【Swift】便利な関数

備忘録

下記の動画より学んだ便利な関数です。

レイアウトやサイズの設定

anchor

extension UIView {

    func anchor(
        top: NSLayoutYAxisAnchor? = nil,
        bottom: NSLayoutYAxisAnchor? = nil,
        left: NSLayoutXAxisAnchor? = nil,
        right: NSLayoutXAxisAnchor? = nil,
        centerY: NSLayoutYAxisAnchor? = nil,
        centerX: NSLayoutXAxisAnchor? = nil,
        width: CGFloat? = nil,
        height: CGFloat? = nil,
        topPadding: CGFloat = 0,
        bottomPadding: CGFloat = 0,
        leftPadding: CGFloat = 0,
        rightPadding: CGFloat = 0) {
        
        self.translatesAutoresizingMaskIntoConstraints = false
        
        if let top = top {
            self.topAnchor.constraint(equalTo: top, constant: topPadding).isActive = true
        }
        
        if let bottom = bottom {
            self.bottomAnchor.constraint(equalTo: bottom, constant: -bottomPadding).isActive = true
        }
        
        if let left = left {
            self.leftAnchor.constraint(equalTo: left, constant: leftPadding).isActive = true
        }
        
        if let right = right {
            self.rightAnchor.constraint(equalTo: right, constant: -rightPadding).isActive = true
        }
        
        if let centerY = centerY {
            self.centerYAnchor.constraint(equalTo: centerY).isActive = true
        }
        
        if let centerX = centerX {
            self.centerXAnchor.constraint(equalTo: centerX).isActive = true
        }
        
        if let width = width {
            self.widthAnchor.constraint(equalToConstant: width).isActive = true
        }
        
        if let height = height {
            self.heightAnchor.constraint(equalToConstant: height).isActive = true
        }
        
    }
    
}

画像のリサイズ

resize

extension UIImage {

    func resize(size _size: CGSize) -> UIImage? {
        let widthRatio = _size.width / size.width
        let heightRatio = _size.height / size.height
        let ratio = widthRatio < heightRatio ? widthRatio : heightRatio
        let resizeSize = CGSize(width: size.width * ratio, height: size.height * ratio)
        
        UIGraphicsBeginImageContextWithOptions(resizeSize,false, 0.0)
        draw(in: CGRect(origin: .zero, size: resizeSize))
        let resizedImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        return resizedImage
    }
}

色の設定

rgb

extension UIColor {
    
    static func rgb(red:CGFloat,green:CGFloat,blue:CGFloat) -> UIColor{
        return .init(red: red/255, green: green/255, blue: blue/255, alpha: 1)
    }
}