我希望使用ALAssetsLibrary和ALAsset直接以NSData对象的形式提取图像。
使用NSURL,我以以下方式取出图像。
NSURL *referenceURL =newURL;
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library assetForURL:referenceURL resultBlock:^(ALAsset *asset)
{
UIImage *copyOfOriginalImage = [UIImage imageWithCGImage:[[asset defaultRepresentation] fullResolutionImage]];
}
现在,我们将图像作为UIImage,但我需要直接将图像作为NSData。
我希望这样做是因为(我已经读过了)一旦你在UIImage中拍摄图像,那么我们就会丢失图像的所有EXIF细节。
这就是为什么我要将图像直接提取为NSData,而不是这样做的原因
NSData *webUploadData=UIImageJPEGRepresentation(copyOfOriginalImage, 0.5);
这一步会使我丢失所有的EXIF细节。
请帮帮忙。
发布于 2011-12-12 19:55:43
ALAssetsLibrary *assetLibrary=[[ALAssetsLibrary alloc] init];
[assetLibrary assetForURL:[[self.imagedata objectAtIndex:i] resultBlock:^(ALAsset *asset)
{
ALAssetRepresentation *rep = [asset defaultRepresentation];
Byte *buffer = (Byte*)malloc(rep.size);
NSUInteger buffered = [rep getBytes:buffer fromOffset:0.0 length:rep.size error:nil];
NSData *data = [NSData dataWithBytesNoCopy:buffer length:buffered freeWhenDone:YES];//this is NSData may be what you want
[data writeToFile:photoFile atomically:YES];//you can save image later
}
failureBlock:^(NSError *err) {
NSLog(@"Error: %@",[err localizedDescription]);
}];
发布于 2014-07-10 10:46:19
使用以下代码:
+ (BOOL)exportDataToURL:(NSString *)filePath error:(NSError **)error andAsset:(ALAsset *)asset
{
[[NSFileManager defaultManager] createFileAtPath:filePath contents:nil attributes:nil];
NSFileHandle *handle = [NSFileHandle fileHandleForWritingAtPath:filePath];
if (!handle)
return NO;
static const NSUInteger BufferSize = 1024 * 1024;
ALAssetRepresentation *rep = [asset defaultRepresentation];
uint8_t *buffer = calloc(BufferSize, sizeof(*buffer));
NSUInteger offset = 0, bytesRead = 0;
do {
@try {
bytesRead = [rep getBytes:buffer fromOffset:offset length:BufferSize error:error];
[handle writeData:[NSData dataWithBytesNoCopy:buffer length:bytesRead freeWhenDone:NO]];
offset += bytesRead;
} @catch(NSException *exception) {
free(buffer);
return NO;
}
} while (bytesRead > 0);
free(buffer);
return YES;
}
发布于 2012-11-02 15:12:00
UIImage * selImage = [UIImage imageWithCGImage:[asset thumbnail]];
NSData *baseImage=UIImagePNGRepresentation(selImage);
https://stackoverflow.com/questions/8473110
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