How to copy an UIImage?

Question

I have an UIImageView with an UIImage. I want to assign a copy of these picture to two variables. Based on what the user is doing the image should be manipulated. The problem is, the image is the same in each variables. I guess, because they are passed by reference.

let image1 = imageView.image!
let image2 = imageView.image!

How do I get two separate copies of this image?

What I want to achieve: Just crop the one image, keep the other like the original.

let imageLeft = googleImageView.image!
let imageRef = CGImageCreateCopy(googleImageView.image!.CGImage)
let imageRight = UIImage(CGImage: imageRef!, scale: googleImageView.image!.scale, orientation: googleImageView.image!.imageOrientation)

if translation.x < 0 {
    let scale = imageLeft.scale
    let newRect = CGRectMake(0, 0, (imageLeft.size.width + translation.x) * scale, imageLeft.size.height * scale)
    let imageRef = CGImageCreateWithImageInRect(imageLeft.CGImage, newRect)
    
    if let croppedImage = imageRef {
        googleImageView.image = UIImage(CGImage: croppedImage, scale: scale, orientation: imageLeft.imageOrientation)
    }
} 
print("left image: \(imageLeft) right image \(imageRight)")

The code above prints to the console:

left image: <UIImage: 0x7fd020dca070>, {111, 167} 
right image <UIImage: 0x7fd020dda430>, {111, 167}
left image: <UIImage: 0x7fd020df9ba0>, {110, 167} 
right image <UIImage: 0x7fd020d45670>, {110, 167}

... and so on. So, BOTH images gets a new size. Only the left Image should get cropped.

http://stackoverflow.com/a/6770387/3324388 – Aggressor Jun 30 '15 at 06:00 — Aggressor, Jun 30 '15 at 06:00

score 15 · Accepted Answer · answered Jun 30 '15 at 06:06

15

As @Aggressor suggested you can copy your image from imageView this way:

let newCgIm = CGImageCreateCopy(imageView.image?.CGImage)
let newImage = UIImage(CGImage: newCgIm, scale: imageView.image!.scale, orientation: imageView.image!.imageOrientation)

answered Jun 30 '15 at 06:06

Dharmesh Kheni

71,228
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Follow-up question: The image gets copied, BUT it is still manipulated like the first one. Any idea why this is the case? – heikomania Jun 30 '15 at 07:13
This code will take Image from `imageView ` and save it to another `newImage ` and I don't know exactly what action are you performing. – Dharmesh Kheni Jun 30 '15 at 07:15
I want to do the following: Crop image1 but keep the original as image2. When I crop image1, image2 gets cropped two. I will edit my question to clarify. – heikomania Jun 30 '15 at 07:17
ok then first copy the image into another variable then perform your crop operation. – Dharmesh Kheni Jun 30 '15 at 07:19
Tried that, as you can see in my edit above. Every copy of the image gets cropped too. – heikomania Jun 30 '15 at 07:25
1

Happy to help you..:) – Dharmesh Kheni Jun 30 '15 at 07:45

abdullahselek · Answer 2 · 2017-09-20T13:49:06.887

7

There is a new copy function of cgImage comes with Swift 3 and also compatible with Swift 4. So you can use in this way

guard let cgImage = imageView.image?.cgImage?.copy() else {
        return
    }
let newImage = UIImage(cgImage: cgImage,
                       scale: imageView.image!.scale,
                       orientation: imageView.image!.imageOrientation)

edited Sep 20 '17 at 13:49

answered Apr 04 '17 at 11:49

abdullahselek

7,893
3
50
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Jochen Holzer · Answer 3 · 2021-09-25T11:47:40.103

Solution for Swift 5 or better:

Add this extension to your code

extension UIImage {
    func clone() -> UIImage? {
        guard let originalCgImage = self.cgImage, let newCgImage = originalCgImage.copy() else {
            return nil
        }

        return UIImage(cgImage: newCgImage, scale: self.scale, orientation: self.imageOrientation)
    }
}

then clone the image to get a new image object and not a reference:

let image1 = imageView.image!
let image2 = image1().clone()

! Note that cloning the image increases the memory consumption.

How to copy an UIImage?

3 Answers3

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