如何使用 UISlider 快速调整亮度对比度饱和度

Question

过去几天我一直在寻找如何通过手动操作亮度、对比度、高光、阴影、暖度等来实现对UIImage 的过滤器。使用UISlider？

这是我目前用于调整亮度的代码..

let currentValue = Int(editPictureView.sliderView.value)
editPictureView.currentPropertyValue.text = String(currentValue) + " "    
brightnessFilter.setValue(NSNumber(value: editPictureView.sliderView.value), forKey: "inputBrightness")
outputImage = brightnessFilter.outputImage!
//let imageRef = context.createCGImage(outputImage, from: outputImage.extent)
newUIImage = UIImage(ciImage: outputImage)
editPictureView.selectedImageToEdit.image = newUIImage;

但我收到一条错误消息，指出它在展开时发现了 nil。 我所要求的只是让你分享你第一次解决这个问题时的感受，如果你能解释它，你自己也会更好地理解它，或者至少像故事那样。 但老实说，提前谢谢你。

Answer 1

func imageBrightness(imgView : UIImageView , sliderValue : CGFloat, image: UIImage){
        let aCGImage = image.cgImage
        aCIImage = CIImage(cgImage: aCGImage!)
        context = CIContext(options: nil)
        brightnessFilter = CIFilter(name: "CIColorControls")
        brightnessFilter.setValue(aCIImage, forKey: "inputImage")

        brightnessFilter.setValue(sliderValue, forKey: "inputBrightness")
        outputImage = brightnessFilter.outputImage!
        let cgimg = context.createCGImage(outputImage, from: outputImage.extent)
        newUIImage = UIImage(cgImage: cgimg!)
        imgView.image = newUIImage
        print("brightness")
    }

调用此方法并传递滑块值和图像，如下所示： imageBrightnessEdit(imgView: self.imgView, sliderValue: CGFloat(value), image: imgSelected)

对比：

func imageContrast(imgView : UIImageView , sliderValue : CGFloat, image: UIImage){

        let aUIImage = image
        let aCGImage = aUIImage.cgImage

        aCIImage = CIImage(cgImage: aCGImage!)
        context = CIContext(options: nil)
        contrastFilter = CIFilter(name: "CIColorControls")
        contrastFilter.setValue(aCIImage, forKey: "inputImage")

        aCIImage = CIImage(cgImage: aCGImage!)
        context = CIContext(options: nil)
        contrastFilter = CIFilter(name: "CIColorControls")
        contrastFilter.setValue(aCIImage, forKey: "inputImage")
        contrastFilter.setValue(sliderValue, forKey: "inputContrast")
        outputImage = contrastFilter.outputImage!
        let cgimg = context.createCGImage(outputImage, from: outputImage.extent)
        newUIImage = UIImage(cgImage: cgimg!)
        imgView.image = newUIImage
        print("contrast")

    }