According to the documentation, the return value of CGImageSourceCreateWithData(::) is
An image source. You are responsible for releasing this object using CFRelease.
That is to say I need to invoke CFRelease in my codes.
func downsampling(imageName: String, to pointSize: CGSize, scale: CGFloat = UIScreen.main.scale) -> UIImage? {
let imageData = NSDataAsset(name: imageName)?.data
let imageSourceOptions = [kCGImageSourceShouldCache: false]
guard let imageSource = CGImageSourceCreateWithData(imageData! as CFData, imageSourceOptions as CFDictionary) else {
return nil
}
let maxDimensionInPixels = min(pointSize.width, pointSize.height/4) * scale
let downsamplingOptions = [
kCGImageSourceCreateThumbnailFromImageAlways: true,
kCGImageSourceShouldCacheImmediately: true,
kCGImageSourceCreateThumbnailWithTransform: true,
kCGImageSourceThumbnailMaxPixelSize: maxDimensionInPixels
] as CFDictionary
guard let downsampledImage = CGImageSourceCreateImageAtIndex(imageSource, 0, downsamplingOptions) else {
return nil
}
**CFRelease(imageSource)**
return UIImage(cgImage: downsampledImage)
}
However, the compiler gives back an error
'CFRelease' is unavailable: Core Foundation objects are automatically memory managed"
Is CFRelease only suitable for oc? Is it a clerical error in the doc for swift?
