///图片压缩方法

   class func resetImgSize(sourceImage : UIImage,maxImageLenght : CGFloat,maxSizeKB : CGFloat) -> Data {

    var maxSize = maxSizeKB

    var maxImageSize = maxImageLenght

    if (maxSize <= 0.0) {

        maxSize = 1024.0;

    }

    if (maxImageSize <= 0.0)  {

        maxImageSize = 1024.0;

    }

    //先调整分辨率

    var newSize = CGSize.init(width: sourceImage.size.width, height: sourceImage.size.height)

    let tempHeight = newSize.height / maxImageSize;

    let tempWidth = newSize.width / maxImageSize;

    if (tempWidth > 1.0 && tempWidth > tempHeight) {

        newSize = CGSize.init(width: sourceImage.size.width / tempWidth, height: sourceImage.size.height / tempWidth)

    }

    else if (tempHeight > 1.0 && tempWidth < tempHeight){

        newSize = CGSize.init(width: sourceImage.size.width / tempHeight, height: sourceImage.size.height / tempHeight)

    }

    UIGraphicsBeginImageContext(newSize)

    sourceImage.draw(in: CGRect.init(x: 0, y: 0, width: newSize.width, height: newSize.height))

    let newImage = UIGraphicsGetImageFromCurrentImageContext()

    UIGraphicsEndImageContext()

    var imageData = UIImageJPEGRepresentation(newImage!, 1.0)

    var sizeOriginKB : CGFloat = CGFloat((imageData?.count)!) / 1024.0;

    //调整大小

    var resizeRate = 0.9;

    while (sizeOriginKB > maxSize && resizeRate > 0.1) {

        imageData = UIImageJPEGRepresentation(newImage!,CGFloat(resizeRate));

        sizeOriginKB = CGFloat((imageData?.count)!) / 1024.0;

        resizeRate -= 0.1;

    }

    return imageData!

   }