iOS7 ALAsset缩略图方向错误

Question

I'm trying to load images (taken earlier from the UIImagePickerController and saved in the Assets Library) from the ALAssetsLibrary in iOS7 in Swift using the code below:

assetsLibrary.assetForURL(NSURL(string: image.diskPath), resultBlock: {
            asset in
            if let validAsset = asset {
                let rep = validAsset.defaultRepresentation()
                let imageData = rep.fullResolutionImage()
                //let imageData = validAsset.thumbnail()
                var imageOrientation: UIImageOrientation = .Down
                let orientValueFromImage = validAsset.valueForProperty("ALAssetPropertyOrientation") as NSNumber
                imageOrientation = UIImageOrientation.fromRaw(orientValueFromImage.integerValue)!

                let imageToAdd = UIImage(CGImage: imageData.takeUnretainedValue(), scale: 1, orientation: imageOrientation)
                self.imagesForCollectionView.append(imageToAdd)
                fetchedImageCount++
                if fetchedImageCount == fetchedImages.count{
                    self.collectionView.reloadData()
                }
            }
            }, failureBlock: {error in
                NSLog("error %@", error.debugDescription)
            })

When I use let imageData = rep.fullResolutionImage(), I get the correct UIImageOrientation for the image, but when I replace that line with let imageData = validAsset.thumbnail(), I always get a .Right Orientation. This happens only with images taken through the UIImagePickerController. Any Ideas on why this is happening and how to fix it? Loading a full resolution image for a UICollectionView is a bummer and takes a lot of time and memory.

How can I get the correct orientation of the thumbnail? Thanks.

Answer 1

Have you tried something like :

UIImage(CGImage:asset?.aspectRatioThumbnail().takeUnretainedValue())

aspectRatioThumbnail() gives you a thumbnail that have the same ratio and orientation as the full resolution image.

Like you I used scale and orientation parameters for UIImage init and got wrong orientation, I then tried without and the orientation is always correct.