I am using ALAsset to retrieve images like that:
[[asset defaultRepresentation] fullResolutionImage]]
This return CGImageRef which I want to save to disk as fast as possible...
Solution 1:
UIImage*currentImage =[UIImage imageWithCGImage:[[asset defaultRepresentation] fullResolutionImage]];
NSData*currentImageData =UIImagePNGRepresentation(currentImage);
[currentImageData writeToFile:filePath atomically:YES];
Solution 2:
CFURLRef url =(__bridge CFURLRef)[NSURL fileURLWithPath:filePath];
CGImageDestinationRef destination =CGImageDestinationCreateWithURL(url, kUTTypePNG,1, NULL);
CGImageDestinationAddImage(destination,[[asset defaultRepresentation] fullResolutionImage],nil);
CGImageDestinationFinalize(destination);
The problem is that both methods are very slow performing on a device. I takes about 2 seconds per image to perform this. And this is absolutely to long.
Question: How can I speed up this image saving process? Or perhaps is there a better solution for this?
UPDATE: The best performance improvements in both solutions is to save images to JPEG format instead of PNG. So for solution 1 have replaced UIImagePNGRepresentation with UIImageJPEGRepresentation. For solution 2 have replaced kUTTypePNG with kUTTypeJPEG.
Also worth noting that second solution is way more memory efficient that first one.