如何在 UIView 上制作斜角？

Question

这里有很多关于使UIView 的角变圆的问题。不幸的是，我找不到任何关于如何制作有角度的角的信息。我怎样才能制作一个 UIView 以 45 度角切角？

如果你能告诉我如何让任何人以一定角度切角，你甚至可以获得额外的（象征性的）金星。

编辑：作为参考，here's a link 到一个我怀疑与此解决方案有类似实现的问题。我只是不知道我必须改变什么。

Answer 1

首先你需要一个有角的路径：

- (CGPathRef) makeAnglePathWithRect: (CGRect)rect withSize:(float) s {

    CGPoint one = CGPointMake( rect.origin.x +s, rect.origin.y);
    CGPoint two = CGPointMake( rect.origin.x + rect.size.width - s, rect.origin.y);

    CGPoint three = CGPointMake( rect.origin.x + rect.size.width, rect.origin.y +s);
    CGPoint four = CGPointMake( rect.origin.x + rect.size.width, rect.origin.y + rect.size.height -s);

    CGPoint five = CGPointMake( rect.origin.x + rect.size.width-s, rect.origin.y + rect.size.height);
    CGPoint six = CGPointMake(rect.origin.x+s, rect.origin.y + rect.size.height);

    CGPoint seven = CGPointMake(rect.origin.x, rect.origin.y + rect.size.height-s);
    CGPoint eight = CGPointMake(rect.origin.x, rect.origin.y + s);

    CGMutablePathRef path = CGPathCreateMutable();
    CGPathMoveToPoint(path,NULL,one.x, one.y);
    CGPathAddLineToPoint(path,NULL,two.x, two.y);
    CGPathAddLineToPoint(path,NULL,three.x, three.y);
    CGPathAddLineToPoint(path,NULL,four.x, four.y);
    CGPathAddLineToPoint(path,NULL,five.x, five.y);
    CGPathAddLineToPoint(path,NULL,six.x, six.y);
    CGPathAddLineToPoint(path,NULL,seven.x, seven.y);
    CGPathAddLineToPoint(path,NULL,eight.x, eight.y);
    CGPathAddLineToPoint(path,NULL,one.x, one.y);

    return path;
}

那你需要使用路径来指定掩码：

CAShapeLayer *maskLayer = [CAShapeLayer layer];
CGRect bounds = CGRectMake(0.0f, 0.0f, 100, 100); //figure out your bounds

[maskLayer setFrame:bounds];
CGPathRef p = [self makeAnglePathWithRect:bounds withSize:20.0];
maskLayer.path = p;
_myview.layer.mask = maskLayer;

如果您想从任何角落移除角度，请调整点 1-8，移除“s”值。您可以使用 size 参数更改从角上切出的三角形的大小。

Answer 2

从@nont 中汲取灵感并使用扩展，我编写了这个 sn-p：

extension UIView {

    public enum Corner: Int {
        case TopRight
        case TopLeft
        case BottomRight
        case BottomLeft
        case All
    }

    public func blendCorner(corner corner: Corner, length: CGFloat = 20.0) {
        let maskLayer = CAShapeLayer()
        var path: CGPathRef?
        switch corner {
        case .All:
            path = self.makeAnglePathWithRect(self.bounds, topLeftSize: length, topRightSize: length, bottomLeftSize: length, bottomRightSize: length)
        case .TopRight:
            path = self.makeAnglePathWithRect(self.bounds, topLeftSize: 0.0, topRightSize: length, bottomLeftSize: 0.0, bottomRightSize: 0.0)
        case .TopLeft:
            path = self.makeAnglePathWithRect(self.bounds, topLeftSize: length, topRightSize: 0.0, bottomLeftSize: 0.0, bottomRightSize: 0.0)
        case .BottomRight:
            path = self.makeAnglePathWithRect(self.bounds, topLeftSize: 0.0, topRightSize: 0.0, bottomLeftSize: 0.0, bottomRightSize: length)
        case .BottomLeft:
            path = self.makeAnglePathWithRect(self.bounds, topLeftSize: 0.0, topRightSize: 0.0, bottomLeftSize: length, bottomRightSize: 0.0)
        }
        maskLayer.path = path
        self.layer.mask = maskLayer
    }

    private func makeAnglePathWithRect(rect: CGRect, topLeftSize tl: CGFloat, topRightSize tr: CGFloat, bottomLeftSize bl: CGFloat, bottomRightSize br: CGFloat) -> CGPathRef {
        var points = [CGPoint]()

        points.append(CGPointMake(rect.origin.x + tl, rect.origin.y))
        points.append(CGPointMake(rect.origin.x + rect.size.width - tr, rect.origin.y))
        points.append(CGPointMake(rect.origin.x + rect.size.width, rect.origin.y + tr))
        points.append(CGPointMake(rect.origin.x + rect.size.width, rect.origin.y + rect.size.height - br))
        points.append(CGPointMake(rect.origin.x + rect.size.width - br, rect.origin.y + rect.size.height))
        points.append(CGPointMake(rect.origin.x + bl, rect.origin.y + rect.size.height))
        points.append(CGPointMake(rect.origin.x, rect.origin.y + rect.size.height - bl))
        points.append(CGPointMake(rect.origin.x, rect.origin.y + tl))

        let path = CGPathCreateMutable()
        CGPathMoveToPoint(path, nil, points.first!.x, points.first!.y)
        for point in points {
            if point != points.first {
                CGPathAddLineToPoint(path, nil, point.x, point.y)
            }
        }
        CGPathAddLineToPoint(path, nil, points.first!.x, points.first!.y)
        return path
    }

}

这样你可以轻松地融合你的角落：

let view = UIView()
view.blendCorner(corner: .TopRight)
// or view.blendCorner(corner: .All)

Answer 3

这是一种方法。给定：

const CGFloat kRadius = 20.0; //'radius' of the corner clip

并在您的视图中给出此属性：

@property (nonatomic,strong) CAShapeLayer *maskLayer;

您可以设置一个带有斜角线连接的简单遮罩层（很容易为您提供所需的 45 度角）：

CAShapeLayer *maskLayer = [CAShapeLayer layer];

maskLayer.lineWidth = kRadius * 2.0;
maskLayer.lineJoin = kCALineJoinBevel;
maskLayer.strokeColor = [[UIColor blackColor] CGColor];

self.layer.mask = self.maskLayer = maskLayer;

然后在适当的时候（比如在您的-[ViewClass layoutSublayersOfLayer:] 中）只需将遮罩层的路径设置为半径插入的矩形路径：

self.maskLayer.path = CGPathCreateWithRect(CGRectInset(self.bounds,kRadius,kRadius), NULL);

这是一种无需手动绘制路径的每一部分的方法。您实际上是在使用斜角线连接来为您完成这项工作。