How to get dpi/ppi of UIImage?

Question

How to get dpi/ppi of image in iOS? Maybe raw image file contains this information, so I can get ppi/dpi from NSData? Thank you.

Answer 1

Swift 5 solution: You can get the DPI information from the image metadata. imageData is of NSData type.

  guard let imageSource = CGImageSourceCreateWithData(imageData, nil),
            let metaData = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, nil) as? [String: Any],
            let dpi = metaData["DPIWidth"] as? Int else {
                return
        }

 print(dpi)