How to get image DPI when selected from photo library in ios

Asked Jan 29 '16 at 09:44

Active Jan 29 '16 at 10:17

Viewed 76 times

I am trying to find out the DPI of the selected image from photo library but getting (null).

Using below code.

 - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

UIImage *chosenImage = info[UIImagePickerControllerOriginalImage];
NSData * imgData = UIImageJPEGRepresentation(chosenImage, 0.0);
CGImageSourceRef src = CGImageSourceCreateWithData((CFDataRef) imgData, NULL);
CFDictionaryRef imageDict = CGImageSourceCopyPropertiesAtIndex(src, 0, NULL);

// Print image dictionary
NSString *dpiHeight = CFDictionaryGetValue(imageDict, @"DPIHeight");
NSString *dpiWidth = CFDictionaryGetValue(imageDict, @"DPIWidth");   
NSLog(@"DPIHeight:%@ DPIWidth: %@",dpiHeight, dpiWidth);

}

is it correct ? can i get DPI from image data ? is there any other possibilities ?

Can any one help me will highly appreciated.

Thank you.

edited Jan 29 '16 at 10:17

asked Jan 29 '16 at 09:44

Chandan Reddy

check this link http://stackoverflow.com/a/23943401/5362916 – Uma Madhavi Jan 29 '16 at 09:46
Have you debugged that method to see if anything is `nil`? Also it looks to me like you have a memory leak after using `CGImageSourceCreateWithData()` and `CGImageSourceCopyPropertiesAtIndex()` and not releasing the returned objects? – trojanfoe Jan 29 '16 at 09:49
@trojanfoe ya you are correct how can solve this ? – Chandan Reddy Jan 29 '16 at 09:56
Nope. Have you done what I suggested? – trojanfoe Jan 29 '16 at 09:56
Ya debugged it and getting nil at dpiHeight ,dpiWidth only – Chandan Reddy Jan 29 '16 at 10:08
@ChandanReddy OK that just sounds like the DPI information is not contained in the image. See the answer I linked as duplicate. – trojanfoe Jan 29 '16 at 10:19
@trojanfoe can you check this [link](http://iosdevelopertips.com/data-file-management/get-image-data-including-depth-color-model-dpi-and-more.html) you can get DPI of image which one is not getting by using above method. – Chandan Reddy Jan 29 '16 at 10:38
The image doesn't always contain that information. You cannot obtain something which is not there. – trojanfoe Jan 29 '16 at 10:42
Finally got it check this [Github link](https://github.com/foundry/UIImageMetadata) – Chandan Reddy Feb 01 '16 at 06:29

How to get image DPI when selected from photo library in ios

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