ALAsset defaultRepresentation fullResolutionImage

Question

我有新的iOS 7照片滤镜功能的问题.

我的应用程序中有一个photolibrary.当我在UICollectionView中显示照片的缩略图时,我会收到已应用过滤器和裁剪的图像.有两种方法可以返回"随时可用"的图像:

• [asset thumbnail]
• [[asset defaultRepresentation] fullScreenImage]

相反,当我想分享全尺寸图像时,我会收到没有任何过滤器的未更改照片:

• [[asset defaultRepresentation] fullResolutionImage]
• 通过getBytes读取图像数据:fromOffset:length:error:

是否可以使用适当的过滤器获取完整尺寸的图像？

Answer 1

到目前为止,我只找到了一种方法来获得我想要的东西.所有资产都通过密钥在元数据字典中存储其修改(如过滤器,作物等)信息@"AdjustmentXMP".我们能够解释这些数据并fullResolutionImage在此SO答案中应用所有过滤器.这是我的完整解决方案:

...
ALAssetRepresentation *assetRepresentation = [asset defaultRepresentation];
CGImageRef fullResImage = [assetRepresentation fullResolutionImage];
NSString *adjustment = [[assetRepresentation metadata] objectForKey:@"AdjustmentXMP"];
if (adjustment) {
    NSData *xmpData = [adjustment dataUsingEncoding:NSUTF8StringEncoding];
    CIImage *image = [CIImage imageWithCGImage:fullResImage];

    NSError *error = nil;
    NSArray *filterArray = [CIFilter filterArrayFromSerializedXMP:xmpData
                                                 inputImageExtent:image.extent
                                                            error:&error];
    CIContext *context = [CIContext contextWithOptions:nil];
    if (filterArray && !error) {
        for (CIFilter *filter in filterArray) {
            [filter setValue:image forKey:kCIInputImageKey];
            image = [filter outputImage];
        }
        fullResImage = [context createCGImage:image fromRect:[image extent]];
    }   
}
UIImage *result = [UIImage imageWithCGImage:fullResImage
                                      scale:[assetRepresentation scale]
                                orientation:(UIImageOrientation)[assetRepresentation orientation]];