一些UIImage扩展

压缩图片

/// compress 这个方法显然还不是最优解（耗时较长，有一瞬间的内存暴涨，存在闪退隐患），还需要优化
class func compress(_ data: Data, maxSize: CGSize? = CGSize(width: 600, height: 600), maxKB: CGFloat? = 100) -> UIImage? {
    if let image = UIImage(data: data) {
        return compress(image, maxSize: maxSize, maxKB: maxKB)
    }

    return nil
}

class func compress(_ image: UIImage, maxSize: CGSize? = CGSize(width: 600, height: 600), maxKB: CGFloat? = 100) -> UIImage? {
    if let data = image.resizeImage(maxSize: maxSize)?.resizeImageData(maxKB: maxKB) {
        return UIImage(data: data)
    }
    return image
}

class func compress(_ image: UIImage, maxSize: CGSize? = CGSize(width: 600, height: 600), maxKB: CGFloat? = 100) -> Data? {
    if let data = image.jpegData(compressionQuality: 1.0) {
        if let img = UIImage(data: data, scale: 1.0) {
            return img.resizeImage(maxSize: maxSize)?.resizeImageData(maxKB: maxKB)
        }
    }
    
    return nil
}

class func compress(onlySize data: Data, maxSize: CGSize? = CGSize(width: 600, height: 600)) -> UIImage? {
    if let image = UIImage(data: data) {
        return image.resizeImage(maxSize: maxSize)
    }
    
    return nil
}

class func compress(onlyDataSize data: Data, maxKB: CGFloat? = 100) -> UIImage? {
    if let image = UIImage(data: data) {
        if let d = image.resizeImageData(maxKB: maxKB) {
            return UIImage(data: d)
        }else {
            return image
        }
    }
    
    return nil
}

func resizeImage(maxSize: CGSize? = CGSize(width: 600, height: 600)) -> UIImage? {
    return autoreleasepool { () -> UIImage? in
        var re_size = self.size
        
        let width_scale: CGFloat = re_size.width / maxSize!.width
        let height_scale: CGFloat = re_size.height / maxSize!.height
        
        if width_scale > 1.0 && width_scale > height_scale {
            re_size = CGSize(width: self.size.width / width_scale, height: self.size.height / width_scale)
        }else if height_scale > 1.0 && height_scale > width_scale {
            re_size = CGSize(width: self.size.width / height_scale, height: self.size.height / height_scale)
        }
        
        UIGraphicsBeginImageContextWithOptions(re_size, false, UIScreen.main.scale)
        self.draw(in: CGRect(origin: .zero, size: re_size))
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        return newImage
    }
}

func resizeImageData(maxKB: CGFloat? = 100) -> Data? {
    return autoreleasepool { () -> Data? in
        if let data = self.jpegData(compressionQuality: 1.0) {
            let size = CGFloat(data.count) / 1024.0 / maxKB!
            let rate: CGFloat = (size > 1) ? (1 / (size + 1.0)) : 1.0
            let imageData = self.jpegData(compressionQuality: rate)
            
            print("- resizeImage - jpeg", data, "->", imageData ?? "0", "is main thread:", Thread.current.isMainThread)
            
            return imageData
        }else {
            //print("- resizeImage - can not to jpeg", newImage ?? "no image")
        }
        
        return nil
    }
}

/// io_compress 这个方法 速度快，内存消耗小，压缩狠(清晰度不够)，压缩的方向会有问题，需要调整图片方向
class func io_compress(_ data: Data, _ orientation: UIImage.Orientation, maxImageSize: CGSize? = nil) -> UIImage? {
    return autoreleasepool { () -> UIImage? in
        if let source = CGImageSourceCreateWithData(data as CFData, nil) {
            let maxSize: CGSize = maxImageSize ?? UIScreen.main.bounds.size
            
            let options: [CFString : Any] = [
                kCGImageSourceCreateThumbnailFromImageIfAbsent: true,
                kCGImageSourceThumbnailMaxPixelSize: max(maxSize.width, maxSize.height)
            ]
            
            if let cgImage = CGImageSourceCreateThumbnailAtIndex(source, 0, options as CFDictionary) {
                let newImage = UIImage(cgImage: cgImage, scale: 1.0, orientation: orientation)
                return newImage.fixImageOrientation()
            }
        }
        
        return nil
    }
}
///  图片方向矫正
func fixImageOrientation() -> UIImage {
    if self.imageOrientation == .up {
        return self
    }
    
    let size = self.size
    var transform: CGAffineTransform = CGAffineTransform.identity
    
    switch self.imageOrientation {
    case .left, .leftMirrored:
        transform = transform.translatedBy(x: size.width, y: 0)
        transform = transform.rotated(by: CGFloat.pi / 2)
    case .down, .downMirrored:
        transform = transform.translatedBy(x: size.width, y: size.height)
        transform = transform.rotated(by: CGFloat.pi)
    case .right, .rightMirrored:
        transform = transform.translatedBy(x: 0, y: size.height)
        transform = transform.rotated(by: -CGFloat.pi / 2)
    default:break
    }
    
    switch self.imageOrientation {
    case .upMirrored, .downMirrored:
        transform = transform.translatedBy(x: size.width, y: 0)
        transform = transform.scaledBy(x: -1, y: 1)
    case .leftMirrored, .rightMirrored:
        transform = transform.translatedBy(x: size.height, y: 0)
        transform = transform.scaledBy(x: -1, y: 1)
    default:break
    }
    
    guard let cg_image = self.cgImage else {return self}
    guard let cg_colorSpace = cg_image.colorSpace else {return self}
    
    guard let context = CGContext(data: nil,
                                  width: Int(size.width),
                                  height: Int(size.height),
                                  bitsPerComponent: cg_image.bitsPerComponent,
                                  bytesPerRow: 0,
                                  space: cg_colorSpace,
                                  bitmapInfo: cg_image.bitmapInfo.rawValue) else {return self}
    
    context.concatenate(transform)
    
    switch self.imageOrientation {
    case .left, .leftMirrored, .right, .rightMirrored:
        context.draw(cg_image, in: CGRect(x: 0, y: 0, width: size.height, height: size.width))
    default:
        context.draw(cg_image, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
    }
    
    guard let cgImg = context.makeImage() else {return self}
    
    return UIImage(cgImage: cgImg)
}

重设图片大小

func reSizeImage(_ reSize: CGSize) -> UIImage? {
    //UIGraphicsBeginImageContext(reSize);
    UIGraphicsBeginImageContextWithOptions(reSize,false,UIScreen.main.scale)
    self.draw(in: CGRect(x: 0, y: 0, width: reSize.width, height: reSize.height))
    guard let reSizeImage: UIImage = UIGraphicsGetImageFromCurrentImageContext() else {return nil}
    UIGraphicsEndImageContext()
    return reSizeImage
}

等比率缩放（依赖于重设图片大小方法）

func scaleImage(_ scale: CGFloat) -> UIImage? {
    let reSize = CGSize(width: self.size.width * scale, height: self.size.height * scale)
    return reSizeImage(reSize)
}

裁剪

func cutImage(_ rect: CGRect) -> UIImage? {
    guard let cgImage = self.cgImage?.cropping(to: rect) else {return nil}
    
    return UIImage(cgImage: cgImage)
}

func cutImageWidth(_ widthScale: CGFloat) -> UIImage? {
    guard let cgImage = self.cgImage?.cropping(to: CGRect(x: 0, y: 0, width: self.size.width * widthScale, height: self.size.height)) else {return nil}
    
    return UIImage(cgImage: cgImage)
}

合成

func composeImageWith(_ image: UIImage) -> UIImage? {
    UIGraphicsBeginImageContextWithOptions(self.size,false,UIScreen.main.scale)
    self.draw(in: CGRect(origin: CGPoint.zero, size: self.size))
    image.draw(in: CGRect(origin: CGPoint.zero, size: image.size))
    guard let reSizeImage: UIImage = UIGraphicsGetImageFromCurrentImageContext() else {return nil}
    UIGraphicsEndImageContext()
    
    return reSizeImage
}

简单渲染

func apply(_ color: UIColor, _ imageView: UIImageView) -> UIImage? {
    imageView.tintColor = color
    return self.withRenderingMode(.alwaysTemplate)
}

GIF

//通过data获取gif source//
class func getGifSource(_ data: Data) -> UIImageView.GIFSource? {
    if let source = CGImageSourceCreateWithData(data as CFData, nil) {
        var images = [UIImage]()
        var duration: TimeInterval = 0
        for i in 0..<CGImageSourceGetCount(source) {
            if let image = CGImageSourceCreateImageAtIndex(source, i, nil) {
                images.append(UIImage(cgImage: image))
            }
            if let properties = CGImageSourceCopyPropertiesAtIndex(source, i, nil) as? [CFString: Any], let dic = properties[kCGImagePropertyGIFDictionary] as? [CFString: Any], let time = dic[kCGImagePropertyGIFDelayTime] as? NSNumber {
                duration += time.doubleValue
            }
        }
        
        return (images, duration)
    }
    
    return nil
}

//通过图片路径读取gif source（相册获取的imagepath没有权限读取）//
class func getGifImageSource(_ imagePath: String) -> UIImageView.GIFSource? {
    if let url = URL(string: imagePath) {
        do {
            let data = try Data(contentsOf: url)
            
            return UIImage.getGifSource(data)
        }catch {
            print(error)
        }
    }
    
    return nil
}

//以下是UIImageView的扩展（用于展示GIF图片）  
typealias GIFSource = ([UIImage], TimeInterval)

func showGif(_ gifSource: GIFSource?) {
    guard let source = gifSource else {return}
    self.animationImages = source.0
    self.animationDuration = source.1
    self.animationRepeatCount = 0
    
    self.startAnimating()
}

添加水印

 func waterMark(_ text: String) -> UIImage? {
    let text_width: CGFloat = self.size.width / 3
    var font_size: Int = 10
    var merge: CGFloat = 20
    var standard_w: CGFloat = 0
    
    for i in font_size..<100 {
        let dic = [NSAttributedString.Key.font: UIFont.systemFont(ofSize: CGFloat(i))]
        let size = text.size(withAttributes: dic)
        
        if i == font_size {
            standard_w = size.width
        }
        
        if size.width >= text_width {
            font_size = i
            merge = merge * (size.width / standard_w)
            break
        }
    }
    
    UIGraphicsBeginImageContext(self.size)
    self.draw(in: CGRect(origin: .zero, size: self.size))
    
    let style = NSMutableParagraphStyle()
    style.lineBreakMode = .byWordWrapping
    style.alignment = .center
    
    let attrDic = [
        NSAttributedString.Key.font: UIFont.systemFont(ofSize: CGFloat(font_size)),
        NSAttributedString.Key.foregroundColor: UIColor.darkText,
        NSAttributedString.Key.paragraphStyle: style,
        NSAttributedString.Key.backgroundColor: UIColor(white: 1, alpha: 0.3)
    ]
    
    let text_size = text.size(withAttributes: attrDic)
    let rect = CGRect(x: merge, y: self.size.height - merge - text_size.height, width: text_size.width, height: text_size.height) // 左下角
    
    text.draw(in: rect, withAttributes: attrDic)
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    
    return image
}