如何使用 UISlider 在 swift 中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使用UISlider手动操作亮度、对比度、高光、阴影、暖度等来为UIImage实现过滤器？

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;

但是我收到一个错误，指出它在解开包装时发现了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，或者至少像故事一样。 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")
}