我创建了一个 CGPath 区域，如绿色圆圈所示。 CGPath区域需要清晰，图像的其余部分将应用模糊或半透明效果，我可以使用以下代码在CGPath内剪切图像：
UIGraphicsBeginImageContext(view.frame.size);
CGContextAddPath(ctx, path);
CGContextClip(ctx);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *clipImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(clipImage, nil, nil, nil);
CGPathRelease(path);
但我不知道如何同时使用 CGPath 应用模糊或半透明效果。我想我可以模糊原始图像并将其与剪辑图像合并，但我不知道如何实现它。
您需要 2 个概念才能实现最终结果：-
i) CG混合模式 https://developer.apple.com/reference/coregraphics/cgblendmode
ii) CIFilter https://developer.apple.com/reference/coreimage/cifilter
CGBlendMode 用于从图像中删除所需的部分。对当前上下文中彼此存在的路径进行合成操作。
清晰模式的原始值为 16帮助清除所需的部分。
CIFilter 有助于模糊最终图像。
class ConvertToBlurryImage:UIView {
var originalImage:UIImage!
var finalImage:UIImage!
override func draw(_ rect: CGRect) {
super.draw(rect)
//Original Image
originalImage = UIImage(named: "originalImage.png")
//Intermediate Image
let intermediateImage = UIImage().returnBlurImage(image: originalImage)
//Final Result Image
finalImage = blendImage(image: intermediateImage)
let attachedImage = UIImageView(image: finalImage)
addSubview(attachedImage)
}
func blurryImage(image:UIImage) -> UIImage {
UIGraphicsBeginImageContext(frame.size)
image.draw(in: CGRect(origin: frame.origin, size: frame.size) )
// 16 === clear
let mode = CGBlendMode(rawValue: 16)
UIGraphicsGetCurrentContext()!.setBlendMode(mode!)
//Path that need to crop
pathToCrop()
let mode2 = CGBlendMode(rawValue: 16)
UIGraphicsGetCurrentContext()!.setBlendMode(mode2!)
let finalImage = UIGraphicsGetImageFromCurrentImageContext()
return finalImage!
}
func pathToCrop() {
let path = UIBezierPath(ovalIn: CGRect(x: frame.width/2 - 50, y: frame.height/2 - 100 , width: 150, height: 150) )
path.fill()
path.stroke()
}
}
extension UIImage {
func returnBlurImage(image:UIImage) -> UIImage {
let beginImage = CIImage(cgImage: image.cgImage!)
let blurfilter = CIFilter(name: "CIGaussianBlur")
blurfilter?.setValue(beginImage, forKey: "inputImage")
let resultImage = blurfilter?.value(forKey: "outputImage") as! CIImage
let blurredImage = UIImage(ciImage: resultImage)
return blurredImage
}
}
使命达成
最终的 Github 演示 https://github.com/shrawan2015/Application-Demo-StackOverFlow/tree/master/BluryImage
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