App crash when get fullResolutionImage - iphone

Question

I try using my app ALAssetRepresentation.and when i loop om an images there are couple of image that crash the app
for(ALAsset *asset in _assets) {
NSMutableDictionary *workingDictionary = [[NSMutableDictionary alloc] init];
[workingDictionary setObject:[asset valueForProperty:ALAssetPropertyType] forKey:#"UIImagePickerControllerMediaType"];
ALAssetRepresentation *representation = [asset defaultRepresentation];
if (!representation) {
[workingDictionary release];
continue;
}
CGImageRef imageRef = [representation fullResolutionImage];//here the app crash
UIImage *img = [UIImage imageWithCGImage:imageRef];
if (!img) {
[workingDictionary release];
continue;
}
if (!img) {
[workingDictionary release];
continue;
}
[workingDictionary setObject:img forKey:#"UIImagePickerControllerOriginalImage"];
[workingDictionary setObject:[asset valueForProperty:ALAssetPropertyOrientation] forKey:#"orientation"];
[returnArray addObject:workingDictionary];
[workingDictionary release];
}
in this line i get crash without any msg:
CGImageRef imageRef = [representation fullResolutionImage];
This is the crash msg
Program received signal: “0”.
Data Formatters temporarily unavailable, will re-try after a 'continue'. (Unknown error loading shared library "/Developer/usr/lib/libXcodeDebuggerSupport.dylib")

Answer 1

That is most likely due to running out of memory, how big are the images that cause the crash?

Answer 2

I had a similar problem and after hours of lookin for solution I found this - the best solution of too big Asset bug:
// For details, see http://mindsea.com/2012/12/18/downscaling-huge-alassets-without-fear-of-sigkill
#import <AssetsLibrary/AssetsLibrary.h>
#import <ImageIO/ImageIO.h>
// Helper methods for thumbnailForAsset:maxPixelSize:
static size_t getAssetBytesCallback(void *info, void *buffer, off_t position, size_t count) {
ALAssetRepresentation *rep = (__bridge id)info;
NSError *error = nil;
size_t countRead = [rep getBytes:(uint8_t *)buffer fromOffset:position length:count error:&error];
if (countRead == 0 && error) {
// We have no way of passing this info back to the caller, so we log it, at least.
NSLog(#"thumbnailForAsset:maxPixelSize: got an error reading an asset: %#", error);
}
return countRead;
}
static void releaseAssetCallback(void *info) {
// The info here is an ALAssetRepresentation which we CFRetain in thumbnailForAsset:maxPixelSize:.
// This release balances that retain.
CFRelease(info);
}
// Returns a UIImage for the given asset, with size length at most the passed size.
// The resulting UIImage will be already rotated to UIImageOrientationUp, so its CGImageRef
// can be used directly without additional rotation handling.
// This is done synchronously, so you should call this method on a background queue/thread.
- (UIImage *)thumbnailForAsset:(ALAsset *)asset maxPixelSize:(NSUInteger)size {
NSParameterAssert(asset != nil);
NSParameterAssert(size > 0);
ALAssetRepresentation *rep = [asset defaultRepresentation];
CGDataProviderDirectCallbacks callbacks = {
.version = 0,
.getBytePointer = NULL,
.releaseBytePointer = NULL,
.getBytesAtPosition = getAssetBytesCallback,
.releaseInfo = releaseAssetCallback,
};
CGDataProviderRef provider = CGDataProviderCreateDirect((void *)CFBridgingRetain(rep), [rep size], &callbacks);
CGImageSourceRef source = CGImageSourceCreateWithDataProvider(provider, NULL);
CGImageRef imageRef = CGImageSourceCreateThumbnailAtIndex(source, 0, (__bridge CFDictionaryRef) #{
(NSString *)kCGImageSourceCreateThumbnailFromImageAlways : #YES,
(NSString *)kCGImageSourceThumbnailMaxPixelSize : [NSNumber numberWithInt:size],
(NSString *)kCGImageSourceCreateThumbnailWithTransform : #YES,
});
CFRelease(source);
CFRelease(provider);
if (!imageRef) {
return nil;
}
UIImage *toReturn = [UIImage imageWithCGImage:imageRef];
CFRelease(imageRef);
return toReturn;
}