Ios Swift无法从UIImage中删除CIFIlter

现在已经在swift上工作了一段时间，在处理这个核心图像框架时遇到了困难。我能够成功地在图像上创建CIFilter，但是我不确定如何删除它。将图像放置在与snapchat相机屏幕相似的UIView上，然后有一个imageview，它是预览图像的UIView的子视图。顺便说一句，使用最新版本的Xcode和iOS

以下是应用黑白过滤器时的代码：

@IBAction func BW_Flt_Bt_Tapped(sender: UIButton) {
    let beginImage = CIImage(image: imagePreview.image!)
    let ciContext = CIContext(options: nil)
    let filter = CIFilter(name: "CIPhotoEffectNoir")
    var imgOrientation = imagePreview.image!.imageOrientation
    var imgScale = imagePreview.image?.scale
    filter!.setDefaults()
    filter!.setValue(beginImage, forKey: kCIInputImageKey)
    let filteredImageData = filter!.valueForKey(kCIOutputImageKey) as! CIImage
    let filteredImageRef = ciContext.createCGImage(filteredImageData, fromRect: filteredImageData.extent)
    imagePreview.image = UIImage(CGImage: filteredImageRef, scale: 1.0, orientation: UIImageOrientation.Right)
    self.orgImgBt.hidden = false
    self.orgImgL.hidden = false
    BWFlt.hidden = true
    BWLbl.hidden = true





}

-imagePreview是UIView的子视图

下一步是我的代码如何更改回图像

@IBAction func orgImgPressed(sender: UIButton) {
     self.imagePreview.image = self.selctedImage
    orgImgBt.hidden = true
    orgImgL.hidden = true
   `enter code here` BWFlt.hidden = false
    `enter code here`BWLbl.hidden = false


            print("button was pressed")
        }

---

如果有人有任何建议，我将非常感激，谢谢

您可能应该保留对原始图像的引用，而不仅仅是将过滤器应用于当前在

UIImageView

中显示的任何图像，因为应用过滤器后，您将输出图像设置为

UIImageView

，并且无法检索输入图像。另一个选项是保留对

CIFilter

的引用。为此，您应该声明一个属性：

let noirFilter = CIFilter(name: "CIPhotoEffectNoir")!

然后，您可以在应用过滤器中使用此过滤器，并还原为原始方法

@IBAction func BW_Flt_Bt_Tapped(sender: UIButton) {

    let beginImage = CIImage(image: imagePreview.image!)
    noirFilter.setValue(beginImage, forKey: kCIInputImageKey)
    let filteredImage = noirFilter.valueForKey(kCIOutputImageKey) as! CIImage
    imagePreview.image = UIImage(CIImage: filteredImage)

    self.orgImgBt.hidden = false
    self.orgImgL.hidden = false
    BWFlt.hidden = true
    BWLbl.hidden = true
}

@IBAction func orgImgPressed(sender: UIButton) {

    let inputImage = noirFilter.valueForKey(kCIInputImageKey) as! CIImage
    imagePreview.image = UIImage(CIImage: inputImage)

    orgImgBt.hidden = true
    orgImgL.hidden = true
   `enter code here` BWFlt.hidden = false
   `enter code here`BWLbl.hidden = false


    print("button was pressed")
}

或者更理想地说：

@IBAction func orgImgPressed(sender: UIButton) {

    imagePreview.image = self.currentInputImage

    orgImgBt.hidden = true
    orgImgL.hidden = true
   `enter code here` BWFlt.hidden = false
   `enter code here`BWLbl.hidden = false


    print("button was pressed")
}

---

其中，

currentInputImage

是对要应用筛选器的

UIImage

的引用。

可以通过在变量中保留以前的值或如果有多个筛选器，则将该值保留在字典中来实现。应用新过滤器或更改现有过滤器的值时，只需将该值替换为新值并应用原始图像上的所有值即可

比如说,

    var allFilters = [String: [String: Any]]()
    var currentImage: CIImage!
    let kCIColorControls = "CIColorControls"

    override func viewDidLoad() {
        super.viewDidLoad()
        currentImage = CIImage(image: self.originalImage!)
    }

    func applyAvailableFilters() {
            if self.allFilters.count > 0 {            
                DispatchQueue.global(qos: .background).async {
                    var outputImage: CIImage!

                    self.blurFilter = CIFilter.init(name: "CIGaussianBlur")
                    self.brightnessFilter = CIFilter.init(name: "CIColorControls")
                    self.cropFilter = CIFilter.init(name: "CICrop")

                    if let blurProperty = self.allFilters[self.kCIGaussianBlur]?.first {
                        self.blurFilter.setValue(blurProperty.value, forKey: blurProperty.key)
                                                self.blurFilter.setValue(self.currentImage, forKey: kCIInputImageKey)
                        outputImage = self.blurFilter.outputImage
                    }

                    if let brightnessProperty = self.allFilters[self.kCIColorControls]?.first {
                        self.brightnessFilter.setValue(brightnessProperty.value, forKey: brightnessProperty.key)
                        if let outputImage = self.blurFilter.outputImage {
                            self.brightnessFilter.setValue(outputImage, forKey: kCIInputImageKey)
                        } else {
                            self.brightnessFilter.setValue(self.currentImage, forKey: kCIInputImageKey)
                        }
                        outputImage = self.brightnessFilter.outputImage
                    }

                    if let cropProperty = self.allFilters[self.kCICrop]?.first {
                        self.cropFilter.setValue(cropProperty.value, forKey: cropProperty.key)
                        if let outputImage = self.brightnessFilter.outputImage {
                            self.cropFilter.setValue(outputImage, forKey: kCIInputImageKey)
                        } else if let outputImage = self.blurFilter.outputImage {
                            self.cropFilter.setValue(outputImage, forKey: kCIInputImageKey)
                        } else {
                            self.cropFilter.setValue(self.currentImage, forKey: kCIInputImageKey)
                        }
                        outputImage = self.cropFilter.outputImage
                    }

                    if let image = outputImage {
                        let openGLContext = EAGLContext(api: .openGLES2)
                        let context = CIContext(eaglContext: openGLContext!)
                        if let cgimg = context.createCGImage(image, from: image.extent) {
                            let processedImage = UIImage(cgImage: cgimg)
                            DispatchQueue.main.async {
                                self.imageView.image = processedImage
                            }
                        }
                    } else {
                        DispatchQueue.main.async {
                            self.imageView.image = self.selectedImage
                        }
                    }
                }
            } else {
                DispatchQueue.main.async {
                    self.imageView.image = self.selectedImage
                }
            }
        }

然后像这样应用过滤器（模糊过滤器）

---

什么是

self.selectedImage

？这确实给了我想要的图像，但是它旋转且比原始图像小，有没有关于如何纠正的建议？您是否尝试使用

UIImage（CIImage:，scale:，orientation:）

而不是

UIImage（CIImage:）

？

@IBAction func sliderValueChanged(_ sender: UISlider) {
      if sender.value == 0 {
            _ = allFilters.removeValue(forKey: kCIGaussianBlur)
        } else {
            allFilters[kCIGaussianBlur] = [kCIInputRadiusKey: sender.value]
        }
        if allFilters[kCICrop]?.first == nil {
            allFilters[kCICrop] = ["inputRectangle": CIVector(cgRect: self.currentImage.extent)]
        }
        applyAvailableFilters()
}