UIRectCorner, radius: CGFloat) {
        let path = UIBezierPath(roundedRect: bounds,
                                byRoundingCorners: corners,
                                cornerRadii: CGSize(width: radius, height: radius))
        let mask = CAShapeLayer()
        mask.path = path.cgPath
        layer.mask = mask
    }

}