Question

我正试图从屏幕上显示的ImageView获取CIImage。

UIImage *image = myImageView.image;

将图片UIImage转换为CIImage。

CIImage *cImage = [....];

怎么做？

Answer 1

CIImage *ciImage = [UIImage imageNamed:@"test.png"].CIImage;
UIImage *uiImage = [[UIImage alloc] initWithCIImage:ciImage];

要修复myUIImage.CIImage返回nil [UIImageView image]之类的情况，您可以改为[CIImage imageWithCGImage:myUIImage.CGImage] - Dylan Hand

Swift版本：

let ciImage = UIImage(named: "test.png")!.ciImage
let uiImage = UIImage(cgImage: ciImage)

Answer 2

虽然Changxing Wang的回答是有效的，但Apple说UIImage.CIImage并不总是有效。具体来说，来自PocketCoreImage：

// Create a CIImage from the _inputImage.  While UIImage has a property returning
// a CIImage representation of it, there are cases where it will not work.  This is the
// most compatible route.
_filteredImage = [[CIImage alloc] initWithCGImage:_inputImage.CGImage options:nil];

Apple也使用以下内容，但这对我不起作用：

[UIImage imageWithCIImage:_filteredImage]

我的个人实施改编自this post对我有用：

// result is a CIImage, output of my filtering.  
// returnImage is (obviously) a UIImage that I'm going to return.
CIContext *context = [CIContext contextWithOptions:nil];
UIImage *returnImage = 
[UIImage imageWithCGImage:[context createCGImage:result fromRect:result.extent]];

Answer 3

这是最兼容的方式：

UIImage* u =[UIImage imageNamed:@"image.png"];
CIImage* ciimage = [[CIImage alloc] initWithCGImage:u.CGImage];

现在使用ciimage ...

Answer 4

这是我在项目中使用的完整代码示例。

- (UIImage *)makeUIImageFromCIImage:(CIImage *)ciImage {
    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef cgImage = [context createCGImage:ciImage fromRect:[ciImage extent]];

    UIImage* uiImage = [UIImage imageWithCGImage:cgImage];
    CGImageRelease(cgImage);

    return uiImage;
}

CIImage基本上是图像的配方。如果您尝试直接从CIImage转换为UIImage，则会遇到问题。例如，调用

NSData * UIImageJPEGRepresentation (
   UIImage *image,
   CGFloat compressionQuality
);

将返回nil。

Answer 5

func toCIImage(image: UIImage) -> CIImage {
    return image.CIImage ?? CIImage(CGImage: image.CGImage!)
}

func toUIImage(image: CIImage) -> UIImage {
    return UIImage(CIImage: image)
}

Answer 6

changx答案的快速示例：

guard let ciimage = CIImage(image: uiimage) else { return }
let image = UIImage(CIImage: ciimage)

Answer 7

Swift 3/4

UIImage＆gt; CIImage

let ciimage = CIImage(image: image)

https://developer.apple.com/documentation/uikit/uiimage/1624090-init

CIImage＆gt;的UIImage

let image = UIImage(ciImage: ciimage)

https://developer.apple.com/documentation/coreimage/ciimage/1624119-init

Answer 8

当将UIImage转换为CIImage时，我有两个独立的案例，有时甚至是零，有时不是。下面的代码解决了它：

CIImage *ciImage;
ciImage=[[CIImage alloc] initWithImage:imageToConvert];
if (ciImage==nil)
    ciImage=imageToConvert.CIImage;

如何将UIImage转换为CIImage，反之亦然

8 个答案: