Swift

Question

我有一个 UIBezierPath() 使用的蒙版图像，我想在蒙版部分而不是原始图像周围添加边框。在我的（无数次）尝试中，我已经通过反复试验和不知疲倦地放弃了。有更简单的方法吗？

这是我实现目标的程度：

我希望边界向内！ :-(

Swift2码:

let picture = UIImageView(image: UIImage(named: "myPicture.png"))
picture.layer.contentMode = .ScaleAspectFit
picture.layer.clipsToBounds = true

let maskLayer = CAShapeLayer()
picture.layer.mask = maskLayer

maskLayer.frame = CGRect(origin: CGPointZero, size: picture.image.size)
let radius = picture.size.width/2
let center = CGPoint(x: picture.size.width/2, y: picture.size.height/2)

let path = UIBezierPath()
            path.moveToPoint(center)
            path.addArcWithCenter(center, radius: radius, startAngle: 0, endAngle: CGFloat(M_PI*2.0*0.2), clockwise: true)

maskLayer.path = path.CGPath

picture.layer.mask = maskLayer

picture.layer.borderWidth = 3
picture.layer.borderColor = UIColor.purpleColor().CGColor
picture.layer.cornerRadius = picture.layer.bounds.width/2

Answer 1

假设我理解您所说的 "I'd love to have the border go inward" 的意思 - 我建议使用另一个 CAShapeLayer 将您的边框显示为描边路径，并将其作为子图层添加到图像视图的图层中。

您只需要在您为面具定义的路径中设置您的通行证，设置您的 strokeColor 和 lineWidth，并将 fillColor 设置为 clearColor。

像这样应该可以解决问题：

// insert your image here
guard let img = UIImage(named: "4.png") else {
    return
}

// frame of your image view
let frame = CGRectInset(view.bounds, 10, 10)

// your picture view
let pictureView = UIImageView(image: img)
pictureView.frame = frame
pictureView.contentMode = .ScaleAspectFit
pictureView.clipsToBounds = true

// the radius and center of your path
let radius = pictureView.frame.size.width*0.5
let center = CGPoint(x: pictureView.frame.size.width*0.5, y: pictureView.frame.size.height*0.5)

// your masking & stroking path
let path = UIBezierPath()
path.moveToPoint(center)
path.addArcWithCenter(center, radius: radius, startAngle: 0, endAngle: CGFloat(M_PI*2.0*0.8), clockwise: true)
path.closePath()

// the layer used to mask the image view
let maskLayer = CAShapeLayer()
maskLayer.frame = pictureView.bounds
maskLayer.path = path.CGPath
pictureView.layer.mask = maskLayer

// the layer used to draw the border
let strokeLayer = CAShapeLayer()
strokeLayer.frame = pictureView.bounds
strokeLayer.fillColor = UIColor.clearColor().CGColor
strokeLayer.path = path.CGPath
strokeLayer.strokeColor = UIColor.purpleColor().CGColor
strokeLayer.lineWidth = 10
pictureView.layer.addSublayer(strokeLayer)

view.addSubview(pictureView)

给出以下输出：

此外，我会注意到您在 OP 中提供的代码甚至没有编译 - 请始终从 IDE 复制并粘贴您的代码，而不是尝试自己输入！

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