Question

现在正在研究swift，并且无法解决这个Core Image Framework问题。我能够在图像上成功创建CIFilter但是我不确定如何删除它。图像被放置在类似于Snapchat的相机屏幕的UIView上，然后有一个图像视图，它是预览图像的uiview的子视图。 BTW使用最新版本的Xcode和iOS。

以下是应用黑白滤镜时的代码：

@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

接下来是关于如何更改图像的代码

@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会非常感激，谢谢！

Answer 1

您可以通过将先前值保留在变量中，或者如果您有多个过滤器将这些值保留在字典中。当您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CIImage上的所有值

例如，

    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
                }
            }
        }

然后像这样应用滤镜（模糊滤镜）

@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()
}

Answer 2

您可能应该持有对原始图像的引用，而不仅仅是将过滤器应用于UIImageView中当前显示的任何图像，当您应用过滤器然后将输出图像设置为{{1并且无法检索输入图像。另一种选择是保留对UIImageView的引用。为此，您应该声明一个属性：

CIFilter

然后，您可以在应用过滤器中使用此过滤器并恢复为原始方法。

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

或者更理想的是：

@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")
}

其中@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") }是对您要应用过滤器的currentInputImage的引用。

Swift无法从UIImage中删除CIFIlter

2 个答案: