Question

首先，我问办公室的老人甚至老板，但他们没有回复我的问题。 - 如何在同一时间使用两个过滤器保存一张照片？

我有一个使用PHAssets编辑资源元数据（照片/视频）的项目。现在，我可以通过应用标签和过滤器来修改图像。请参阅此示例：http://dev.classmethod.jp/references/ios8-photo-kit-4/

我最近有一个关于CIGaussianBlur生成的额外边框的问题，我了解到我必须使用CIAffineClamp过滤器来解决问题：CIGaussianBlur and CIAffineClamp on iOS 6

不幸的是，当我需要应用两个过滤器时，我不知道如何保存PHAsset或修改PHAsset。这是我应用这两个过滤器的代码：

    // G: If Blur, then adjust first the frame before applying blur!
    if ([filterName isEqualToString:@"CIGaussianBlur"])
    {
        [filter setValue:inputImageForFilter forKey:@"inputImage"];
        CGFloat blurLevel = 20.0f;
        [filter setValue:[NSNumber numberWithFloat:blurLevel] forKey:@"inputRadius"];

        CIImage* filterInputImage = [CIImage imageWithCGImage:originalImage.CGImage];
        CIFilter* filter = [CIFilter filterWithName:filterName];

        CIFilter *clampFilter = [CIFilter filterWithName:@"CIAffineClamp"];
        [clampFilter setDefaults];
        [clampFilter setValue:filterInputImage forKey:kCIInputImageKey];

        [filter setValue:clampFilter.outputImage forKey:kCIInputImageKey];
        [filter setValue:@10.0f forKey:@"inputRadius"];

        CIImage* filterOutputImage = [filter valueForKey:kCIOutputImageKey];

        CGImageRef createdImage = [context createCGImage:filterOutputImage fromRect:[filterInputImage extent]];
        UIImage* outputImage = [UIImage imageWithCGImage:createdImage];

        dispatch_async(dispatch_get_main_queue(), ^{
            strongSelf.capturedImageView.image = outputImage;
            strongSelf.capturedImageView.contentMode = UIViewContentModeScaleAspectFit;
            [strongSelf.capturedImageView layoutSubviews];
        });

        strongSelf.appliedFilter.filterName = filterName;
        strongSelf.appliedFilter.editingInput = contentEditingInput;
        strongSelf.appliedFilter.outputImage = filterOutputImage;

        CGImageRelease(createdImage);
        createdImage = nil;
    }

这是保存数据的代码：

- (void)doneButtonAction:(id)sender
{
    // G: Handle Nil FilterName for Fixing Crash :)
    if (self.appliedFilter.filterName == nil) {
        // G: just pop to the view controller next to root, which is the Camera View Controller in Photo Mode.
        [self.navigationController popToViewController:self.navigationController.viewControllers[1] animated:YES];
    }

    else{
        // Create a PHAdjustmentData object that describes the filter that was applied.
        PHAdjustmentData *adjustmentData = [[PHAdjustmentData alloc] initWithFormatIdentifier:AdjustmentFormatIdentifier formatVersion:@"1.0" data:[self.appliedFilter.filterName dataUsingEncoding:NSUTF8StringEncoding]];

        PHAdjustmentData *affineClamp = [[PHAdjustmentData alloc] initWithFormatIdentifier:AdjustmentFormatIdentifier formatVersion:@"1.0" data:[@"CIAffineClamp" dataUsingEncoding:NSUTF8StringEncoding]];

        /*
         Create a PHContentEditingOutput object and write a JPEG representation
         of the filtered object to the renderedContentURL.
         */
        PHContentEditingOutput *contentEditingOutput = [[PHContentEditingOutput alloc] initWithContentEditingInput:self.appliedFilter.editingInput];
        NSData *jpegData = [self.appliedFilter.outputImage aapl_jpegRepresentationWithCompressionQuality:0.9f];
        [jpegData writeToURL:[contentEditingOutput renderedContentURL] atomically:YES];
        [contentEditingOutput setAdjustmentData:adjustmentData];

        if ([self.appliedFilter.filterName isEqualToString:@"CIGaussianBlur"]) {
            [contentEditingOutput setAdjustmentData:affineClamp];
        }

        // Ask the shared PHPhotoLinrary to perform the changes.
        [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
            PHAssetChangeRequest *request = [PHAssetChangeRequest changeRequestForAsset:self.photo.asset];
            request.contentEditingOutput = contentEditingOutput;
        } completionHandler:^(BOOL success, NSError *error) {
            if (!success) {
                NSLog(@"Error: %@", error);
            }
        }];

        // G: just pop to the view controller next to root, which is the Camera View Controller in Photo Mode.
        [self.navigationController popToViewController:self.navigationController.viewControllers[1] animated:YES];

    }

}

同样，如果我只有1个过滤器可以应用，那么保存数据部分代码的效果非常好。所以，我的问题是如何在有两个要应用的过滤器时调整数据。非常感谢。我相信我的问题很清楚。 ;）期待你的回答。

Answer 1

首先，我不知道如何重新声明*过滤而不会出现错误（必须首先在控制结构之外声明，然后在其中重新声明）。

这是一个简单的例程，它将应用您的模糊并返回包含您正在寻找的范围的图像。

- (CIImage*)blurImage:(CIImage*)sourceImage withRadius:(NSNumber*)blurRadius {

    CGRect originalExtent = sourceImage.extent;

    CIImage *clampedImaged = [sourceImage imageByClampingToExtent];

    CIImage *blurredImage = [clampedImaged imageByApplyingFilter:@"CIGaussianBlur" withInputParameters:@{@"inputRadius" : blurRadius}];

    return [blurredImage imageByCroppingToRect:originalExtent];
}

否则，我无法告诉你originalImage或inputImageForFilter指的是什么，所以很难说出挂断的位置。你可以逐行调试这个并使用Xcode的peek函数（eyeball图标）来确保从每个过滤器生成的CIImage对象是你期望的。

使用CIGaussianBlur和CIAffineClamp保存PHAsset

1 个答案: