CODEWITHSUNDEEP
iosswift
Nasir Javed
Nasir Javed

Reputation: 375

How to use compression algorithm for image compression i.e LZ4 , LZMA , ZLIB swift

I want to compress image using above lossless algorithms, but these algorithm works on data but not on image data. is there anyway to compress image using these algorithms here is a code

    var org = UIImage(named: "Dragon.jpg")
    var res: Data = UIImagePNGRepresentation(org!)!

    print("Image before Compressing")
    print(res.count)
    print(res)
    orignal.image =  UIImage(data: res)


    res = res.compress(withAlgorithm: .LZFSE)!

    print("Image After Compressing")
    print(res.count)
    print(res)


    res = res.decompress(withAlgorithm: .LZFSE)!

    print("Image After Decompressing")
    print(res)
    print(res.count)


    compress.image =
        UIImage(data: res)

OutPut Image before Compressing

1915549

1915549 bytes

Image After Compressing

1935259

1935259 bytes

Image After Decompressing

1915549

1915549 bytes

Upvotes: 3

Views: 1022

Answers (1)

Amey
Amey

Reputation: 815

Compress that data using this algorithm and from that data make image .

let image : UIImage = UIImage(data: imageData)

So U will get that image . Use This If You Want To Compress Image :- (Resolution changing)

 func compressImage(image:UIImage) -> Data? {
  

    var actualHeight : CGFloat = image.size.height
    var actualWidth : CGFloat = image.size.width
    let maxHeight : CGFloat = 2732 .0
    let maxWidth : CGFloat = 2048.0
    var imgRatio : CGFloat = actualWidth/actualHeight
    let maxRatio : CGFloat = maxWidth/maxHeight
    var compressionQuality : CGFloat = 0.5

    if (actualHeight > maxHeight || actualWidth > maxWidth){
        if(imgRatio < maxRatio){
            //adjust width according to maxHeight
            imgRatio = maxHeight / actualHeight
            actualWidth = imgRatio * actualWidth
            actualHeight = maxHeight
        }
        else if(imgRatio > maxRatio){
            //adjust height according to maxWidth
            imgRatio = maxWidth / actualWidth
            actualHeight = imgRatio * actualHeight
            actualWidth = maxWidth
        }
        else{
            actualHeight = maxHeight
            actualWidth = maxWidth
            compressionQuality = 1
        }
    }

    let rect = CGRect(x: 0.0, y: 0.0, width: actualWidth, height: actualHeight)
    UIGraphicsBeginImageContext(rect.size)
    image.draw(in: rect)
    guard let img = UIGraphicsGetImageFromCurrentImageContext() else {
        return nil
    }
    UIGraphicsEndImageContext()
    guard let imageData = UIImageJPEGRepresentation(img, compressionQuality)else{
        return nil
    }
    return imageData
}

Upvotes: 1

Related Questions