UIImage, check if contain image

Question

If I instantiate a UIImage like this :

UIImage *image = [[UIImage alloc] init];

The object is created but it doesn't contain any image.

How I can check if my object contains an image or not?

score 69 · Accepted Answer · edited Jan 03 '20 at 20:26

69

You can check if it has any image data.

UIImage* image = [[UIImage alloc] init];

CGImageRef cgref = [image CGImage];
CIImage *cim = [image CIImage];

if (cim == nil && cgref == NULL)
{
    NSLog(@"no underlying data");
}
[image release];

Swift Version

let image = UIImage()

let cgref = image.cgImage
let cim = image.ciImage

if cim == nil && cgref == nil {
    print("no underlying data")
}

edited Jan 03 '20 at 20:26

Jalil

1,167
11
34

answered Nov 18 '11 at 12:13

Kreiri

7,840
5
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36

But [image CIImage]; availables only in iOS 5. What about 4.3 ? – Rubycon Sep 25 '12 at 15:34

onmyway133 · Answer 2 · 2017-03-23T12:14:29.350

16

Check for cgImage or ciImage, in Swift 3

public extension UIImage {

  public var hasContent: Bool {
    return cgImage != nil || ciImage != nil
  }
}

CGImage: If the UIImage object was initialized using a CIImage object, the value of the property is NULL.

CIImage: If the UIImage object was initialized using a CGImageRef, the value of the property is nil.

edited Mar 23 '17 at 12:14

answered Apr 28 '16 at 08:31

onmyway133

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31
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Crashes if there is no image... Unexpectedly found nil while unwrapping an Optional – dub Aug 20 '20 at 22:04

score 0 · Answer 3 · answered Dec 26 '13 at 10:34

0

Check with CGImageRef with itself wheather it contains null value means UIImage object not contains image.......

answered Dec 26 '13 at 10:34

Mahesh Aswathanarayana

161
10

score 0 · Answer 4 · answered May 23 '17 at 14:25

This is updated version of @Kreiri, I put in a method and fixed logic error:

- (BOOL)containsImage:(UIImage*)image {
    BOOL result = NO;

    CGImageRef cgref = [image CGImage];
    CIImage *cim = [image CIImage];

    if (cim != nil || cgref != NULL) { // contains image
        result = YES;
    }

    return result;
}

An UIImage could only based on CGImageRef or CIImage. If both is nil means there is no image. Example use of giving method:

if (![self containsImage:imageview.image]) {
    [self setImageWithYourMethod];
}

hope it will help someone.

UIImage, check if contain image

4 Answers4

Swift Version

Linked