JKSwiftExtension哼勇，測(cè)試用例在 UIImageExtensionViewController.swift 里面
目錄：
1屉更、基本的擴(kuò)展
2魔吐、UIColor 生成的圖片 和 生成漸變色圖片
3夜牡、圖片的拉伸和縮放
4芳誓、UIImage 壓縮相關(guān)
5、二維碼的處理
6兔簇、gif 加載

一发绢、基本的擴(kuò)展

// MARK:- 一、基本的擴(kuò)展
public extension UIImage {

    // MARK: 1.1垄琐、設(shè)置圖片的圓角
    /// 設(shè)置圖片的圓角
    /// - Parameters:
    ///   - radius: 圓角大小 (默認(rèn):3.0,圖片大小)
    ///   - corners: 切圓角的方式
    ///   - imageSize: 圖片的大小
    /// - Returns: 剪切后的圖片
    func isRoundCorner(radius: CGFloat = 3, byRoundingCorners corners: UIRectCorner = .allCorners, imageSize: CGSize?) -> UIImage? {
        let weakSize = imageSize ?? size
        let rect = CGRect(origin: CGPoint(x: 0, y: 0), size: weakSize)
        // 開(kāi)始圖形上下文
        UIGraphicsBeginImageContextWithOptions(weakSize, false, UIScreen.main.scale)
        guard let contentRef: CGContext = UIGraphicsGetCurrentContext() else {
            // 關(guān)閉上下文
            UIGraphicsEndImageContext();
            return nil
        }
        // 繪制路線
        contentRef.addPath(UIBezierPath(roundedRect: rect,
                                    byRoundingCorners: UIRectCorner.allCorners,
                                    cornerRadii: CGSize(width: radius, height: radius)).cgPath)
        // 裁剪
        contentRef.clip()
        // 將原圖片畫到圖形上下文
        draw(in: rect)
        contentRef.drawPath(using: .fillStroke)
        guard let output = UIGraphicsGetImageFromCurrentImageContext() else {
        // 關(guān)閉上下文
            UIGraphicsEndImageContext();
            return nil
        }
       // 關(guān)閉上下文
        UIGraphicsEndImageContext();
        return output
    }

    // MARK: 1.2边酒、設(shè)置圓形圖片
    /// 設(shè)置圓形圖片
    /// - Returns: 圓形圖片
    func isCircleImage() -> UIImage? {
        return isRoundCorner(radius: (self.size.width < self.size.height ? self.size.width : self.size.height) / 2.0, byRoundingCorners: .allCorners, imageSize: self.size)
    }

    // MARK: 1.3、獲取視頻的第一幀
    /// 獲取視頻的第一幀
    /// - Parameters:
    ///   - videoUrl: 視頻 url
    ///   - maximumSize: 圖片的最大尺寸
    /// - Returns: 視頻的第一幀
    static func getVideoFirstImage(videoUrl: String, maximumSize: CGSize = CGSize(width: 1000, height: 1000), closure: @escaping (UIImage?) -> Void) {
        guard let url = URL(string: videoUrl) else {
            closure(nil)
            return
        }
        DispatchQueue.global().async {
            let opts = [AVURLAssetPreferPreciseDurationAndTimingKey: false]
            let avAsset = AVURLAsset(url: url, options: opts)
            let generator = AVAssetImageGenerator(asset: avAsset)
            generator.appliesPreferredTrackTransform = true
            generator.maximumSize = maximumSize
            var cgImage: CGImage? = nil
            let time = CMTimeMake(value: 0, timescale: 600)
            var actualTime : CMTime = CMTimeMake(value: 0, timescale: 0)
            do {
                try cgImage = generator.copyCGImage(at: time, actualTime: &actualTime)
            } catch {
                DispatchQueue.main.async {
                    closure(nil)
                }
                return
            }
            guard let image = cgImage else {
                DispatchQueue.main.async {
                    closure(nil)
                }
                return
            }
            DispatchQueue.main.async {
                closure(UIImage(cgImage: image))
            }
        }
    }

    // MARK: 1.4狸窘、layer 轉(zhuǎn) image
    /// layer 轉(zhuǎn) image
    /// - Parameters:
    ///   - layer: layer 對(duì)象
    ///   - scale: 縮放比例
    /// - Returns: 返回轉(zhuǎn)化后的 image
    static func image(from layer: CALayer, scale: CGFloat = 0.0) -> UIImage? {
        UIGraphicsBeginImageContextWithOptions(layer.frame.size, layer.isOpaque, scale)
        defer {
            UIGraphicsEndImageContext()
        }
        guard let ctx = UIGraphicsGetCurrentContext() else { return nil }
        layer.render(in: ctx)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        return image
    }

    // MARK: 1.5墩朦、設(shè)置圖片透明度
    /// 設(shè)置圖片透明度
    /// alpha: 透明度
    /// - Returns: newImage
    func imageByApplayingAlpha(_ alpha: CGFloat) -> UIImage {
        UIGraphicsBeginImageContext(size)
        let context = UIGraphicsGetCurrentContext()
        let area = CGRect(x: 0, y: 0, width: size.width, height: size.height)
        context?.scaleBy(x: 1, y: -1)
        context?.translateBy(x: 0, y: -area.height)
        context?.setBlendMode(.multiply)
        context?.setAlpha(alpha)
        context?.draw(self.cgImage!, in: area)
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage ?? self
    }

    // MARK: 1.6、裁剪給定區(qū)域
    /// 裁剪給定區(qū)域
    /// - Parameter crop: 裁剪區(qū)域
    /// - Returns: 剪裁后的圖片
     func cropWithCropRect( _ crop: CGRect) -> UIImage? {
        let cropRect = CGRect(x: crop.origin.x * self.scale, y: crop.origin.y * self.scale, width: crop.size.width * self.scale, height: crop.size.height *  self.scale)
        if cropRect.size.width <= 0 || cropRect.size.height <= 0 {
            return nil
        }
       var image:UIImage?
        autoreleasepool{
            let imageRef: CGImage?  = self.cgImage!.cropping(to: cropRect)
            if let imageRef = imageRef {
                image = UIImage(cgImage: imageRef)
            }
        }
        return image
    }

    // MARK: 1.7翻擒、給圖片添加文字水印
    /// 給圖片添加文字水印
    /// - Parameters:
    ///   - drawTextframe: 水印的 frame
    ///   - drawText: 水印文字
    ///   - withAttributes: 水印富文本
    /// - Returns: 返回水印圖片
    func drawTextInImage(drawTextframe: CGRect, drawText: String, withAttributes: [NSAttributedString.Key : Any]? = nil) -> UIImage {
        // 開(kāi)啟圖片上下文
        UIGraphicsBeginImageContext(self.size)
        // 圖形重繪
        self.draw(in: CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height))
        // 水印文字屬性
        let attributes = withAttributes
        // 水印文字和大小
        let text = NSString(string: drawText)
        // 獲取富文本的 size
        // let size = text.size(withAttributes: attributes)
        // 繪制文字
        text.draw(in: drawTextframe, withAttributes: attributes)
        // 從當(dāng)前上下文獲取圖片
        let image = UIGraphicsGetImageFromCurrentImageContext()
        // 關(guān)閉上下文
        UIGraphicsEndImageContext()
    
        return image! 
    }
}

二氓涣、UIColor 生成的圖片 和 生成漸變色圖片

// MARK:- 二牛哺、UIColor 生成的圖片 和 生成漸變色圖片
public extension UIImage {

    // MARK: 2.1、生成指定尺寸的純色圖像
    /// 生成指定尺寸的純色圖像
    /// - Parameters:
    ///   - color: 圖片顏色
    ///   - size: 圖片尺寸
    /// - Returns: 返回對(duì)應(yīng)的圖片
    static func image(color: UIColor, size: CGSize = CGSize(width: 1.0, height: 1.0)) -> UIImage? {
        return image(color: color, size: size, corners: .allCorners, radius: 0)
    }

    // MARK: 2.2劳吠、生成指定尺寸和圓角的純色圖像
    /// 生成指定尺寸和圓角的純色圖像
    /// - Parameters:
    ///   - color: 圖片顏色
    ///   - size: 圖片尺寸
    ///   - corners: 剪切的方式
    ///   - round: 圓角大小
    /// - Returns: 返回對(duì)應(yīng)的圖片
    static func image(color: UIColor, size: CGSize, corners: UIRectCorner, radius: CGFloat) -> UIImage? {
        let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
        UIGraphicsBeginImageContextWithOptions(size, false, UIScreen.main.scale)
        let context = UIGraphicsGetCurrentContext()
        if radius > 0 {
            let path = UIBezierPath(roundedRect: rect, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
            color.setFill()
            path.fill()
        } else {
            context?.setFillColor(color.cgColor)
            context?.fill(rect)
        }
        let img = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return img
    }

    enum GradientDirection {
        case horizontal // 水平從左到右
        case vertical // 垂直從上到下
        case leftOblique // 左上到右下
        case rightOblique // 右上到左下
        case other(CGPoint, CGPoint)
    
        public func point(size: CGSize) -> (CGPoint, CGPoint) {
            switch self {
            case .horizontal:
                return (CGPoint.init(x: 0, y: 0), CGPoint.init(x: size.width, y: 0))
            case .vertical:
                return (CGPoint.init(x: 0, y: 0), CGPoint.init(x: 0, y: size.height))
            case .leftOblique:
                return (CGPoint.init(x: 0, y: 0), CGPoint.init(x: size.width, y: size.height))
            case .rightOblique:
                return (CGPoint.init(x: size.width, y: 0), CGPoint.init(x: 0, y: size.height))
            case .other(let stat, let end):
                return (stat, end)
            }
        }
    }

    // MARK: 2.3引润、生成漸變色的圖片 ["#B0E0E6", "#00CED1", "#2E8B57"]
    /// 生成漸變色的圖片 ["#B0E0E6", "#00CED1", "#2E8B57"]
    /// - Parameters:
    ///   - hexsString: 十六進(jìn)制字符數(shù)組
    ///   - size: 圖片大小
    ///   - locations: locations 數(shù)組
    ///   - direction: 漸變的方向
    /// - Returns: 漸變的圖片
    static func gradient(_ hexsString: [String], size: CGSize = CGSize(width: 1, height: 1), locations:[CGFloat]? = nil, direction: GradientDirection = .horizontal) -> UIImage? {
        return gradient(hexsString.map{ UIColor.hexStringColor(hexString: $0) }, size: size, locations: locations, direction: direction)
    }

    // MARK: 2.4、生成漸變色的圖片 [UIColor, UIColor, UIColor]
    /// 生成漸變色的圖片 [UIColor, UIColor, UIColor]
    /// - Parameters:
    ///   - colors: UIColor 數(shù)組
    ///   - size: 圖片大小
    ///   - locations: locations 數(shù)組
    ///   - direction: 漸變的方向
    /// - Returns: 漸變的圖片
    static func gradient(_ colors: [UIColor], size: CGSize = CGSize(width: 10, height: 10), locations:[CGFloat]? = nil, direction: GradientDirection = .horizontal) -> UIImage? {
        return gradient(colors, size: size, radius: 0, locations: locations, direction: direction)
    }

    // MARK: 2.5赴背、生成帶圓角漸變色的圖片 [UIColor, UIColor, UIColor]
    /// 生成帶圓角漸變色的圖片 [UIColor, UIColor, UIColor]
    /// - Parameters:
    ///   - colors: UIColor 數(shù)組
    ///   - size: 圖片大小
    ///   - radius: 圓角
    ///   - locations: locations 數(shù)組
    ///   - direction: 漸變的方向
    /// - Returns: 帶圓角的漸變的圖片
    static func gradient(_ colors: [UIColor],
                         size: CGSize = CGSize(width: 10, height: 10),
                         radius: CGFloat,
                         locations:[CGFloat]? = nil,
                         direction: GradientDirection = .horizontal) -> UIImage? {
        if colors.count == 0 { return nil }
        if colors.count == 1 {
            return UIImage.image(color: colors[0])
        }
        UIGraphicsBeginImageContext(size)
        let context = UIGraphicsGetCurrentContext()
        let path = UIBezierPath(roundedRect: CGRect(x: 0, y: 0, width: size.width, height: size.height), cornerRadius: radius)
        path.addClip()
        context?.addPath(path.cgPath)
        guard let gradient = CGGradient(colorsSpace: CGColorSpaceCreateDeviceRGB(), colors: colors.map{$0.cgColor} as CFArray, locations: locations?.map { CGFloat($0) }) else { return nil
        }
        let directionPoint = direction.point(size: size)
        context?.drawLinearGradient(gradient, start: directionPoint.0, end: directionPoint.1, options: .drawsBeforeStartLocation)
    
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }
}

三椰拒、圖片的拉伸和縮放

// MARK:- 三、圖片的拉伸和縮放
public extension UIImage {

    // MARK: 3.1凰荚、獲取固定大小的 image
    /// 獲取固定大小的image
    /// - Parameter size: 圖片尺寸
    /// - Returns: 固定大小的 image
    func solidTo(size: CGSize) -> UIImage? {
        let w = size.width
        let h = size.height
        if self.size.height <= self.size.width {
            if self.size.width >= w {
                let scaleImage = fixOrientation().scaleTo(size: CGSize(width: w, height: w * self.size.height / self.size.width))
                return scaleImage
            } else {
                return fixOrientation()
            }
        } else {
            if self.size.height >= h {
                let scaleImage = fixOrientation().scaleTo(size: CGSize(width: h * self.size.width / self.size.height, height: h))
                return scaleImage
            } else {
                return fixOrientation()
            }
        }
    }

    // MARK: 3.2燃观、按寬高比系數(shù)：等比縮放
    /// 按寬高比系數(shù)：等比縮放
    /// - Parameter scale: 要縮放的 寬高比 系數(shù)
    /// - Returns: 等比縮放 后的圖片
    func scaleTo(scale: CGFloat) -> UIImage? {
        let w = self.size.width
        let h = self.size.height
        let scaledW = w * scale
        let scaledH = h * scale
        UIGraphicsBeginImageContext(size)
        self.draw(in: CGRect(x: 0, y: 0, width: scaledW, height: scaledH))
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage;
    }

    // MARK: 3.3、按指定尺寸等比縮放
    /// 按指定尺寸等比縮放
    /// - Parameter size: 要縮放的尺寸
    /// - Returns: 縮放后的圖片
    func scaleTo(size: CGSize) -> UIImage? {
        if self.cgImage == nil { return nil }
        var w = CGFloat(self.cgImage!.width)
        var h = CGFloat(self.cgImage!.height)
        let verticalRadio = size.height / h
        let horizontalRadio = size.width / w
        var radio: CGFloat = 1
        if verticalRadio > 1 && horizontalRadio > 1 {
            radio = verticalRadio > horizontalRadio ? horizontalRadio : verticalRadio
        } else {
            radio = verticalRadio < horizontalRadio ? verticalRadio : horizontalRadio
        }
        w = w * radio;
        h = h * radio;
        let xPos = (size.width - w) / 2;
        let yPos = (size.height - h) / 2;
        UIGraphicsBeginImageContext(size);
        draw(in: CGRect(x: xPos, y: yPos, width: w, height: h))
        let scaledImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        return scaledImage;
    }

    // MARK: 3.4便瑟、圖片中間 1*1 拉伸——如氣泡一般
    /// 圖片中間1*1拉伸——如氣泡一般
    /// - Returns: 拉伸后的圖片
    func strechAsBubble() -> UIImage {
        let top = self.size.height * 0.5;
        let left = self.size.width * 0.5;
        let bottom = self.size.height * 0.5;
        let right = self.size.width * 0.5;
        let edgeInsets = UIEdgeInsets(top: top, left: left, bottom: bottom, right: right);
        // 拉伸
        return self.resizableImage(withCapInsets: edgeInsets, resizingMode: .stretch)
    }

    // MARK: 3.5缆毁、調(diào)整圖像方向 避免圖像有旋轉(zhuǎn)
    /// 調(diào)整圖像方向 避免圖像有旋轉(zhuǎn)
    /// - Returns: 返正常的圖片
    func fixOrientation() -> UIImage {
        if imageOrientation == .up {
            return self
        }
        var transform: CGAffineTransform = CGAffineTransform.identity
        switch imageOrientation {
        case .down, .downMirrored:
            transform = transform.translatedBy(x: size.width, y: size.height)
            transform = transform.rotated(by: .pi)
        case .left, .leftMirrored:
            transform = transform.translatedBy(x: size.width, y: 0)
            transform = transform.rotated(by: .pi / 2)
        case .right, .rightMirrored:
            transform = transform.translatedBy(x: 0, y: size.height)
            transform = transform.rotated(by: -.pi / 2)
        default:
            break
        }
        switch imageOrientation {
        case .upMirrored, .downMirrored:
            transform.translatedBy(x: size.width, y: 0)
            transform.scaledBy(x: -1, y: 1)
        case .leftMirrored, .rightMirrored:
            transform.translatedBy(x: size.height, y: 0)
            transform.scaledBy(x: -1, y: 1)
        default:
            break
        }
        let ctx: CGContext = CGContext(data: nil, width: Int(size.width), height: Int(size.height), bitsPerComponent: (self.cgImage?.bitsPerComponent)!, bytesPerRow: 0, space: (self.cgImage?.colorSpace)!, bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue)!
        ctx.concatenate(transform)
        switch imageOrientation {
        case .left, .leftMirrored, .right, .rightMirrored:
            ctx.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: size.height, height: size.width))
        default:
            ctx.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
        }
        let cgImage: CGImage = ctx.makeImage()!
        return UIImage(cgImage: cgImage)
    }
}

四、UIImage 壓縮相關(guān)

// MARK:- 四到涂、UIImage 壓縮相關(guān)
public extension UIImage {

    // MARK: 4.1脊框、壓縮圖片
    /// 壓縮圖片
    /// - Parameter mode: 壓縮模式
    /// - Returns: 壓縮后Data
    func compress(mode: CompressionMode = .medium) -> Data? {
        return resizeIO(resizeSize: mode.resize(size))?.compressDataSize(maxSize: mode.maxDataSize)
    }

    // MARK: 4.2、異步圖片壓縮
    /// 異步圖片壓縮
    /// - Parameters:
    ///   - mode: 壓縮模式
    ///   - queue: 壓縮隊(duì)列
    ///   - complete: 完成回調(diào)(壓縮后Data, 調(diào)整后分辨率)
    func asyncCompress(mode: CompressionMode = .medium, queue: DispatchQueue = DispatchQueue.global(), complete:@escaping (Data?, CGSize) -> Void) {
        queue.async {
            let data = self.resizeIO(resizeSize: mode.resize(self.size))?.compressDataSize(maxSize: mode.maxDataSize)
            DispatchQueue.main.async {
                complete(data, mode.resize(self.size))
            }
       }
    }

    // MARK: 4.3践啄、壓縮圖片質(zhì)量
    /// 壓縮圖片質(zhì)量
    /// - Parameter maxSize: 最大數(shù)據(jù)大小
    /// - Returns: 壓縮后數(shù)據(jù)
    func compressDataSize(maxSize: Int = 1024 * 1024 * 2) -> Data? {
        let maxSize = maxSize
        var quality: CGFloat = 0.8
        var data = self.jpegData(compressionQuality: quality)
        var dataCount = data?.count ?? 0
    
        while (data?.count ?? 0) > maxSize {
            if quality <= 0.6 {
                break
            }
            quality  = quality - 0.05
            data = self.jpegData(compressionQuality: quality)
            if (data?.count ?? 0) <= dataCount {
                break
            }
            dataCount = data?.count ?? 0
        }
        return data
    }

    // MARK: 4.4浇雹、ImageIO 方式調(diào)整圖片大小 性能很好
    /// ImageIO 方式調(diào)整圖片大小 性能很好
    /// - Parameter resizeSize: 圖片調(diào)整Size
    /// - Returns: 調(diào)整后圖片
    func resizeIO(resizeSize: CGSize) -> UIImage? {
        if size == resizeSize {
            return self
        }
        guard let imageData = pngData() else { return nil }
        guard let imageSource = CGImageSourceCreateWithData(imageData as CFData, nil) else { return nil }
    
        let maxPixelSize = max(size.width, size.height)
        let options = [kCGImageSourceCreateThumbnailWithTransform: true,
                   kCGImageSourceCreateThumbnailFromImageIfAbsent: true,
                   kCGImageSourceThumbnailMaxPixelSize: maxPixelSize]  as CFDictionary
    
        let resizedImage = CGImageSourceCreateThumbnailAtIndex(imageSource, 0, options).flatMap{
            UIImage(cgImage: $0)
        }
    
        return resizedImage
    }

    // MARK: 4.5、CoreGraphics 方式調(diào)整圖片大小 性能很好
    /// CoreGraphics 方式調(diào)整圖片大小 性能很好
    /// - Parameter resizeSize: 圖片調(diào)整Size
    /// - Returns: 調(diào)整后圖片
    func resizeCG(resizeSize: CGSize) -> UIImage? {
        if size == resizeSize {
            return self
        }
        guard  let cgImage = self.cgImage else { return nil }
        guard  let colorSpace = cgImage.colorSpace else { return nil }
        guard let context = CGContext(data: nil,
                                  width: Int(resizeSize.width),
                                  height: Int(resizeSize.height),
                                  bitsPerComponent: cgImage.bitsPerComponent,
                                  bytesPerRow: cgImage.bytesPerRow,
                                  space: colorSpace,
                                  bitmapInfo: cgImage.bitmapInfo.rawValue) else { return nil }
        context.interpolationQuality = .high
        context.draw(cgImage, in: CGRect(origin: .zero, size: resizeSize))
        let resizedImage = context.makeImage().flatMap {
            UIImage(cgImage: $0)
        }
        return resizedImage
    }
}

// MARK: 壓縮模式
public enum CompressionMode {
    /// 分辨率規(guī)則
    private static let resolutionRule: (min: CGFloat, max: CGFloat, low: CGFloat, default: CGFloat, high: CGFloat) = (10, 4096, 512, 1024, 2048)
    /// 數(shù)據(jù)大小規(guī)則
    private static let  dataSizeRule: (min: Int, max: Int, low: Int, default: Int, high: Int) = (1024 * 10, 1024 * 1024 * 20, 1024 * 512, 1024 * 1024 * 2, 1024 * 1024 * 10)
    // 低質(zhì)量
    case low
    // 中等質(zhì)量 默認(rèn)
    case medium
    // 高質(zhì)量
    case high
    // 自定義(最大分辨率, 最大輸出數(shù)據(jù)大小)
    case other(CGFloat, Int)

    fileprivate var maxDataSize: Int {
        switch self {
        case .low:
            return CompressionMode.dataSizeRule.low
        case .medium:
            return CompressionMode.dataSizeRule.default
        case .high:
            return CompressionMode.dataSizeRule.high
        case .other(_, let dataSize):
            if dataSize < CompressionMode.dataSizeRule.min {
                return CompressionMode.dataSizeRule.default
            }
            if dataSize > CompressionMode.dataSizeRule.max {
                return CompressionMode.dataSizeRule.max
            }
            return dataSize
        }
    }

    fileprivate func resize(_ size: CGSize) -> CGSize {
        if size.width < CompressionMode.resolutionRule.min || size.height < CompressionMode.resolutionRule.min {
            return size
        }
        let maxResolution = maxSize
        let aspectRatio = max(size.width, size.height) / maxResolution
        if aspectRatio <= 1.0 {
            return size
        } else {
            let resizeWidth = size.width / aspectRatio
            let resizeHeighth = size.height / aspectRatio
            if resizeHeighth < CompressionMode.resolutionRule.min || resizeWidth < CompressionMode.resolutionRule.min {
                return size
            } else {
                return CGSize.init(width: resizeWidth, height: resizeHeighth)
            }
        }
    }

    fileprivate var maxSize: CGFloat {
        switch self {
        case .low:
            return CompressionMode.resolutionRule.low
        case .medium:
            return CompressionMode.resolutionRule.default
        case .high:
            return CompressionMode.resolutionRule.high
        case .other(let size, _):
            if size < CompressionMode.resolutionRule.min {
                return CompressionMode.resolutionRule.default
            }
            if size > CompressionMode.resolutionRule.max {
                return CompressionMode.resolutionRule.max
            }
            return size
        }
    }
}

五屿讽、二維碼的處理

// MARK:- 五昭灵、二維碼的處理
public extension UIImage {

    // MARK: 5.1、生成二維碼圖片
    /// 生成二維碼圖片
    /// - Parameters:
    ///   - content: 二維碼里面的內(nèi)容
    ///   - size: 二維碼的大小
    ///   - logoSize: logo的大小
    ///   - logoImage: logo圖片
    /// - Returns: 返回生成二維碼圖片
    static func QRImage(with content: String, size: CGSize, isLogo: Bool = true, logoSize: CGSize?, logoImage: UIImage? = nil, logoRoundCorner: CGFloat? = nil) -> UIImage? {
        // 1伐谈、創(chuàng)建名為"CIQRCodeGenerator"的CIFilter
        let filter = CIFilter(name: "CIQRCodeGenerator")
        // 2烂完、將filter所有屬性設(shè)置為默認(rèn)值
        filter?.setDefaults()
        // 3、將所需盡心轉(zhuǎn)為UTF8的數(shù)據(jù)诵棵，并設(shè)置給filter
        let data = content.data(using: String.Encoding.utf8)
        filter?.setValue(data, forKey: "inputMessage")
        // 4抠蚣、設(shè)置二維碼的糾錯(cuò)水平，越高糾錯(cuò)水平越高履澳，可以污損的范圍越大
        /*
         L: 7%
         M: 15%
         Q: 25%
         H: 30%
         */
        filter?.setValue("H", forKey: "inputCorrectionLevel")
        // 5嘶窄、拿到二維碼圖片，此時(shí)的圖片不是很清晰距贷，需要二次加工
        guard let outPutImage = filter?.outputImage else { return nil }
    
        return getHDImgWithCIImage(with: outPutImage, size: size, isLogo: isLogo, logoSize: logoSize, logoImage: logoImage, logoRoundCorner: logoRoundCorner)
    }

    // MARK: 調(diào)整二維碼清晰度柄冲，添加水印圖片
    /// 調(diào)整二維碼清晰度，添加水印圖片
    /// - Parameters:
    ///   - image: 模糊的二維碼圖片
    ///   - size: 二維碼的寬高
    ///   - logoSize: logo的大小
    ///   - logoImage: logo圖片
    /// - Returns: 添加 logo 圖片后储耐，清晰的二維碼圖片
    private static func getHDImgWithCIImage(with image: CIImage, size: CGSize, isLogo: Bool = true, logoSize: CGSize?, logoImage: UIImage? = nil, logoRoundCorner: CGFloat? = nil) -> UIImage? {
        let extent = image.extent.integral
        let scale = min(size.width / extent.width, size.height / extent.height)
        //1.創(chuàng)建bitmap
        let width = extent.width * scale
        let height = extent.height * scale
    
        // 創(chuàng)建基于GPU的CIContext對(duì)象,性能和效果更好
        let context = CIContext(options: nil)
        // 創(chuàng)建CoreGraphics image
        guard let bitmapImage = context.createCGImage(image, from: extent) else { return nil }
    
        // 創(chuàng)建一個(gè)DeviceGray顏色空間
        let cs = CGColorSpaceCreateDeviceGray()
        // CGBitmapContextCreate(void * _Nullable data, size_t width, size_t height, size_t bitsPerComponent, size_t bytesPerRow, CGColorSpaceRef  _Nullable space, uint32_t bitmapInfo)
        // width：圖片寬度像素
        // height：圖片高度像素
        // bitsPerComponent：每個(gè)顏色的比特值羊初，例如在rgba-32模式下為8
        // bitmapInfo：指定的位圖應(yīng)該包含一個(gè)alpha通道
        let bitmapRef = CGContext(data: nil, width: Int(width), height: Int(height), bitsPerComponent: 8, bytesPerRow: 0, space: cs, bitmapInfo: CGImageAlphaInfo.none.rawValue) //圖形上下文滨溉，畫布
        bitmapRef?.interpolationQuality = CGInterpolationQuality.none //寫入質(zhì)量
        bitmapRef?.scaleBy(x: scale, y: scale) //調(diào)整“畫布”的縮放
        bitmapRef?.draw(bitmapImage, in: extent) //繪制圖片
    
        //2.保存bitmap到圖片
        guard let scaledImage = bitmapRef?.makeImage() else { return nil }
    
        // 清晰的二維碼圖片
        let outputImage = UIImage(cgImage: scaledImage)
    
        guard isLogo == true, let logoSize = logoSize, let logoImage = logoImage else {
            return outputImage
        }
    
        var newLogo: UIImage = logoImage
        if let newLogoRoundCorner = logoRoundCorner, let roundCornerLogo = logoImage.isRoundCorner(radius: newLogoRoundCorner, byRoundingCorners: .allCorners, imageSize: logoSize) {
            newLogo = roundCornerLogo
        }
    
        // 給二維碼加 logo 圖
        UIGraphicsBeginImageContextWithOptions(outputImage.size, false, UIScreen.main.scale)
        outputImage.draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
        // 把水印圖片畫到生成的二維碼圖片上什湘，注意尺寸不要太大（根據(jù)上面生成二維碼設(shè)置的糾錯(cuò)程度設(shè)置）长赞，否則有可能造成掃不出來(lái)
        let waterImgW = logoSize.width
        let waterImgH = logoSize.height
        let waterImgX = (size.width - waterImgW) * 0.5
        let waterImgY = (size.height - waterImgH) * 0.5
        newLogo.draw(in: CGRect(x: waterImgX, y: waterImgY, width: waterImgW, height: waterImgH))
        let newPicture = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
    
        return newPicture
    }
}

六、gif 加載

// MARK:- 六闽撤、pdf 加載
public enum DataType: String {
    case gif    = "gif"
    case png    = "png"
    case jpeg   = "jpeg"
    case tiff   = "tiff"
    case defaultType
}
public extension UIImage {

    // MARK: 6.1得哆、驗(yàn)證資源的格式，返回資源格式（png/gif/jpeg...）
    /// 驗(yàn)證資源的格式哟旗，返回資源格式（png/gif/jpeg...）
    /// - Parameter data: 資源
    /// - Returns: 返回資源格式（png/gif/jpeg...）
    static func checkImageDataType(data: Data?) -> DataType {
        guard data != nil else {
            return .defaultType
        }
        let c = data![0]
        switch (c) {
        case 0xFF:
            return .jpeg
        case 0x89:
            return .png
        case 0x47:
            return .gif
        case 0x49, 0x4D:
            return .tiff
        default:
            return .defaultType
        }
    }

    // MARK: 6.2贩据、加載 data 數(shù)據(jù)的 gif 圖片
    /// 加載 data 數(shù)據(jù)的 gif 圖片
    /// - Parameter data: data 數(shù)據(jù)
    static func gif(data: Data) -> UIImage? {
        // Create source from data
        guard let source = CGImageSourceCreateWithData(data as CFData, nil) else {
            print("SwiftGif: Source for the image does not exist")
            return nil
        }
        return UIImage.animatedImageWithSource(source)
    }

    // MARK: 6.3、加載網(wǎng)絡(luò) url 的 gif 圖片
    /// 加載網(wǎng)絡(luò) url 的 gif 圖片
    /// - Parameter url: gif圖片的網(wǎng)絡(luò)地址
    static func gif(url: String) -> UIImage? {
        // Validate URL
        guard let bundleURL = URL(string: url) else {
            print("SwiftGif: This image named \"\(url)\" does not exist")
            return nil
        }
        // Validate data
        guard let imageData = try? Data(contentsOf: bundleURL) else {
            print("SwiftGif: Cannot turn image named \"\(url)\" into NSData")
            return nil
        }
    
        return gif(data: imageData)
    }

    // MARK: 6.4闸餐、加載本地的gif圖片
    /// 加載本地的gif圖片
    /// - Parameter name:圖片的名字
    static func gif(name: String) -> UIImage? {
        // Check for existance of gif
        guard let bundleURL = Bundle.main
            .url(forResource: name, withExtension: "gif") else {
            print("SwiftGif: This image named \"\(name)\" does not exist")
            return nil
        }
        // Validate data
        guard let imageData = try? Data(contentsOf: bundleURL) else {
            print("SwiftGif: Cannot turn image named \"\(name)\" into NSData")
            return nil
        }
        
        return gif(data: imageData)
    }

    // MARK: 6.5饱亮、加載 asset 里面的圖片
    /// 加載 asset 里面的圖片
    /// - Parameter asset: asset 里面的圖片名字
    @available(iOS 9.0, *)
    static func gif(asset: String) -> UIImage? {
        // Create source from assets catalog
        guard let dataAsset = NSDataAsset(name: asset) else {
            print("SwiftGif: Cannot turn image named \"\(asset)\" into NSDataAsset")
            return nil
        }
        return gif(data: dataAsset.data)
    }

    private class func delayForImageAtIndex(_ index: Int, source: CGImageSource!) -> Double {
        var delay = 0.1
        // Get dictionaries
        let cfProperties = CGImageSourceCopyPropertiesAtIndex(source, index, nil)
        let gifPropertiesPointer = UnsafeMutablePointer<UnsafeRawPointer?>.allocate(capacity: 0)
        defer {
            gifPropertiesPointer.deallocate()
        }
        let unsafePointer = Unmanaged.passUnretained(kCGImagePropertyGIFDictionary).toOpaque()
        if CFDictionaryGetValueIfPresent(cfProperties, unsafePointer, gifPropertiesPointer) == false {
            return delay
        }
        let gifProperties: CFDictionary = unsafeBitCast(gifPropertiesPointer.pointee, to: CFDictionary.self)
        // Get delay time
        var delayObject: AnyObject = unsafeBitCast(
            CFDictionaryGetValue(gifProperties,
                             Unmanaged.passUnretained(kCGImagePropertyGIFUnclampedDelayTime).toOpaque()),
            to: AnyObject.self)
        if delayObject.doubleValue == 0 {
            delayObject = unsafeBitCast(CFDictionaryGetValue(gifProperties,
                                                         Unmanaged.passUnretained(kCGImagePropertyGIFDelayTime).toOpaque()), to: AnyObject.self)
        }
        if let delayObject = delayObject as? Double, delayObject > 0 {
            delay = delayObject
        } else {
            // Make sure they're not too fast
                delay = 0.1
    }
        return delay
    }

    private static func gcdForPair(_ lhs: Int?, _ rhs: Int?) -> Int {
        var lhs = lhs
        var rhs = rhs
        // Check if one of them is nil
        if rhs == nil || lhs == nil {
            if rhs != nil {
                return rhs!
            } else if lhs != nil {
                return lhs!
            } else {
                return 0
            }
        }
        // Swap for modulo
        if lhs! < rhs! {
            let ctp = lhs
            lhs = rhs
            rhs = ctp
        }
        // Get greatest common divisor
        var rest: Int
        while true {
            rest = lhs! % rhs!
        
            if rest == 0 {
                return rhs!
            } else {
                lhs = rhs
                rhs = rest
            }
        }
    }

    private static func gcdForArray(_ array: [Int]) -> Int {
        if array.isEmpty {
            return 1
        }
    
        var gcd = array[0]
    
        for val in array {
            gcd = UIImage.gcdForPair(val, gcd)
        }
    
        return gcd
    }

    private static func animatedImageWithSource(_ source: CGImageSource) -> UIImage? {
        let count = CGImageSourceGetCount(source)
        var images = [CGImage]()
        var delays = [Int]()
        // Fill arrays
        for index in 0..<count {
            // Add image
            if let image = CGImageSourceCreateImageAtIndex(source, index, nil) {
                images.append(image)
            }
            // At it's delay in cs
            let delaySeconds = UIImage.delayForImageAtIndex(Int(index),
                                                        source: source)
            delays.append(Int(delaySeconds * 1000.0)) // Seconds to ms
        }
    
        // Calculate full duration
        let duration: Int = {
            var sum = 0
            for val: Int in delays {
                sum += val
            }
            return sum
        }()
        // Get frames
        let gcd = gcdForArray(delays)
        var frames = [UIImage]()
        var frame: UIImage
        var frameCount: Int
        for index in 0..<count {
            frame = UIImage(cgImage: images[Int(index)])
            frameCount = Int(delays[Int(index)] / gcd)
        
            for _ in 0..<frameCount {
                frames.append(frame)
            }
        }
        // Heyhey
        let animation = UIImage.animatedImage(with: frames,
                                          duration: Double(duration) / 1000.0)
        return animation
    }
}